The photocurrent measurements indicated that thepresence of graphene considerably contributed to the visible lightutilization and photocatalytic efficiency of g-C3N4. This contribution was also revealed by the UV–visdiffuse reflectance spectra measurements, which showed that the incrementaladdition of the graphene reduced the optical band gap of the nanocompositeincrementally. The photocatalyst performance of the g-C3N4/graphene nanocomposite was also observed in the photo-assistedcharging tests of the Li-ion oxygen battery, and the presence of 2Dgraphene in the structure improved the effectiveness of g-C3N4 in the reduction of the charging potential, especiallyat high current densities.In this work, weaimed to synthesize an effective nanocompositephotocatalyst for the photo-assisted charging of the Li-ion oxygenbattery. Initially the graphene films were synthesized by chemicalvapor deposition, and subsequently, g-C Dye-sensitized TiO2,1 g-C3N4,2 TiN/TiO2/carbon cloth,3 Au/TiO2 nanotubes,4 TiO2/Fe2O3,5 WO3/g-C3N4,6 and rGO/g-C3N47 were synthesized as photocatalysts for the photo-assisted chargingof the Li-ion oxygen batteries. In addition to the thermodynamic requirements,the visible light harvesting efficiency of the photocatalyst is ananother criterion in the reduction of the charge potential at highcharging current densities.7The photo-assisted chargingof the Li-ion oxygen batteries withthe aid of triiodide/iodide (I9 Graphitic carbon nitride(g-C3N4), a 2D nonmetallic semiconductor, isa very promising photocatalyst owing to its convenient light harvestingband gap (2.7 eV), good physicochemical stability, and easy and low-costsynthesis.14 However, the severe recombination of the photogenerated electron–holepairs, low surface area, and low electrical conductivity restrictits application.15 The synthesis of g-C3N4-based nanocomposites with the carbonaceous nanomaterialsis accepted as the most effective pathway to overcome these handicapssince they are the most compatible constituents of the nanocompositesdue to their similar carbon network and sp2-conjugatedπ structure.24Two-dimensional(2D) materials and their composites are expectedto make a significant impact on the advancement of the energy conversionand storage technologies.2-hybridizedcarbon atoms, attracts worldwide research interest due to its exceptionalphysical properties.25 Graphene finds largepractical applications in microelectronics, optoelectronics, and energystorage.26 Chemical vapor deposition (CVD)is recognized as the most suitable synthesis route to get high quality graphene.27Graphene, a 2D single-layer sheet of sp3H6N6) and g-C3N4/graphene nanocomposites were obtained by thermalreduction at different graphene/g-C3N4 ratios.After structural and optical characterizations of the nanocomposites,the best nanocomposite composition was determined and it was usedas a photocatalyst in the photo-assisted charging of the Li-ion oxygenbattery. The improved photocatalytic activity was obtained in theg-C3N4/graphene nanocomposites since the highquality graphene brought about an increase in both the surface areaand electrical conductivity of g-C3N4. Additionally,the presence of graphene caused a redshift and narrowing of the bandgap slightly in the semiconductor nanocomposites.In this work, following the efforts on the development ofthe effectivephotocatalyst for the Li-ion oxygen battery, a novel nanocompositewas synthesized. Initially, the few layer graphene films were synthesizedon the copper substrate by CVD. Then, the graphene films were mixedwith melamine  cathodes (oxygen electrodes) were reportedin our previous work.Figure S1 on the Cu foil substrate . After the synthesis process,the Cu substrate was dissolved in 50% HCl solution including 0.5 MFeCl3 and the graphene films were collected in high purityethanol. Since the graphene films were covering the Cu foil substratesurface continuously without any damage, the surface area of the graphenefilm was assumed to be equal to the surface area of the Cu foil substrate.For the characterizations of the graphene films, the Cu foil was coatedwith the poly methyl methacrylate (PMMA) on the spin coater and thenthe copper substrate was dissolved. PMMA was also cleaned with acetone/isopropanolcombinations after the coated graphene film was transferred to eitherSiO2/Si or transmission electron microscopy (TEM) grit.Graphene wassynthesized by CVD according to the procedure provided in –1) and heatedup to 550 °C at a rate of 3 °C min–1 andthen kept at this temperature for 3 h. Subsequently, g-C3N4/graphene nanocomposites were collected after coolingto R.T. Nanocomposite compositions were determined according to theratio of graphene surface area to g-C3N4 weight(cm2 graphene/mg g-C3N4).In order to prepare nanocomposites, melamine and graphene weremixed in ethanol at 50 °C until all the ethanol evaporates. Aftercomplete drying, melamine and graphene were put into a crucible (30mL) under continuous Ar flow (1.2 L min2.2–2)by a spin coater and then drying at 100 °C for 12 h in a vacuum-desiccator.The photoelectrochemical measurements were made in a conventionalthree-electrode cell with a platinum wire as the auxiliary electrodeand an Ag/AgCl (saturated KCl) as the reference electrode on a GamryReference 3000 workstation in a spectral cell containing 0.1 M KClbuffered by 0.1 M K2HPO4 to pH 7. The photocurrentswere measured by the linear sweep voltammetry technique, and the semiconductorloading was 0.05 mg cm–2. A solar simulator  was used as the light source. The semiconductor loadingwas 0.8 mg cm–2 for the Mott–Schottky measurements.The working electrode was prepared by loadingthe nanocomposite on ITO glass was used as a separator. The oxygen electrode was prepared by mixingthe porous Pd@rGO/Super P carbon black/PVDF (80:10:10 wt %) in NMP,and then, the slurry was coated onto one side of 16 mm diameter GDL(TGP-H-060) with a loading rate of 0.1 mg cm–2.The semiconductor nanocomposite was coated on the other side of GDLwith a loading rate of 0.05 mg cm–2 as a photoelectrode.Before the battery assembly, the electrodes were dried in a vacuumoven at 100 °C overnight. 0.5 M LiClO4 and 0.05 MLiI dissolved in TEGDME were used as an electrolyte for photo-assistedcharging. LiI was excluded if charging was conducted without illumination.The discharge and charge tests were performed galvanostatically andthe discharge cutoff potential was 2.0 VLi+/Li. The chargecutoff potentials were 3.6 VLi+/Li and 4.2 VLi+/Li for the photoassisted and dark charging, respectively. The currentdensities changed between 10 mA g–1 (10–3 mA cm–2) and 500 mA g–1 (5 ×10–2 mA cm–2).Photo-assisted charging of the Li-ion oxygen battery was carriedout by a homemade cell in an oxygen cabin, which had 1 bar positiveoxygen pressure during the measurements, as shown in our previouswork.2.3–1. The morphologies were examined with a ZEISSUltraplus scanning electron microscope. FTIR measurements were conductedby a PerkinElmer Spectrum Two. The graphene film morphology was characterizedusing a JEOL JEM 2010F transmission electron microscope running at200 kV and atomic force microscopy . UV/vis spectrawere recorded by Cary 5000 UV/vis/NIR spectrometer with a diffusereflectance accessory between 200 and 800 nm. The Raman analysis wascarried out by Raman spectroscopy (RENISHAW RAMAN inVia microscope)with an excitation wavelength of 532 nm.X-raydiffraction (XRD) analyses were performed on a PANalytical Empyreandiffractometer with Cu Kα radiation at a scanning rate of 2°min33.1Figure S2a. Two main peaks can be assigned inthe Raman spectrum. The G (∼1582 cm–1) and2D (∼2694 cm–1) bands are attributed to thesp2 hybridizations of the C atoms.28 The 2D band is sensitive to the number of layers of graphene films.28 The 2D/G intensity ratio is 3.2 in Figure S2a, in which the synthesized graphenelooks to have only a few layers. The absence of the D band in Figure S2a indicates that the graphene filmsare synthesized without any defect. The scanning electron microscopy(SEM) and TEM images of the synthesized graphene on the TEM grit arepresented in Figure S2b,c, respectively.These images reflect the typical few-layer graphene morphology. Itis also understood from the images that there are occasional wrinklesand overlaps. Similar characteristics of the graphene film can alsobe observed in the AFM image in Figure S2d.The normalizedRaman spectra from the synthesized graphene film are provided in 3N4/graphenenanocomposites are determined according to the total surface areaof graphene (cm2) per weight of g-C3N4 (mg) present in the nanocomposite structure. The nanocompositeswith three different compositions are synthesized: 1 cm2 graphene/mg g-C3N4, 2 cm2 graphene/mgg-C3N4, and 3 cm2 graphene/mg g-C3N4. The structural changes in the synthesized nanocompositesare identified by FTIR spectra , as shown in 3N4 andnanocomposites (novel ones) are shown by blue and red dashed lines,respectively, in –1 are associated with N=H stretching  in pure g-C3N4.29 Spectrum peaks located between 1200 and 1650cm–1 are due to the stretching modes of CN heterocycles.29 Peaks located in the range change from 735 to806 cm–1 and at 885 cm–1 are attributedto the triazine ring stretching and N–H band deformation modes,respectively.29 The synthesized nanocompositeshave all of the characteristic peaks of pure g-C3N4. Novel peaks (marked by red dashed lines) in nanocompositeslocated in the range between 2880 and 2950 cm–1 (mediumstrength) and at 660 cm–1 (strong) can be attributedto the C–H stretching vibrations probably due to the interactionof graphene with the residual amino groups or absorbed water, andthe C=C bond bending vibrations, respectively, in 3N4 and graphene duringthe decomposition of melamine to g-C3N4 at 550°C as reported previously.7The composition of the g-C3N4 and g-C3N4/graphene nanocomposites. A strong characteristic(002) peak at 27.6° in the pure g-C3N4 patternis associated with the layered structure.17 The peak at around 13.2° (100) in the pure g-C3N4 pattern in s-triazine units.28 All the nanocompositeshave almost the same characteristic peaks as those of pure g-C3N4 in 2 graphene/mgg-C3N4, 2 cm2 graphene/mg g-C3N4, and 3 cm2 graphene/mg g-C3N4 nanocomposites are provided in Figure S3. Morphologies of the nanocomposites are very similarto that of pure g-C3N4, which has a characteristicslate-like stacked lamellar microstructure.7 No clear change is observed in the nanocomposite morphologies sincethe amount of CVD graphene is considerably small in the nanocompositestructure.The morphologies of thesynthesized 1 cm3.23N4 by the linear sweep voltammetry techniques,as shown in 3N4.The photoanodiccurrents, via on–off cycles under visible-light irradiation,are obtained for all the synthesized nanocomposites and pure g-C3N4 and nanocomposites are given in 3N4 is 485 nm and it increases slightly to 490, 500, and510 nm for 1 cm2 graphene/mg g-C3N4, 2 cm2 graphene/mg g-C3N4, and3 cm2 graphene/mg g-C3N4, respectively.The optical band gaps (Eg) can be obtainedby the Tauc plot,30 as in 3N4, 1 cm2 graphene/mgg-C3N4, 2 cm2 graphene/mg g-C3N4, and 3 cm2 graphene/mg g-C3N4, respectively. It was reported previously that theincorporation of the nanocarbons to g-C3N4 causesa redshift in the absorption band edges of g-C3N4 and thus the absorption band edges shift to the higher wavelengthsand then the corresponding optical band gaps are narrow.7 The redshift in the nanocomposites is attributedto the formation of a novel chemical bonding during the synthesisof the nanocomposites.73N4 nanocomposites.The UV–vis diffuse reflectance spectra of pure g-C3–/I– shuttle for the photo-assistedcharging. If the flat band potential is assumed to be approximatelyequal to the CB edge potential, Mott–Schottky plots can providethe CB edge potential of the photocatalysts as in The VB edge potential of the photocatalysts directly determinesthe photo-oxidation power which is critical to drive I3.3– ions are oxidized to I3– ions by the photoexcited holes of the photocatalystas in –/I3– couple  and spontaneouslyoxidize low-conducting Li2O2 to Li+ ions and O2  and the overall result is thatthe charge potential of the Li-ion oxygen battery is compensated bythe generated photovoltage.1 Thermodynamically,the reduction extension in the charging potential of the Li-ion oxygenbattery is directly related to the level of CB edge potential thatthe lower the CB edge potential, the lower the charging potential.2 Despite the thermodynamic conveniences of allthe tabulated semiconductors in 2 graphene/mg g-C3N4 nanocomposite has the highest photoanodic currents in 3N4 structureimproves the light-harvesting capability of the g-C3N4.If the photoexcited electrons of thephotocatalyst are efficientlyseparated from the photoexcited holes, then they flow to the anodeto reduce the Li3N4 and 3 cm2 graphene/mgg-C3N4 nanocomposite photoelectrodes are preparedand 1 h-long charge curves at various current densities are obtainedas in Li+/Li at 10 mAg–1 (0.001 mA cm–2) in Li+/Li) at 50mA g–1 (0.005 mA cm–2) in –1 (0.01 mA cm–2) in 3N4 photoelectrode passes above the discharge curvewhile that in the presence of 3 cm2 graphene/mg g-C3N4 photoelectrode still in the scale range of thedischarge curve. Further increases in the current densities to 200mA g–1 (0.02 mA cm–2) and 500mA g–1 (0.05 mA cm–2), in 3N4  for 50 cycles under the photoassistanceas in –/I3– couple (3.586 VLi+/Li) acts as a cutoff potential, which is slightly less than the theoreticalpotential in the used electrolyte, for the charging, and when thecharge curve reaches this potential, the charging stops. In the presenceof pure g-C3N4 as a photocatalyst, the chargecurve reaches the cutoff potential at around the 40th cycle, and asthe cycle number increases further, the discharge capacity decreasesbelow 2500 mA h g–1 (0.25 mA h cm–2). It is reduced to 1780 mA h g–1 (0.178 mA h cm–2) at the 50th cycle. In the presence of the 3 cm2 graphene/mg g-C3N4 nanocomposite asa photocatalyst, however, the charge curves are still below the cutoffpotential and thus there is no reduction in the discharge capacityat the 50th cycle in 3N4 structure causethe Li-ion oxygen battery to have improved performance under the illuminatedconditions.The photocatalytic efficienciesof both g-C–/I3– couple (3.586 VLi+/Li) to drive redox reaction shuttling, and the CB edgepotential of the photocatalyst should be as low as possible to suppressthe charge potential. This work shows that in addition to the thermodynamicconstraints, increased conductivity, surface area, and light absorptioncapability are required for the photocatalyst to effectively reducethe charge potential under photoassistance, especially at the highcurrent densities.Effective photo-assisted charging requires a photocatalystwithimproved properties. Thermodynamically, the VB edge potential of thephotocatalyst should be greater than the redox potential of the I43N4/graphene, whichwas initially synthesized by CVD, nanocomposites were synthesizedby thermal reduction as the photocatalysts for the photo-assistedcharging of the Li-ion oxygen battery. Optical characterizations showedthat the presence of graphene reduced the optical band gaps of thenanocomposites and improved the visible light utilization of g-C3N4. The positive contribution of the graphene filmsto the photocatalytic efficiency of g-C3N4 wasalso observed in the photo-assisted charging tests of the Li-ion oxygenbattery that the charging potential was reduced considerably evenat the high charging current densities.In conclusion,the g-C


In this study, graphite, graphene, and hydrophilic-treated graphene electrodes were evaluated in a dual-chamber microbial fuel cell (DC-MFC). Free-oxygen conditions were promoted in anodic and cathodic chambers. Hydrochloric acid at 0.1 M and pH 1.1 was used as a catholyte, in addition to deionized water in the cathodic chamber. Domestic wastewater was used as a substrate, and a DuPontTM Nafion 117 membrane was used as a proton exchange membrane. The maximum power density of 32.07 mW·m Domestic wastewater contains a high level of organic compounds that store chemical energy, and with proper treatment, this energy can be harnessed . Microbirm water . Energy Some strategies to maximize the benefits of DC-MFCs focus on user-controllable parameters such as electrode materials, substrate, catholyte, and device scale ,5,6. TheGraphene is a material that has recently been used as anode and cathode in MFCs. Since its isolation in 2004, it has stood out for its unique properties. Graphene can be produced from graphite as the raw material, and then it is considered a low-cost material . Its structure is a two-dimensional (2D) cohesion of carbon atoms, with a crystalline arrangement similar to a honeycomb. It can be found in nature in the form of powder or flakes . This chctively) ,10,11, tThe catholyte is another user-manipulable parameter, which influences the electron transfer, the participation of different final electron acceptors, and the reduction potential. Oxygen is the most widely used electron acceptor due to its unlimited availability and high standard redox potential. However, it is also a limiting factor in the performance of MFCs because it can have low oxygen reduction kinetics. To address this limitation, different catholytes with a higher redox potential that facilitate the availability of other electron acceptors have been used. Examples of these catholytes are ferricyanide, sodium hypochlorite (NaOCl), sodium bromate, and hydrochloric acid (HCl) ,13,14,15To date, significant progress has been made in MFCs, however, there are still gaps to be addressed in order to improve energy efficiency and simultaneously the capacity to treat wastewater. Therefore, the objective of this work is to evaluate different carbon-based materials and the use of HCl acid as a catholyte to enhance the capacity of DC-MFCs to generate electricity and treat domestic wastewater and highlight the importance of identifying the optimal operating parameters, which directly influence MFC performance. For this purpose, three different carbon-based materials, graphite, graphene, and hydrophilic-treated graphene (HTG), were evaluated as electrodes in DC-MFCs. Additionally, HCl was evaluated as a catholyte, aiming to elucidate its influence on the catalytic properties of the cathodic chamber and to improve the degradation of organic matter in domestic wastewater. Furthermore, anoxic conditions were promoted in the anodic and cathodic chambers. Simultaneously, a control was run using the same electrode materials and under typical MFC operating conditions (deionized water in the cathodic chamber).The carbon-based materials used as electrodes were characterized by scanning electron microscopy (SEM) and Zeiss Evo ma24 energy dispersive X-ray spectroscopy (EDS) with a Bruker xflash6|10 detector, . The specific surface area and pore structure of the electrode materials were obtained with a Quantachrome Autosorb iQ tpx  by measuring the nitrogen . The membrane was activated before being used following the procedure described by Lavorante et al. . J. J−1 CODctrolyte  also repIn addition, the HTG electrodes exhibited the maximum power output in DC-MFC, compared to the untreated graphene, and graphite electrodes. This can be attributed to the fact that the Ti depositions on the HTG participate as optimizers of graphene features including electrical conductivity and the surface area of the material, as confirmed in the previous Few studies have reported the use of a low-pH environment in MFCs: Jannelli et al.  evaluatei et al.  evaluateutral pH ,49,50. THence, the use of HTG or graphene as electrodes, both operated under acidic conditions (HCl as catholyte), stand out as the scenarios that best favor energy production in DC-MFCs. Regarding the efficiencies obtained in scenarios 2 and 3 to degrade the organic matter in the wastewater, it is suggested to analyze new scenarios with a lower concentration of HCl as the catholyte. The aim is to take advantage of the benefits to produce electrical energy, and at the same time decrease the possible adverse effects on the electrogenic microorganisms and increase the capacity to oxidize the substrate.This study evaluated three electrode materials ) in DC-MFC in the capacity of treating 3.40 L of domestic wastewater and using HCl  as a catholyte, and deionized water in the cathodic chamber. A comparison of electrode materials, taking into account both their ability to produce energy and to treat wastewater, ranked them from highest to lowest performance in the following order: HTG, graphene, and graphite using HCl as catholyte. According to the characterization of the HTG material, a larger surface area, large pore volume, and higher electrical conductivity were observed, which can be attributed to the Ti deposition found on its surface. These properties in the HTG promoted the availability of active sites and, in turn, the availability of improved adhesion of the electrogenic microorganisms, resulting in the better overall performance of the DC-MFCs. In the scenario with HTG electrodes, HCl as catholyte, and an external resistance of 100, the maximum power density of 32.07 mW·m


Molybdenum trioxide–induced compressive strain in graphene increased up to −0.6% with increasing molybdenum trioxide thickness. The asymmetrical band distortion of molybdenum trioxide–deposited graphene at the Fermi level led to in-plane electrical anisotropy with a high conductance ratio of 1.43 owing to the strong interlayer interaction of molybdenum trioxide–graphene. Our study presents a symmetry engineering method to induce anisotropy in symmetric two-dimensional (2D) materials via the formation of asymmetric superlattices with epitaxially grown 2D layers.van der Waals (vdW) epitaxy can be used to grow epilayers with different symmetries on graphene, thereby imparting unprecedented properties in graphene owing to formation of anisotropic superlattices and strong interlayer interactions. Here, we report in-plane anisotropy in graphene by vdW epitaxially grown molybdenum trioxide layers with an elongated superlattice. The grown molybdenum trioxide layers led to high p-doping of the underlying graphene up to  3 on graphene induces in-plane conductance anisotropy as well as high strain, doping, and carrier mobility.Epitaxially grown MoO Meanwhile, the graphene was highly p-doped (p = 1.94 × 1013 cm−2) by the charge transfer from MoO3 regardless of the MoO3 thickness. Notably, MoO3-deposited graphene exhibited in-plane anisotropy (conductance ratio of 1.43) in the electrical conductance owing to the crystal orientation–related periodic potentials by MoO3, maintaining a high carrier mobility of 8155 cm2 V−1 s−1. Our study shows that vdW epitaxial interface can induce the strong interlayer interaction and in-plane anisotropy, which can be used to modulate the crystal orientation–dependent properties of 2D materials.Here, we report the in-plane anisotropy in graphene induced by the strong interlayer interaction with vdW epitaxially grown α-MoO3 (Pnma space group) with in-plane anisotropic mechanical, electrical, and optical properties  were stacked along the b axis with weak vdW forces  (3-grown monolayer graphene (MoO3/Gr). 3/Gr samples. Two main Raman peaks of MoO3 can be observed at ~817 and ~ 995 cm−1, corresponding to the stretching modes of doubly coordinated oxygen along the a axis (3 growth (3. This indicates that the deposited MoO3 induced doping and strain in the underlying graphene. This is discussed later in the paper. The morphology and thickness of MoO3 were measured using atomic force microscopy (AFM), as shown in 3 (2L-MoO3) with a few thick islands, as reported previously (fig. S1)  . The TEM image in 3/Gr transferred onto a TEM grid with holes, where 2L-MoO3 is partially grown on the graphene. The high-resolution TEM image in 3 on the graphene. The diffraction pattern obtained by fast Fourier transform (FFT), shown in the inset of 3 is aligned with the hexagonal pattern (orange dashed line) of graphene. The (200) plane of MoO3 is parallel to the 3 (right) in 3 unit cells with lattice parameters of 3.97 and 3.75 Å on the graphene with an epitaxial relationship: a and c axes of MoO3 are parallel to the armchair (ac) and zigzag (zz) directions of graphene, respectively. The atomic model in 3/Gr heterostructure with an epitaxial relationship. The long superlattice unit cell in MoO3/Gr can induce distinct periodicities along two directions of ac and zz in graphene , as shown in 3 after epitaxial growth. Although the uncovered graphene had no MoO3, there was a blue shift in the G and 2D peaks owing to the annealing effect  and strain (ε) of MoO3/Gr, we marked the positions of the G (ωG) and 2D (ω2D) peaks in the correlation plot of G and ω2D to the doping concentration (magenta) and strain axes (gray), respectively (fig. S2) (p = 7.8 × 1012 cm−2) with a small compressive strain of −0.07% after the MoO3 growth process, which is due to the conformal contact of graphene on the SiO2 substrate by annealing under ambient condition  regardless of the MoO3 thickness, while the compressive strain increases with the number of MoO3 layers. Different MoO3 thickness dependence of the doping concentration and strain can be clearly visualized in 3 regions of different thicknesses were deposited on the graphene, as shown in the AFM image of 3 layers, as shown in 3 epilayers resulted in a higher compressive strain, as shown in To separately measure the doping concentration  at a fixed polarizer (θin) . 3/Gr measured at four specific angles. The G peaks were deconvoluted into two peaks of G+ (red area) at 1621.7 cm−1 and G− (blue area) at 1623.2 cm−1, which have eigenvectors parallel and orthogonal to the strain direction, respectively (fig. S3)  and G− (blue circles) are plotted in polar coordinates in 2 θout patterns that repel each other in accordance with theoretical predictions (solid lines in 3 generates an anisotropic strain in graphene (The formation of an elongated superlattice and strong interlayer interaction at the MoO3/Gr device. The inset of 3 island. IDS-VG) measured with different electrodes at specific angles, indicating a highly p-doped MoO3/Gr, as observed in the Raman measurement. In addition, the current levels and slopes of the transfer curves strongly depend on the measured orientation. VG = 0 V, conductance (G), and field-effect mobility (μFE) of MoO3/Gr in polar coordinates. The p-doping concentration was calculated using the equation 0, εr, VCNP, e, and tox are the vacuum permittivity, relative permittivity of SiO2, charge neutrality point of the MoO3/Gr device, elemental charge, and thickness of SiO2, respectively. The doping level showed no orientation dependence because the doping of graphene was generated by the charge transfer between MoO3 and graphene  was 1.43 at VG = 0 V, which is comparable to that of a representative in-plane anisotropic 2D material, black phosphorus (~1.5)  of 1.77, maintaining a high mobility of 8155 cm2 V−1 s−1 at p = 1 × 1012 cm−2. This result shows that in-plane electrical anisotropy can be achieved by epitaxially grown MoO3 even in symmetrical graphene with isotropic Dirac cones at K and K′ points of the Brillouin zone (BZ) . Note that the vdW epitaxially grown MoO3 led to a high p-doping concentration of graphene without substantial degradation in the carrier mobility. As a result, MoO3/Gr shows low sheet resistance of ~133 ohms per square (figs. S5 and S6). Although the contact resistance of the MoO3/Gr is reduced by doping compared to graphene device, influence of contacts on the conductivity of MoO3/Gr was excluded because of small values (fig. S7).We also measured the angle-resolved electrical transport in the 1L-MoOgraphene . In cont3/Gr, we performed first-principles calculations based on density functional theory (DFT). Anisotropic periodic potentials on graphene cause anisotropic deformation of its band structure  and graphene (15 × ac + 3 × zz) was constructed by minimizing the mismatch between the lattice parameters of MoO3 and graphene and by applying orientation dependent TECs for MoO3 and graphene , the MoO3-deposited graphene was corrugated with a maximum out-of-plane displacement of 0.09 Å. The carbon atoms that were aligned  with the terminal oxygen atoms of MoO3 were relocated below (above) the mass center of the graphene layer. The upward and downward displacements of the carbon atoms in graphene are indicated in red and blue, respectively. Because of the atomic arrangement, graphene exhibited a 1D-like corrugation parallel to the zz direction, and the periodicity of the corrugation corresponded to the length of the superlattice.To verify our hypothesis, we constructed a MoO3 and graphene. In the supercell geometry, the electronic energy bands fold into small BZ of the cell so that the modifications of Dirac energy bands of graphene are hardly noticeable. To avoid this, we projected or unfolded the dense energy bands in the supercell BZ into the original BZ of graphene (3/graphene heterostructure (fire contour) along two directions of x (ac) and y (zz), shown in EF; gray dashed lines) is downshifted by ~0.7 eV below the Dirac point of graphene, which supports our experimental observation of high p-doping concentration of graphene by the deposition of MoO3. We also compared the band structures of the isolated graphene layer (green dashed lines), which had the same compressive strain as the MoO3/graphene heterostructure. We noted that the apparent gapful (gapless) Dirac point along xq (yq) direction in yq direction. The effective band structure along the y axis on the right side of x axis on the left side of 3 layer. It is estimated that the directional electronic difference shown in 3/graphene heterostructure.The directional corrugation of graphene results in periodic potentials on graphene depending on the distance between MoOx and y axes could be estimated using the Boltzmann transport equation under a simple constant relaxation time (τ) approximation (α) is given byvαn,k, εn,k, τ, and f are the α-directional component of k-dependent group velocity, energy of the nth band, relaxation time (considered a constant for simplicity), and Fermi distribution function as a function of the energy (ε), chemical potential (μ), and temperature (T), respectively. As shown in y axis is lower than that along the x axis around the Fermi level, consistent with our experimental results. Although the simulation results partly support observed anisotropic conductance originated from structural disparities for two orthogonal directions, the obtained anisotropy is still smaller than the measurement. We may consider further detailed characteristics reflecting actual experiment situations, such as larger supercell geometries and different scattering times along the direction, to improve the simulation results later.On the basis of these band structures, the conductivities (σ) along the 3 epilayers and monolayer graphene growth templates in the symmetry-mismatched epitaxy. Our results demonstrated that the extreme modulation of doping and strain in graphene was generated by the strong interlayer interaction with the MoO3 epilayers. First, the hole concentration in graphene could be markedly increased by the deposition of a single layer of MoO3. Our results were comparable with those obtained using other similar doping methods (deposition of a charge-transfer layer on graphene) /Si substrate using an e-beam evaporator or a DC magnetron sputter. The quality and morphology of MoO3 were irrelevant to the metal deposition method. As the target substrate, graphene was mechanically exfoliated on another SiO2/Si substrate. Only monolayer graphene flakes were selected and used as target templates after their thicknesses were identified using Raman spectroscopy. To synthesize MoO3 on monolayer graphene, the Mo film was placed on a preheated heater (525°C), and, shortly after, the target substrate was located 0.5 mm above the Mo film upside down. The Mo film was oxidized and sublimated into MoOx and condensed on the graphene-exfoliated substrate because of the temperature difference between the source and target substrates. After 10 min, the target substrate was immediately removed from the heater. The thickness and coverage of MoO3 could be roughly controlled by varying the deposition time.A MoO−1) and detected by a liquid nitrogen–cooled back-illuminated charge-coupled device detector. The laser power was kept below 0.1 mW. The polarizer was fixed at constant angle (θin), and the analyzer angle (θout) was rotated to select specific polarization of the scattered light. An achromatic half-wave plate was placed in front of the spectrometer to keep the polarization direction of the signal entering the spectrometer constant with respect to the groove direction of the grating.Raman spectra were acquired using a Raman spectroscope . Angle-resolved polarized Raman measurements were performed using a home-built confocal micro-Raman system with excitation sources of the 2.33 eV (532 nm) line from a diode-pumped solid-state laser. A 50× objective lens  was used to focus the laser beam onto the sample and collect the scattered light (backscattering geometry). The Raman signal was dispersed using a Jobin-Yvon HORIBA iHR550 spectrometer (2400 grooves mm3/Gr was transferred to a holey carbon Au TEM grid using a poly(methyl methacrylate) (PMMA)–based transfer method. PMMA was spin-coated on the SiO2/Si substrate where MoO3/Gr was located and immersed in a 2 weight % KOH solution after scouring the edges of the substrate. The PMMA/MoO3/Gr film floated on the solution because SiO2 was etched by KOH. The film was rinsed with deionized water several times and transferred onto a holey carbon Au TEM grid, and PMMA was removed by placing the TEM grid in acetone overnight. High-resolution TEM images were captured using a Cs-TEM (JEOL JEM-ARM 200F Cs-TEM).MoOAFM images were measured using NX-10 (Park Systems). Both contact and noncontact modes were performed considering the status of the samples and environment.3/Gr. Subsequently, Cr/Pd/Au (2 nm/30 nm/40 nm) was deposited on MoO3/Gr using an e-beam evaporator. The electrical measurements of the devices were performed using a parameter analyzer (Keithley 2400) under ambient conditions. The two-probe field-effect mobility (μFE) of MoO3/Gr was calculated using the following equationc is the unit back-gate capacitance of 285-nm SiO2, gm = dIDS/dVG is the transconductance, VDS is the drain voltage, and L and W are the channel length and width, respectively. The channel width is defined as the width of the metal electrodes. The transconductance was obtained by linearly fitting the transfer curve.e-beam lithography was performed to define the patterns of the source and drain electrodes surrounding MoO3/graphene heterostructure, we performed first-principles calculations based on DFT (−1. Dipole correction was included for a more precise calculation. For the exchange-correlation function, the rev-vdW-DF2 method (k-grid for the rectangular supercell of MoO3/graphene. To avoid spurious interlayer interaction along the out-of-plane direction, a vacuum region of 15 Å was introduced.To investigate the electronic and transport properties of the MoO


The opioid crisis is a worldwide public health crisisthat hasaffected millions of people. In recent years, synthetic opioids, primarilyillicit fentanyl, have become the primary driver of overdose deaths.There is a great need for a highly sensitive, portable, and inexpensiveanalytical tool that can quickly indicate the presence and relativethreat of fentanyl. In this work, we develop a semiconductor enriched(sc-) single-walled carbon nanotube (SWCNT)-based field-effect transistor(FET) biosensor functionalized with norfentanyl antibodies for thesensitive detection of norfentanyl, the primary inactive metaboliteof fentanyl, in urine samples. Different sensor configurations wereexplored in order to obtain the most optimized sensing results. Moreover,by employing the “reduced” antibody, we achieved orientatedimmobilization of the norfentanyl antibody and thus brought the antigen–antibodyinteraction closer to the sensor surface, further improving the sensitivity.The reported norfentanyl biosensors have a limit of detection in thefg/mL region in both calibration samples and synthetic urine samples,showing ultrasensitivity and high reliability. N-phenyl-N-[1-(2-phenylethyl)piperidinyl]-propanamide)is a potent synthetic opioid that is used as a pain reliever and an anesthetic. It is approximately 50–100 times more potentthan morphine.1 However, due to its pharmacologicaleffects, the overdose of fentanyl can cause difficulties in breathingand can lead to death. According to the U.S. Centers for Disease Controland Prevention (CDC), synthetic opioids are the primary driver ofoverdose deaths in the United States, making opioid overdose deathsa major public health crisis.3 At the same time, fentanylcan also be found in combination with other drugs such as heroin orcocaine. Therefore, there is a great need for a highly sensitive,portable, and inexpensive analytical technique that can quickly indicatethe presence and relative threat of fentanyl.Fentanyl  via hydrolysis.15 Laboratories often combine chromatographic methods with immunoassaysto ensure both high sensitivity and specificity.17 However, these techniques require specialized equipment and training,making them relatively expensive and time-consuming. Meanwhile, dueto the lack of redox activity of norfentanyl, certain electrochemicalmethods, although are generally considered to be rapid, simple, andlow-cost, are not suitable for norfentanyl detection.19Instrumental analyticalmethods, such as gas chromatography–massspectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry(LC-MS/MS) are the most commonly used techniques for the detectionof norfentanyl.25 Previously, an aptamer-based graphene FET (AptG-FET) platform wasreported for the simultaneous detection of three different opioidmetabolites in wastewater.26 The AptG-FETplatform with a coplanar Pt gate enabled multianalyte detection ona single chip and achieved a picogram per milliliter level limit ofdetection for noroxycodone (NX), 2-ethylidene-1,5- dimethyl-3,3-diphenylpyrrolidine(EDDP), and norfentanyl. Semiconductor-enriched (sc-) single-walledcarbon nanotubes (SWCNTs), on the other hand, are particularly promisingcandidates for FET biosensors because the high-purity semiconductingcontent offers high on/off ratio for FETs,27 facilitating ultrasensitivity of sc-SWCNT-based FET biosensors.29 Additionally, due to the presence of functional groups on the sidewalls,SWCNTs provide more avenues for functionalization with custom-designedchemistry to preferentially interact with target biomolecules, whichleads to excellent sensitivity in complex media, such as saliva,30 sweat,31 and serum.32Carbon nanomaterial-based field-effect transistor (FET) biosensorshave shown remarkable sensitivity and low detection limits for a varietyof biological analytes.This work aims to develop a functionalizedcarbon nanotube-basedbiosensor for ultrasensitive norfentanyl detection in body fluidsand consequently make time-sensitive decisions. Here, we report anorfentanyl antibody-functionalized sc-SWCNT-based FET biosensor thatachieved fg/mL level limit of detection of norfentanyl in both calibrationsamples and synthetic urine samples. To optimize the detection inthe sensing matrix, we explored different approaches for the attachmentof antibody on sc-SWCNTs, namely, the direct coupling approach andgold nanoparticle (AuNP) approach, and different biorecognition elementsfor the detection of norfentanyl. Distinct sensing behaviors wereobserved during the sensing experiments, implying different sensingmechanisms with different sensor configurations. By analyzing thesensing performances, we found that the AuNP-decorated sc-SWCNT FETbiosensors provide a more robust platform for antibody functionalizationand are less susceptible to nonspecific species present in biologicalsamples, making them good candidate for point-of-care tool for thedetection of fentanyl exposure. Moreover, we successfully appliedour sensor fabrication with a flexible FET electrode and demonstratedgood sensing performances for norfentanyl detection with a portablesensing setup.As shown in Id–Vg curve after the addition of the blocking buffer .Raman spectroscopy was utilized to understand the effect of antibodyfunctionalization on the structure of SWCNTs. Although no prominentpeaks from the antibody were observed after the direct coupling ofthe antibodies, the analysis of the D and G features from sc-SWCNTsreveals an increase in the ID/IG ratio from 0.051 to 0.11, suggesting an increasein the degree of functionalization of SWCNTs, likely due to the covalentbonding of antibodies to the SWCNTs .37 Raman intensityof sc-SWCNTs increased about 20 times due to the SERS effect. Moreimportantly, Raman features from the norfentanyl antibody, which aregenerally hard to resolve at low concentration, appear in the Ramanspectra . The norfentanyl antibody-functionalizedsc-SWCNT FET biosensor responses were investigated by employing aliquid-gate FET configuration and recording FET transfer characteristics(Id–Vg), from which rich information about the biorecognition process,sensing mechanism, and sensing performances can be extracted. TheFET transfer characteristics were measured using a portable dual-channelpotentiostat to enable norfentanyl detection on site. Standard resistortests suggest that no significant difference is observable betweenthe portable potentiostat and laboratory high precision sourcemeters. The latter were used in ourprevious SWCNT-based FET biosensor work.40 Moreover, itis worth mentioning that albeit direct FET measurements in norfentanylsamples simplify the sensing procedure and facilitate real-time sensing,the high ionic strength of phosphate buffered saline (PBS) or syntheticurine causes Debye screening and lowers sensitivity . As a result, all FET characteristics were recordedin 0.001× PBS after sample incubation to overcome the Debye screeninglimitation.While fentanyl, as a redox active molecule, can be detected usingelectrochemical methods such as cyclic voltammetry, differential pulsevoltammetry (DPV), and square wave voltammetry (SWV), no redox activitywas found for norfentanyl when we conducted cyclic voltammetry studieswith norfentanyl using sc-SWCNTs as the working electrode . The calibration curve also provides information about the bindingaffinity between norfentanyl and its antibody at the sensor interface.The dissociation constant (Kd), whichcorresponds to the concentration at half-maximum response, is 2.8fg/mL for sensors adopting the direct coupling approach and 2.0 pg/mLfor AuNP-decorated sensors.41The sensor responses at different norfentanyl concentrationsareplotted in 31 Similarly, the binding between norfentanyl and norfentanyl antibodylikely relies on the nonpolar hydrogen−π interactionand cationic-π interaction between norfentanyl and amino acidresidues inside the binding sites of the antibody such as aspartate(Asp) and tyrosine (Try).42 Therefore,we attributed the sensor response to the redistribution of chargeson the antibody upon norfentanyl binding, making the antibody lesspositively charged and consequently p-doping the sc-SWCNTs.Despite both types of devices demonstrating sensingcapabilitiestoward norfentanyl with an LOD in the fg/mL region, the calibrationcurves displayed opposite trends upon norfentanyl exposure. For devicesadopting the direct coupling approach, the binding of norfentanylon the device surface induced an increase in the conductance of theFET device, resulting in a corresponding increase in the relativeresponse. This result is consistent with what we previously observedwith cortisol antibody-functionalized sc-SWCNT FET biosensors forcortisol sensing utilizing the same approach.43When decorated with AuNPs, norfentanyl antibodies predominantlybound to the AuNP surfaces; thus, the AuNP-nanotube interface is mostresponsible for the sensing. At the junction of metal nanoparticlesand semiconductors, Schottky barriers form. Upon binding of norfentanyl,the charge redistribution of the norfentanyl antibody lowers the workfunction of the AuNPs, increasing the Schottky barrier, and as a result,a decrease in the conductance was observed in the experiment.Figure S6). In terms of selectivity, other opioid metabolites,namely, normorphine (the metabolite of morphine), norhydrocodone (themetabolite of hydrocodone), and 6-acetylmorphine (indicative of heroinuse), were added to the norfentanyl ab-Au-sc-SWCNT FET biosensorsin the same concentration range as norfentanyl. However, the sensorbehaviors are markedly different . It is less likely that theantigen–antibody interaction is impaired because of two reasons:(1) the ionic strength of the synthetic urine is similar to that ofPBS, which is optimal for antigen–antibody binding; and (2)while high concentration of urea (∼6 M) can be used for thedissociation of antigen-bound antibody, the urea concentration isrelatively low (∼250 mM) in synthetic urine.45 With a higher extent of dilution, the interactions between the interferingspecies and the carbon nanotubes became negligible, and the specificsensor response restores. On the opposing side, for devices decoratedwith AuNPs, fewer carbon nanotube surfaces are exposed to the biologicalenvironment, therefore demonstrating less susceptibility to interferences.The compromised sensitivity of the sensors fabricatedvia the directcoupling approach is likely due to the interactions between the nonspecificspecies present in the synthetic urine with the carbon nanotubes.By immersing the FET devices in 1× synthetic urine without norfentanylfor 10 min, it is evident that the nonspecific species in the syntheticurine can alter the FET characteristics of both types of devices . As a result, a collective effectof the specific and nonspecific interactions leads to an increasein the calibration sensitivity of both sensors in 1000-fold dilutedsynthetic urine. The comparison of the sensor performances in PBSand 1000-fold diluted synthetic urine reveals a 55.6% rise in calibrationsensitivity for devices with directly coupled antibodies and a 55.2%rise in calibration sensitivity for devices decorated with AuNPs . However, in order to improve thequantitative ability of the sensors, in real-life practices, backgroundelimination should be considered when applying this biosensor forthe detection of norfentanyl in clinical samples.Interestingly, both types of sensors respond to the nonspecificsynthetic urine components in a similar way as to norfentanyl . Although no obvious sulfur(S) peak is shown in the survey spectrum, peaks associated with Au(I)appear in high-resolution XPS spectra of Au 4f of the device . We therefore attributed the peaksto the covalent bonding between AuNPs and the free thiol terminalscreated by reducing the antibody,52 which confersthe control over the orientation of the antibodies on the sensor surface.AFM characterization of the AuNP-sc-SWCNTs before and after the incorporationof reduced antibody reveals an average of 5.02 nm increase in theheight of the nanoparticles , significantly lower than the 10.6 nm increase by attaching wholeantibody. This result provides further evidence that by employingreduced antibodies, the antigen–antibody interaction can bebrought closer to the sensing surface.The binding between the reduced antibody and theAuNPs was analyzedby XPS. Peaks corresponding to carbon (C), nitrogen (N), oxygen (O),gold (Au), and silicon (Si) can be found on the XPS survey spectrum,confirming the presence of the reduced antibodies on Au-sc-SWCNTs. The sensor performance was evaluated using the calibrationcurve based on the relative current change at −0.1 Vg. The calibration sensitivity was then determinedto be 0.063, which is comparable to the laboratory-fabricated sensors.In order to enhance the practicalityof our developed norfentanylsensor, we implemented our sensor fabrication technique on commerciallyavailable electrodes for better integration with a portable potentiostat.First, sc-SWCNTs were drop-cast on an interdigitated gold electrodeon a glass substrate with 10 μm channels (G-IDEAU 10), and norfentanylantibodies were attached to the CNTs via direct coupling. The selectionof the electrode was based on its similarity in sensor geometry tothe sensors fabricated in the laboratory . The patterned gold gate on the AUFET eliminates theneed for a separate gate electrode and fixes the distance betweenthe gate electrode and the semiconducting channels, providing a morecontrolled sensor configuration 6a. As a 57 The gold gate, which is 3 ×3 mm in size, provides a large surface area for spontaneous bindingof norfentanyl antibodies. Upon addition of norfentanyl, the conductanceof the device increases. The sensor calibration made by plotting therelative responses at applied gate voltage of −0.5 V againstnorfentanyl concentration validates the norfentanyl sensing effectof the AUFET sensor . The IDEs were patternedon the substrate using photolithography, forming 10 μm channels.Semiconducting single-walled carbon nanotubes  were prepared at 0.02 mg/mL in toluene and depositedbetween gold electrodes via dielectrophoresis (DEP) with an ac frequencyof 100 kHz, applied bias voltage of 10 V, and bias duration of 120s. The devices were annealed at 200 °C for 1 h before use.The 2.6 × 2.6 mm sensor chipwas fabricated on a Si/SiON-hydroxysulfosuccinimide (sulfo-NHS) solutionfor 30 min to activate the carboxylic acid groups. Norfentanyl antibody was then introduced onthe sc-SWCNTs surface directly after activation and incubated overnightat 4 °C.For FET devices fabricated via the direct coupling approach, thesc-SWCNTs were first incubated in a 50 mM/50 mM 1-ethyl-3-(3-(dimethylamino)propyl)carbodiimide(EDC)/4 solution (1 mMin 0.1 M HCl). The deposition voltage was set at −0.2 V andapplied for 30 s. Norfentanyl antibody solution was then immobilizedon the device surface by an incubating overnight at 4 °C.For FET devices fabricated via the gold nanoparticle(AuNP) approach,gold nanoparticles were deposited on sc-SWCNTs via bulk electrolysisusing a CH Instruments electrochemical analyzer in a three-electrodesetup  from a HAuClAfter the attachment of norfentanyl antibody, a blocking buffer(0.1% Tween 20 and 4% poly(ethylene glycol) in PBS) was applied tothe device surface to block unreacted surfaces.2 chip using a ZEISSSigma 500 VP instrument.Scanning electronmicroscopy was performed on a Si/SiOAFM data were collectedusing a Bruker multimode 8 AFM system with a Veeco Nanoscope IIIacontroller in tapping mode. AFM image and height profiles were processedand obtained in Gwyddion.X-ray photoelectronspectroscopy data was generated on a Thermo ESCALAB 250 Xi XPS instrumentusing monochromated Al Kα X-rays as the source. A 650 μmspot size was used, and the samples were charge compensated by usingan electron flood gun.Raman characterization of the deviceswas performed by using a XplorA Raman-AFM/TERS system. Radial breathingmode (RBM) region was recorded using a 785 nm (100 mW) excitationlaser operating at 1% power. D and G peak regions were recorded using638 nm (24 mW) excitation laser operating at 1% power.Norfentanyl sensing using sc-SWCNT-basedFET biosensors via cyclic voltammetry was conducted by using a CHInstruments electrochemical analyzer. A three-electrode configurationwas used, where sc-SWCNT acted as the working electrode, Ag/AgCl electrodewas used as the reference electrode, and Pt wire was used as the auxiliaryelectrode. The CV experiments were performed by sweeping the voltagefrom −0.6 to +0.6 V for 10 cycles with a scan rate of 20 mV/s.Id) wascollected by sweeping the gate voltage (Vg) from +0.6 V to −0.6 V while keeping the source-drain voltageat 50 mV. The gating media was 0.001× PBS.A Metrohm DropSens μStat-i 400potentiostat was used for all of the FET measurements. FET transfercharacteristics were measured by employing a liquid-gated FET deviceconfiguration. A 1 M Ag/AgCl reference electrode was used as the gateelectrode. Source-drain current . For synthetic urine samples, 1× syntheticurine was first prepared according to For each device, FET transfer characteristicswere first collectedin a blank sample, which would be used as a baseline. Next, 10 μLof each norfentanyl sample was added to the surface of the deviceand the mixture incubated for 10 min. After the incubation, the devicewas rinsed with nanopure water to remove the unbound sample, and FETtransfer characteristics were collected in the gating medium in orderto keep the same ionic strength for all FET measurements.R) of each FET device wascalculated as R = ΔI/I0 at Vg = −0.5V, where ΔI = Id – I0, and I0 is the drain current in blank sample (baseline) before analyteexposure at applied gate voltage of −0.5 V. The calibrationcurve was plotted by reporting the averaged relative conductance ofall devices tested with standard error as error bars at each concentration.The number of devices (n) tested for each experimentis specified in the figure. Calibration sensitivity was defined asthe slope of the linear region on the calibration curve. The linearregion was located by fitting the calibration curve using a Logisticmodel.Therelative response  and taken FET measurementsfor 5 times after the initial blank measurement. The relative changeat each test was calculated, and δ was determined from the 5tests.The limit of detection was calculated using the formulaLOD = 10The reaction bufferwas prepared by adding 10 mM ethylenediaminetetraacetic acid (EDTA)to 1× PBS. Six milligrams of 2-mercaptoethylamine·HCl (2-MEA)was dissolved in 100 μL of Reaction Buffer, and then 5 μLof this 2-MEA solution was immediately added to 50 μL of norfentanylantibody solution (1.03 mg/mL) in PBS. The reaction mixture was keptin an incubator at 37 °C for 90 min. After the reaction, bufferexchange was performed using a desalting column to remove 2-MEA fromthe reduced antibody. The final solution with the reduced norfentanylantibody was aliquoted and frozen for further use.


Staphylococcus aureus (SA) infections, both methicillin-susceptible and methicillin-resistant , cause significant morbidity among infants in neonatal intensive care units (NICU). Colonization usually precedes infection. We studied the molecular epidemiology of SA colonization in NICU infants using whole genome sequencing (WGS) and in relation to the opening of a new NICU with single-family rooms.From 2019-22, a prospective cohort of infants admitted to the Level IV NICU at Mayo Clinic, Rochester, MN was screened twice weekly for SA colonization using cultures of nares/axilla/groin swabs. Infection control procedures were consistent throughout, including use of Contact Precautions for infants colonized with MRSA but not for MSSA. The study was divided into period 1 (1/1/2019-11/30/2020) and period 2 (12/1/2020-12/31/2022) due to a move from a 34-bed unit (26 beds in four open-bay rooms and 8 beds in single-family rooms) to a new 34-bed unit . WGS was performed using Illumina MiSeq instrumentation and chemistry with Illumina Nextera XT library chemistry. Assembly and core genome multilocus sequence typing analysis were performed with Ridom SeqSphere+ software. Groups of related isolates were identified based on the number of allelic differences . Groups of MRSA-related isolates were compared with reference USA genotypes. Chi square tests did not adjust for clustering.There were 663 admissions in period 1 and 730 in period 2. The prevalence of MSSA and MRSA colonization was unchanged in the two periods . By WGS, most MSSA and MRSA isolates were unrelated to another isolate in both periods (Table). Groups of related MSSA and MRSA isolates differed between the two periods and the number of isolates/group was small (< 6 isolates). Groups of related MRSA isolates were associated with reference genotypes USA100 (period 1), USA1000 (periods 1 & 2), and USA300 (period 2).WGS Results for MSSA and MRSA in Periods 1 and 2NICU infants were usually colonized with unrelated strains of MSSA and MRSA, with only small clusters of related strains. The new NICU was not associated with a change in MSSA or MRSA colonization.Priya Sampathkumar, MD, Merck Vaccines: Advisor/Consultant Robin Patel, MD, Abbott Laboratories: Advisor/Consultant|Adaptive Phage Therapeutics: Grant/Research Support|Adaptive Phage Therapeutics: Mayo Clinic has a royalty-bearing know-how agreement and equity in Adaptive Phage Therapeutics.|BIOFIRE: Grant/Research Support|CARB-X: Advisor/Consultant|ContraFect: Grant/Research Support|Day Zero Diagnostics: Advisor/Consultant|HealthTrackRx: Advisor/Consultant|Mammoth Biosciences: Advisor/Consultant|Netflix: Advisor/Consultant|Oxford Nanopore Technologies: Advisor/Consultant|PhAST: Advisor/Consultant|See details: Patent on Bordetella pertussis/parapertussis PCR issued, a patent on a device/method for sonication with royalties paid by Samsung to Mayo Clinic|See details: continued, patent on an anti-biofilm substance issued|TenNor Therapeutics Limited: Grant/Research Support|Torus Biosystems: Advisor/Consultant|Trellis Bioscience, Inc.: Advisor/Consultant W. Charles Huskins, MD, MSc, ADMA Biologics: Advisor/Consultant|Bristol Myers Squibb: Stocks/Bonds|Pfizer: Advisor/Consultant|Pfizer: Stocks/Bonds|Zimmer Biomet: Stocks/Bonds


Staphylococcus aureus (MSSA) is one of the leading causes of pediatric musculoskeletal (MSK) infections, such as osteomyelitis and septic arthritis. MSSA MSK infections are treated initially with an IV antibiotic, followed by prolonged oral therapy. Cephalexin is the most used oral option due to long-standing clinical experience and its well-described pharmacokinetics (PK) in children. Cefadroxil could be an attractive alternative requiring less frequent dosing, but it has minimal pediatric clinical or PK data. In this study, we describe the comparative PK of cephalexin and cefadroxil in children with MSK infections and evaluate dosing regimens to achieve effective free time above the MIC (fT >MIC) for MSSA.Methicillin-susceptible Children aged 6 months to 18 years admitted with an MSK infection were enrolled in a prospective, open-label, crossover study and given single oral doses of cefadroxil  and cephalexin . During a single dosing interval, 4-5 plasma samples were obtained per patient for each drug. Antibiotic concentrations were quantified using liquid chromatography-mass spectrometry. PK models were developed, and then Monte Carlo simulations were performed using various dosing regimens to estimate the probability of target attainment (PTA) for a range of pharmacodynamic (PD) targets, across various pediatric ages and common MSSA MICs (1-4 mg/L).Concentration-time data for cephalexin (n=15) and cefadroxil (n=14) were best described using a one-compartment model with first order absorption. PK parameters were notable for cefadroxil’s longer half-life than cephalexin. Monte Carlo simulation showed that cephalexin 120 mg/kg/day divided q8hrs  and cefadroxil 100 mg/kg/day divided q12hrs  achieved >95% PTA for fT >MIC >40% for MICs up to 4 mg/L, though cephalexin QID and cefadroxil TID dosing were required to achieve higher PD goals.Among pediatric patients with MSK infections, oral cefadroxil and cephalexin both achieve PD targets for efficacy against MSSA. Twice-daily cefadroxil should be further considered as an alternative to cephalexin for oral step-down therapy given its similar PTA and possibility for less frequent dosing.Marc H. Scheetz, PharmD, MSc, Abbvie: Advisor/Consultant|ASHP: Honoraria|Chambless, Higdon, Richardson, Katz & Griggs, LLP: Expert Testimony|Cidara: Advisor/Consultant|Entasis: Advisor/Consultant|F2G: Advisor/Consultant|GSK: Advisor/Consultant|Guidepoint Global: Honoraria|Hall, Booth, Smith, P.C.: Expert Testimony|Merck: Advisor/Consultant|Reminger Co., L.P.A: Expert Testimony|Spero: Advisor/Consultant|Takeda: Advisor/Consultant|Taylor, English, Duma, LLP: Expert Testimony|Third Pole Therapeutics: Advisor/Consultant Sarah K. Parker, MD, Pfizer: Grant/Research Support


The prognostic role of soluble PD-L1 (sPD-L1) and exosomal PD-L1 (exoPD-L1) in patients with gastric cancer (GC) receiving systemic chemotherapy remains unelucidated. Thus, we examined their prognostic significance in patients with advanced GC. Blood samples were obtained from 99 patients with advanced GC receiving first-line chemotherapy. Serum-derived exosomes were isolated by centrifugation and polymer precipitation. The correlation between serum-derived exoPD-L1, plasma sPD-L1, immune-related markers, and circulating immune cells was evaluated. Patients were divided into two groups according to pretreatment sPD-L1 and exoPD-L1 levels: low sPD-L1 and high sPD-L1 groups, low exoPD-L1 and high exoPD-L1 groups. Patients with low sPD-L1 level before treatment (< 9.32 pg/mL) showed significantly better overall survival (OS) and progression-free survival (PFS) than those with high sPD-L1 level (≥ 9.32 pg/mL). The low exoPD-L1 group (< 10.21 pg/mL) showed a tendency of longer PFS than the high exoPD-L1 group (≥ 10.21 pg/mL). Pretreatment sPD-L1 was an independent prognostic factor for OS in multivariate analysis. exoPD-L1 was associated with systemic inflammation markers, immunomodulatory cytokines, and T cells, while sPD-L1 was associated with tumor markers. Pretreatment plasma-derived sPD-L1 level could be used as a prognostic marker for patients receiving cytotoxic chemotherapy. Serum-derived exoPD-L1 may reflect the immunosuppressive state of patients with advanced GC. Systemic chemotherapy is the mainstay treatment for advanced GC; however, the prognosis is poor5. Recently, the combination of the programmed death-1 (PD-1) inhibitor, nivolumab, with cytotoxic chemotherapy has shown survival benefits in unresectable advanced or metastatic GC and has become the standard first-line treatment for patients with a PD-L1 combined positive score (CPS) of 5 or higher6.Gastric cancer (GC) is the fifth most common cancer and the fourth leading cause of cancer-related deaths worldwide; it is especially prevalent in Eastern Asia and Eastern Europe7. The PD-L1/PD-1 axis has been found to be an important mechanism for tumor cells to evade host immunity and has been identified as a major target of cancer immunotherapy using immune checkpoint inhibitors9. The degree of PD-L1 expression in tumor and tumor microenvironment can be measured using tumor proportion score (TPS) and CPS. TPS measures PD-L1 expression in tumor cells only, while CPS measures the total number of PD-L1-positive cells, including both tumor cells and immune cells in the tumor microenvironment.PD-L1 is a membrane-bound ligand found mainly in tumor cells and microenvironmental immune cells. When PD-L1 binds to the PD-1 receptor, an immune checkpoint receptor is expressed on T cells, and it transduces an inhibitory signal that inhibits T cell activation15. Several clinical trials have found that PD-L1 expression in the tumor and tumor microenvironment has a predictive value for response to PD-1 inhibitors20. However, the temporal and spatial heterogeneity of tissue PD-L1 expression limits its prognostic and predictive value21. To address this limitation, recent studies have focused on the extracellular forms of PD-L1.Many studies have been conducted to investigate the relationship between PD-L1 expression in tumor tissues and prognosis in different cancers22. Several studies have been conducted to investigate the clinical utility of sPD-L1 in various cancers30.PD-L1 can be found in multiple extracellular forms, such as microvesicles, exosomes, and secreted or cleaved forms in the blood. Soluble PD-L1 (sPD-L1) is an extracellular form of PD-L1 that can be detected in the blood, and recent studies have shown that soluble PD-L1 retaining PD-1 binding domain could bind to the PD-1 receptor of immune cells to negatively regulate their antitumor immune response31. Exosomal PD-L1 (exoPD-L1) derived from tumor suppresses T cells and higher levels of exoPD-L1 have been associated with poor survival in different types of tumors34. exoPD-L1 has been found to be a potential biomarker for recurrence in postoperative GC patients, and it is associated with the prognosis of GC because of its potential immunosuppressive role36.Exosomes are nano-sized, lipid bilayer membrane-bound extracellular vesicles formed by the endocytic pathway and secreted following the fusion of multiple vesicular bodies with the plasma membrane. Exosomes contain proteins, lipids, and nucleic acids of the cells of origin, which are considered important mediators of intercellular communicationHowever, the prognostic role of both sPD-L1 and exoPD-L1 in patients with advanced gastric cancer receiving chemotherapy has not been thoroughly investigated. The current study aimed to investigate the prognostic and predictive significance of both sPD-L1 and exoPD-L1 in patients with advanced GC receiving first-line chemotherapy.A total of 99 patients were recruited for analysis between March 2019 and March 2021. The median OS was 12.4 months (95% CI 10.4–15.2 months). Table 37. The cut-off values of exoPD-L1 and sPD-L1 were 10.21 pg/mL and 9.32 pg/mL, respectively.The median exoPD-L1 level for all patients was 11.90 pg/mL (range: 0.02–69.87 pg/mL). The median plasma sPD-L1 level was 5.62 pg/mL (range: 0.12–23.93 pg/mL). To determine optimal cut-off values of exoPD-L1 and sPD-L1 levels, maximally selected log-rank statistics was applied to discriminate the patients into two groups in terms of OSBased on the cutoff value of exoPD-L1, patients were grouped into the high exoPD-L1 group ) and low exoPD-L1 group ). Based on the cutoff value of sPD-L1, patients were grouped into the high sPD-L1 group ) and low sPD-L1 group ).ρ = 0.306, p = 0.044) . The low sPD-L1 group also showed longer PFS than the high sPD-L1 group   . But, pretreatment exoPD-L1 was not different between PD group and PR and SD group.  in 42 patients (42.4%), stable disease (SD) in 38 patients (38.4%), progressive disease (PD) in 17 patients (17.2%), and not evaluable in two patients (2.0%). Pretreatment sPD-L1 was higher in the PD group than in the PR and SD group  and PLR  were both positively correlated with exoPD-L1, and ALC  was negatively correlated with exoPD-L1 , absolute neutrophil count (ANC), absolute lymphocyte counts (ALC), platelet count, neutrophil to lymphocyte ratio (NLR), and platelet to lymphocyte ratio (PLR). The NLR   and IFN-γ . The high exoPD-L1 group had higher levels of TGF-β1 and IFN-γ than the low exoPD-L1 group  . The high exoPD-L1 group showed a significantly lower frequency of CD8+ T cells than the low exoPD-L1 group (p = 0.021). The high exoPD-L1 group showed a higher frequency of PD-1+CD8+ T cells in CD8+ T cells than the low exoPD-L1 group , high sPD-L1 , and high NLR  were independent prognostic factors for OS , CA 19-9 (> 37 U/mL), number of metastatic sites (≥ 2), high sPD-L1, and high NLR were prognostic factors associated with OS. After adjusting for covariates, multivariate analysis showed that the number of metastatic sites (≥ 2)  of stage IV out of 69 patients and Li’s study included about 27 patients (9%) of stage IV out of 331 patients. This indicates that the prognostic value of exoPD-L1 could be more significant in earlier GC than in advanced GC. In addition, subsequent PD-1 inhibitor treatment might lead to insignificant survival difference between exoPD-L1 high and low group, although predictive role of exoPD-L1 was not established in advanced gastric cancer patients receiving PD-1 inhibitors.Several studies have compared the prognostic value of sPD-L1 and exoPD-L1 in GC. Fan et al. showed that exoPD-L1 had a better prognostic value than serum sPD-L1 in GC. Li et al. also showed that exoPD-L1 could be more prognostic by comparing exoPD-L1 with sPD-L1 in post-operative GC patients45. A study on 180 patients who underwent surgery for gastric cancer also analyzed the relationship between sPD-L1 and tissue PD-L1, but no correlation was found46. However, recent studies have revealed a correlation between sPD-L1 and tissue PD-L1 expression in colorectal cancer and hepatocellular carcinoma47. These controversial results are similarly observed for exoPD-L1, wherein studies on lung cancer and melanoma have shown a positive correlation between exoPD-L1 and tissue PD-L149, whereas others have not found a correlation51. The reasons for these controversial results could be the unclear source of extracellular PD-L1, the influence of the spatial and temporal heterogeneity of tissue PD-L1, and the difference in methods used to measure PD-L1 expression in tissue and blood. In our study, no correlation was observed between tissue PD-L1 and sPD-L1 in all patients or between the latter and exoPD-L1. However, sPD-L1 was positively associated with CPS in the high-PD-L1 expression group (CPS ≥ 10). This might indicate that patients with high CPS may have a higher proportion of sPD-L1 derived from both the tumor and the tumor microenvironment compared to other unclear sources. Thus, it is possible that the correlation between CPS and sPD-L1 may be more likely to be observed in patients with high CPS. In future studies, to elucidate the relationship between tissue PD-L1 expression and extracellular PD-L1, CPS, which measures the expression of PD-L1 in both tumor and immune cells within the tumor microenvironment, would be a more appropriate option for evaluating PD-L1 expression in tissue compared to solely measuring PD-L1 expression in cancer cells.The origin of circulating PD-L1 remains unclear and could be derived from multiple sources, including tumor cells and surrounding immune cells. The correlation between tissue PD-L1 expression and circulating PD-L1 has been investigated in previous studies; however, the results are controversial. Several studies on lung cancer, renal cell carcinoma, and melanoma have shown that there is no correlation between sPD-L1 and tissue PD-L132. This lack of a correlation may suggest that they serve different biological roles. In our study, both exoPD-L1 and sPD-L1 showed correlations with different factors. Considering that sPD-L1 showed potential prognostic value for advanced GC and that exoPD-L1 might be associated with the host immunosuppressive status, further research into the prognostic and predictive value of both sPD-L1 and exoPD-L1 for patients with GC receiving PD-1 inhibitors alone or in combination with cytotoxic chemotherapy is required.In our study, exoPD-L1 did not show a clear correlation with sPD-L1, which is similar to the results of previous studies on head and neck cancer and colorectal cancerIn addition to the pretreatment level of sPD-L1 and exoPD-L1, dynamic changes in sPD-L1 and exoPD-L1 also need to be investigated to further understand the role of both forms of PD-L1; however, this was not investigated herein. Moreover, the tissue PD-L1 status of nine patients was not investigated mostly due to insufficient samples, which might have affected the results of the correlation between tissue PD-L1 and liquid PD-L1.In addition, as described in the “In this study, patients were divided into groups based on an arbitrary cut-off of exoPD-L1 and sPD-L1, and these were analyzed as categorical values, which showed statistical significance between sPD-L1 groups. However, when analyzed as continuous values, similar trends were shown, but statistically significant results were not obtained. The number of patients in this study (n = 99) may not have been sufficient to indicate statistical power as continuous values for sPD-L1 or exoPD-L1. Nevertheless, when sPD-L1 was analyzed in a multivariate model as a categorical value, its statistical significance remained along with the significance of other factors known to be associated with prognosis. Further research with more patients is needed to validate the clinical significance of extracellular PD-L1.The level of pretreatment sPD-L1 was associated with a more advanced disease in advanced GC and could be used as a prognostic marker for patients receiving systemic chemotherapy. Serum-derived exoPD-L1 may reflect the immunosuppressive state of patients with advanced GC. Further investigation is required to determine the prognostic and predictive role of both sPD-L1 and exoPD-L1 in patients receiving immune check point inhibitors.We prospectively enrolled patients with untreated GC at the Catholic University of Seoul St. Mary’s Hospital between March 2019 and March 2021. The eligibility criteria for the study were as follows: (1) ≥ 20 years old; (2) histologically confirmed gastric adenocarcinoma; (3) unresectable advanced or recurrent/metastatic disease; (4) scheduled to receive first-line systemic chemotherapy; (5) provision of written informed consent.The chemotherapy regimens used were fluorouracil and platinum doublet, 5-FU, oxaliplatin, and leucovorin (FOLFOX), capecitabine and oxaliplatin (XELOX), 5-FU and cisplatin (FP), S-1 and cisplatin (SP), and capecitabine and cisplatin (XP). Trastuzumab was added to the treatment regimen for human epidermal growth factor receptor 2 (HER2)-positive GC. Blood samples were collected before and after the chemotherapy.The study was approved by the Institutional Review Board of the Catholic University of Seoul Saint Mary’s Hospital (KC18TNSI0361). All patients signed a written informed consent before enrollment.The ExoQuick™ Exosome Precipitation Solution kit  was used to isolate serum-derived exosomes according to the manufacturer’s instructions. In brief, 500 µL of serum were added to 120 µL of exosome precipitation solution and slowly mixed and incubated for 1 h at 4℃ and centrifuged at 1,500 × g for 30 min. The supernatant was discarded and exosome pellet was precipitated at the bottom. The resulting pellet was resuspended into 250µL of sterile phosphate buffered saline (PBS) and stored at -80 °C until ready for use. Transmission Electron Microscopy (TEM) was used to confirm the isolated exosomes. For TEM, samples were freshly isolated and diluted in nuclease-free water. After fixation in 4% paraformaldehyde for 1 h, 5uL of exosome sample on grid were analyzed by TEM using a JEM 1010 transmission electron microscope  equipped with a Gatan Orius SC1000 CCD camera . The representative TEM image of the verified exosomes can be found in Supplementary Fig.  γ (IFN-γ), and PD-L1 were measured using ELISA kits , following the manufacturer’s instructions. For exoPD-L1 ELISA analysis, exosomes were isolated from 500 µL of serum and the exosome pellet was dissolved in 250 µL of PBS prior to use in experiments. The PD-L1 levels in extracted exosomes (exoPD-L1) were measured using the same method as described above. Information about antibodies used in ELISA is in Supplementary Table Plasma samples were centrifuged at 2,500 g for 10 min and the supernatants were stored at -80 ˚C until further usage. Plasma levels of Transforming growth factor β1 (TGF-β1), TGF-β2, Ki-67, granzyme B, Interleukin-10 (IL-10), Interferon-PD-L1 immunohistochemistry assays were performed using 22C3 pharmDx  on the Dako Autostainer Link 48 with EnVision DAB Detection System , according to the manufacturer’s instructions.The CPS was calculated by dividing the total number of PD-L1-positive cells  by the total number of tumor cells and multiplying the result by 100.Peripheral blood mononuclear cells (PBMCs) from patients were isolated from Ficoll-Paque density-centered blood that had been treated with EDTA and stored in liquid nitrogen before analysis. Markers used for thawing and staining PBMCs included CD4, CD8, CD69, CD45, CD3, and PD-1. The stained cells were acquired using BD Biosciences Canto II , and the data were analyzed using FlowJo software . Information about antibodies used in FACS is in Supplementary Table The time from the start of treatment to disease progression or death from any cause was defined as progression-free survival (PFS). The time from the start of treatment to death from any cause or the last follow-up date was defined as overall survival (OS). Treatment response was evaluated using the Response Evaluation Criteria in Solid Tumors version 1.1.Maximally selected rank statistics and a time-dependent receiver operating characteristic curve were used to determine the optimal cutoff value of exoPD-L1 and other clinical values, which were compared with the median value. The chi-squared and Fisher’s tests for categorical variables were used to compare the clinicopathological differences between the groups.p < 0.05. All statistical analyses were performed using R version 4.1.1 (http://www.r-project.org).Univariate analyses for OS and PFS were performed using the Kaplan–Meier method and the log-rank test. Cox proportional hazards regression analyses were used for multivariate models to verify the prognostic values of clinical variables, including exoPD-L1 and sPD-L1. Statistical significance was set at All procedures followed were in accordance with the ethical standards of the responsible committee on human experimentation  and with the Helsinki Declaration of 1964 and later versions. Informed consent to be included in the study, or the equivalent, was obtained from all patients.Supplementary Information.


Staphylococcus aureus outbreaks in the neonatal intensive care units (NICU) have been reported with the great majority due to methicillin-resistant Staphylococcus aureus. We describe successful control of an outbreak caused by methicillin-susceptible S. aureus (MSSA) in the NICU.spa typing.We report a MSSA bacteremia outbreak which occurred in the NICU at a tertiary level hospital from November 29, 2020 to January 6, 2021. Molecular typing of MSSA isolates were performed including multi-locus sequence typing (ST) and th case. Infection control measures, including isolation of cases, contact precaution and universal 0.5% chlorhexidine bathing of all NICU patients, were implemented. Surveillance cultures of patients (n=36) and health care workers (HCW) (n=60) were performed. Excluding bacteremia patients, 13% (4/31) of neonates and 32% (19/60) of HCW were identified as MSSA nasal carriers and targeted decolonization with intranasal mupirocin was performed. After implementation of control measures and decolonization, there were no new cases. Molecular analysis identified two strains [ST15 spa type t593 (n=3) and ST101 spa type t4171 (n=2)] as the cause of this bacteremia outbreak. Among MSSA nasal carriers, all 4 neonates colonized the ST15 spa t593 strain. ST15 spa t593 strain was also colonized in one HCW, however antibiotic susceptibility pattern differed. The rest of HCWs colonized many different types of MSSA. All MSSA isolates were negative for Panton-Valentine Leucocidin toxin gene.A total of 5 MSSA bacteremia cases occurred in 39 days. Outbreak investigation was initiated after the 5Molecular analysis identified two different MSSA strains in this outbreak. MSSA colonization was prevalent among HCWs, however molecular analysis showed variance in distribution. Although outbreak strains were not found in HCWs, one strain was colonized among other neonates, suggesting horizontal transmission and potential of further cases. The outbreak was successfully controlled with reinforcement of precautions, universal chlorhexidine bathing and surveillance cultures with targeted decolonization. Early recognition and prompt implementation of control measures are important for outbreak control in NICU.All Authors: No reported disclosures


This study investigates resistive switching behavior in a lateral 2D composite structure composed of bilayer graphene and 2D diamond (diamane) nanostructures formed using electron beam irradiation. The resulting bigraphene/diamane structure exhibits nonlinear charge carrier transport behavior and a significant increase in resistance. It is shown that the resistive switching of the nanostructure is well controlled using bias voltage. The impact of an electrical field on the bonding of diamane-stabilizing functional groups is investigated. By subjecting the lateral bigraphene/diamane/bigraphene nanostructure to a sufficiently strong electric field, the migration of hydrogen ions and/or oxygen-related groups located on one or both sides of the nanostructure can occur. This process leads to the disruption of sp Memristors as resistive switching memory devices play a critical role in the energy-efficient implementation of artificial intelligence. Memristors possess unique properties that stem from their ability to operate at atomic scales, allowing, for example, the formation or rupture of metallic filaments using voltage signals to encode synaptic weights ,2. The hTwo-dimensional materials represent a novel class of nanostructured materials that hold great promise as emerging materials for ultra-thin semiconductor devices in the future . This fa2 substrates, conductive graphene filaments within a graphene oxide matrix mainly govern the switching behavior. By manipulating the sp2/sp3 domains using oxidation/reduction processes, the desired graphene/graphene oxide-based memories can be achieved.Graphene-based layer heterostructures, renowned for their remarkable electrical, thermal, and mechanical properties, exhibit immense potential for memristor applications. Recent studies have showcased the promise of graphene/graphene oxide heterostructures in resistive memories ,10. In v3-hybridized bonds. This chemically induced phase transition facilitates the controlled formation of high-resistivity diamane islands within the bilayer graphene structure by selectively attaching reference atoms. This controlled formation process allows for the precise engineering of the electrical properties of the composite system.Ultra-thin diamond film, also known as diamane , emerges3Ga5SiO14 surface has been successfully demonstrated. In the investigation, two layers of graphene were transferred onto a langasite substrate and subjected to focused electron beam irradiation through a layer of polymethyl methacrylate. The results of these studies revealed the local diamondization of bilayer graphene during the irradiation process. The observed results can be explained using the framework of the theory of a chemically induced phase transition, which is associated with the formation of sp3 bonds between carbon atoms and hydrogen and oxygen atoms released from PMMA and langasite, respectively, upon irradiation of the structure with an electron beam. Theoretical calculations and experimental evaluations of the sp3-hybridized carbons in the modified bilayer graphene structure on langasite provide evidence for the formation of diamane in the irradiated regions. These findings contribute to our understanding of the mechanisms underlying the transformation of bilayer graphene into diamane and pave the way for further exploration of the properties and potential applications of this novel material.In recent research , the forThe focus of this study is on the resistive switching phenomenon in this lateral two-dimensional composite structure. The first part of this paper delves into an examination of the current–voltage characteristics of bilayer graphene, revealing differences in behavior between the initial and electron beam-irradiated structures. The second part of this study involves the analysis of the structural features of the formed nanomaterial. This analysis was conducted through the mapping of the intensity ratio between the D and G Raman bands. The final part of the work is dedicated to the study of the resistive switching effect in the formed bilayer graphene/diamane/bilayer graphene structure in an external electric field and the theoretical investigation of the response of the structure to the electric field.2 foil with a purity of 99.999% from Alfa Aesar, was loaded into the CVD reactor and evacuated to a base vacuum pressure of less than 10−4 Torr.Graphene monolayers were synthesized using chemical vapor deposition (CVD) on a copper catalyst foil. The CVD process was carried out in a horizontal quartz tube measuring 2400 mm in length and 152 mm in diameter, which was placed inside a six-zone furnace with a length of 1500 mm. A 25 μm thick copper foil, specifically a 10 × 30 cm4) and hydrogen (H2), along with argon (Ar) as the carrier gas, was introduced into the reaction chamber at a pressure of 600 mTorr. The flow rates of the gases were set at 40 cm3/min for the CH4, 100 cm3/min for the H2, and 2000 cm3/min for the Ar. The growth process was carried out for 30 min, after which the reaction chamber was cooled down to room temperature at an average rate of 14 °C/min, maintaining the same flow rates of Ar and H2, but without the presence of methane.To initiate the growth of graphene layers, the temperature inside the chamber was raised to 1020 °C. A mixture of methane (CH3Ga5SiO14 (LGS) substrate. The transfer was facilitated by using a poly(methyl methacrylate) (PMMA) layer as support. The PMMA layer was spin-coated onto the graphene-covered copper foil and dried in an oven at 120 °C for 10 min. Subsequently, the PMMA/graphene layer was immersed in a solution of distilled water to facilitate the separation of the graphene layer from the copper foil. The PMMA was then removed by soaking the sample in acetone or isopropyl alcohol, and the resulting single-layer graphene (SLG) on the LGS substrate was rinsed with a 30% hydrochloric acid (HCl) solution at 60 °C for 30 min to eliminate any residual Fe3+ ions. This process ensured the preparation of a high-quality graphene layer with a low defect density on the LGS substrate.To transfer the grown graphene monolayers, a common two-step process was employed  . A 100× objective  was used, along with a 532 nm (or 488 nm) laser with a power of 1 mW . A GX polarized filter-AN360 (Olympus) was also employed. Each spectrum was obtained by taking 10 measurements within a 10 s accumulation time. Multiple analyses, ranging from 3 to 6, were performed at different locations for each sample.® SMU Instrument .To prepare the samples for further analysis, a layer of PMMA-950 resist with a thickness of 300 nm was deposited onto the system. These samples were irradiated using an EVO-50 scanning electron microscope equipped with a Nanomaker electron beam control. The Raman spectra of nanostructures obtained using irradiation with a focused electron beam were measured using a Bruker Senterra micro-Raman system. The excitation wavelength for the Raman measurements was 532 nm, and the laser power at the sample point was set to 10 mW. Each point on the map was captured for 2 × 20 s. Transport measurements of the nanostructures were conducted using a microprobe station EPS150TRIAX  and a Keithley 2636B System SourceMeterThe effect of a lateral electric field on the atomic structure of graphene/diamane/graphene was investigated using density functional theory (DFT) ,21. The 3Ga5SiO14 substrate under focused electron beam irradiation was reported [3-hybridized carbon confirmed the formation of diamane nanoclusters in the irradiated regions of bilayer graphene.Recently, the formation of diamane nanostructures in bilayer graphene on a Lareported . The obsreported . This trreported . The mod3Ga5SiO14 substrate with Al/Cr side electrodes, both before (a) and after (b) the electron beam-induced transition from bilayer graphene to diamane. The insets in 3Ga5SiO14 substrate with two Al/Cr electrodes (a), and the irradiated structure with an electron beam passing through PMMA along a specific line to locally convert bilayer graphene to diamane (b). Initially, the bilayer graphene on a La3Ga5SiO14 substrate with Al/Cr side electrodes exhibits a linear current–voltage characteristic and a resistance of 360 Ohms . Previous research has shown that electron beam irradiation of GO effectively reduces it, leading to a decrease in the density of sp3-hybridized carbon and a relative decrease in the intensity of the D peak without any shift. In the case of a similar bilayer graphene structure, irradiation with an electron beam resulted in a shift of the D peak to 1335 cm−1 and an increase in intensity [−1, indicative of diamond-like hybridization [−1 [3-hybridized carbon increases, and the characteristic peak shifts toward the Raman mode associated with diamane. The Raman spectra obtained from non-irradiated and irradiated areas of bilayer graphene are shown in In ntensity . Additiodization , was obstion [−1 . Consequ3 carbon in bigraphene irradiated with a locally focused electron beam can be obtained from the approach in [AC = 4.2, SC = 0, Ar = 3 nm, and Sr = 1 nm, and for the D’ peak, AC = 0.5, SC = 0.33, Ar = 2.6 nm, and Sr = 1.4 nm [The content of sproach in ,33 usingposed in . For the= 1.4 nm .3 carbon can be estimated using the intensity ratio I(D)/I(G), as depicted in 3 carbon in the irradiated region amounts to 1012 cm–2 . Additionally, The voltage sweeps from 0 V to −1 V and then to 1 V and back to 0 V resulting in resistive switching at −0.9 and 0.9 V from a high-resistance state (~20 kOm) to a low-resistance state (~0.5 kOm) and back, respectively, demonstrating an on/off ratio of ~40, which is comparable to previously reported characteristics of memristors and photomemristors based on 2D materials ,12,34. I3 carbon bonds and subsequently transform the structure into bigraphene. This alteration in the carbon bonding configuration can have significant implications for the electronic and structural properties of the nanostructure.When graphene layers are exposed to the adsorption of atoms or molecular groups, they can bind together and undergo a chemically induced phase transition, resulting in the formation of a diamond film. It is important to note that this phase transition occurs when the adsorbing atoms or molecular groups have a radius comparable to that of a carbon atom. If the adsorbing species are too large, the steric factor hinders the complete coverage of the film surface. In this context, oxygen-containing groups of moderate size are particularly suitable for providing full passivation of the diamane film. These groups can effectively bind to the surface of the film, ensuring its stability and preventing the formation of defects. Furthermore, when a sufficiently strong electric field is applied to a lateral bigraphene/diamane/bigraphene nanostructure, it can induce the migration of hydrogen ions (and/or oxygen-related groups) that are located on one or both sides of the nanostructure. This migration process can break the sp3Ga5SiO14 surface was demonstrated, we designed a corresponding model of a diamane film arranged on a substrate functionalized with hydrogen atoms from the outer side. During the relaxation process, the surface oxygen atoms of langasite shifted and formed connections with the carbon atoms at the interface, thereby stabilizing the geometry of the diamane film. The resulting structure exhibited a hexagonal diamane film with the In the previous work , in whic3Ga5SiO14 substrate and retained only oxygen atoms in the form of peroxide groups on one side, while hydrogen atoms released from the PMMA coating were present on the other side. This simplified model consisted of a bilayer graphene/diamond heterostructure that was periodic only along the x-axis, forming a ribbon-like structure, as depicted in In this study, we specifically examined the response of the 2D diamond structure to an external electric field. To simplify the model, we removed the LaE0) and the structure with one (E1) or two (E2) detached oxygen molecules.The stability of the diamond film is closely related to the strength of the C-O and C-H bonds. Functional groups on the film surface contribute to its stability, and their desorption leads to the cleavage of the film. We defined the cleavage barrier of the diamond cluster as the energy difference between the original structure (2 to 2.38 eV/O2). However, the response to an electric field remains the same for ribbons of different widths, allowing us to focus on studying the minimal structure.Our findings indicate that a diamond-like nanoribbon with a minimum width of 1 nm (consisting of four atomic layers arranged perpendicular to the surface) is thermodynamically stable. Narrower ribbons are unstable and delaminate into bilayer graphene. As the ribbon width increases, the energy barrier for diamond cluster cleavage also increases . The local diamondization of bilayer graphene on a La2 carbon bonds in the bilayer graphene.Furthermore, the resistive switching behavior of a nanostructure consisting of bilayer graphene, diamane, and bilayer graphene was investigated. A voltage sweep from 0 V to −1 V and then to 1 V and back to 0 V resulted in a switch from a high-resistance state to a low-resistance state and back. This resistive switching behavior was attributed to the migration of oxygen-related groups, leading to the restoration of sp3 carbon bonds and the disruption of the diamane structure. The alteration in the carbon bonding configuration and the disruption of the diamane structure play a crucial role in this process, enabling the system to exhibit distinct electrical properties and undergo reversible transitions between high and low resistance states.In our theoretical investigation, we focused on understanding the influence of an electric field on the bonding of functional groups to the surface and the overall stability of a diamond film. To achieve this, we designed a graphene/diamane heterostructure, in which the diamond layer is stabilized by oxygen atoms in the form of peroxide groups from the langasite substrate on one side and hydrogen atoms released from the PMMA coating on the other side. This model represents a diamond nanoribbon embedded within a graphene bilayer. The stability of the diamond film is closely tied to the strength of the C-O and C-H bonds. The presence of functional groups on the film surface contributes to its stability, and their desorption can lead to the cleavage of the film. Our simulations demonstrate that when a sufficiently strong electric field is applied to a lateral bigraphene/diamane/bigraphene nanostructure, it can induce the migration of oxygen-related groups. This migration process results in the breaking of interlayer spThe results of this study highlight the potential of using bilayer graphene/diamane structures for resistive switching applications. The electron beam-assisted chemically induced phase transition of bilayer graphene to diamane provides a new technology for the direct ‘’writing’’ of memristor devices on bilayer graphene using electron beam lithography. It opens new possibilities for using large-scale bilayer graphene substrates for 2D layered memristor fabrication using CMOS-compatible technology. The ability to control the conductive properties of the formed structure using local phase transitions through bias voltage opens up possibilities for the development of novel memristor devices with improved performance. Further research can optimize of the fabrication process to integrate these memristor structures into CMOS devices for various applications, including the power-efficient implementation of artificial intelligence and advanced computing systems.