Control of the Speed of a Light-Induced Spin Transition through Mesoscale Core-Shell Architecture.
The rate of the light-induced spin transition in a coordination polymer network solid dramatically increases when included as the core in mesoscale core-shell particles. A series of photomagnetic coordination polymer core-shell heterostructures, based on the light-switchable Rb aCo b[Fe(CN)6] c· mH2O (RbCoFe-PBA) as core with the isostructural K jNi k[Cr(CN)6] l· nH2O (KNiCr-PBA) as shell, are studied using temperature-dependent powder X-ray diffraction and SQUID magnetometry. The core RbCoFe-PBA exhibits a charge transfer-induced spin transition (CTIST), which can be thermally and optically induced. When coupled to the shell, the rate of the optically induced transition from low spin to high spin increases. Isothermal relaxation from the optically induced high spin state of the core back to the low spin state and activation energies associated with the transition between these states were measured. The presence of a shell decreases the activation energy, which is associated with the elastic properties of the core. Numerical simulations using an electro-elastic model for the spin transition in core-shell particles supports the findings, demonstrating how coupling of the core to the shell changes the elastic properties of the system. The ability to tune the rate of optically induced magnetic and structural phase transitions through control of mesoscale architecture presents a new approach to the development of photoswitchable materials with tailored properties.
Core-Shell Heterostructured CuFe@FeFe Prussian Blue Analogue Coupling with Silver Nanoclusters via a One-Step Bioinspired Approach: Efficiently Nonlabeled Aptasensor for Detection of Bleomycin in Various Aqueous Environments.
We synthesized novel core-shell heterostructured Prussian blue analogue (PBA) nanospheres coupled with silver nanoclusters (AgNCs) via a one-step bioinspired approach and further exploited these as aptasensors for the detection of a trace antibiotic, bleomycin (BLM). Using FeFe Prussian blue (FeFe PB) as the core, a bimetallic CuFe@FeFe PBA layer was prepared by coupling with AgNCs synthesized by taking the BLM-targeted aptamer as a template (denoted by AgNCs/Apt@CuFe@FeFe). The coupling of AgNCs/Apt via a one-step bioinspired approach not only can improve the sensing performance of CuFe@FeFe-based aptasensors but also can shorten the aptasensor fabrication procedure. Due to the strong coordination interaction between abundant Fe(II) ions contained in CuFe@FeFe PBA nanospheres and BLM (represented by Fe(II)·BLM), the Fe(II)·BLM complex formed enables aptamer strands to undergo an irreversible cleavage event that can result in a significant change in electrochemical activity. Electrochemical results displayed that both CuFe@FeFe- and AgNCs/Apt@CuFe@FeFe-based aptasensors exhibited high sensitivity and selectivity, good stability and reproducibility, and acceptable applicability toward BLM. In comparison with the pristine CuFe@FeFe-based aptasensor (limit of detection (LOD) = 0.49 fg mL-1 within the BLM concentration from 1.0 to 2.0 ng mL-1), the as-prepared AgNCs/Apt@CuFe@FeFe-based aptasensor gave a extremely lower LOD value of 0.0082 fg mL-1 within a relatively narrow BLM concentration range (0.01 fg mL-1 to 0.1 pg mL-1). The proposed method can broaden the application of PBA nanomaterials in food safety and biosensing fields and provides a potential determination method for rapidly detecting BLM in various aqueous environments.
Analysis of Macro and Micronutrients in Soils from Palestine Using Ion Exchange Membrane Technology
Ion Exchange membrane technology (IEM) is a method that allowed a single extraction process and a single subsequent measurement of different elements that are available in soil. The values of the available forms of the different macro- and micronutrients obtained by IEM extraction were compared with the values of the soluble form obtained by conventional extraction methods. In surface soil sample, the concentrations of available potassium, nitrate, phosphate, iron and boron were 37.7 mg kg–1, 17.5 mg kg–1, 3.6 mg kg–1, 171.0 μg kg–1, and 4.2 μg kg–1 respectively were greater than that of soluble forms of the same elements which were 7.0 mg kg–1, 9.2 mg kg–1, 0.4 mg kg–1, 109.0 μg kg–1, and 1.9 μg kg–1 respectively.