Optofluidic Device Based Microflow Cytometers for Particle/Cell Detection: A Review <s> Device Integration <s> An optimal excitation beam shape is necessary to perform reliable flow cytometric analysis but has so far not been implemented in a photonic-microfluidic integrated (i.e. optofluidic) device. We have achieved this feature by integrating a 1D lens system with planar waveguides and microfluidic channel on a substrate using one patterning material via a one-shot process. In this paper, we report the method of design and the performance of specifically formed excitation regions shaped to be ideal for reducing double detections, improving SNR, and for reliable detection in a flow cytometry application. Demonstration of different sizes via changes to lens design shows the ability to control the width of the shaped beam according to a targeted detection. <s> BIB001 </s> Optofluidic Device Based Microflow Cytometers for Particle/Cell Detection: A Review <s> Device Integration <s> Polydimethylsiloxane (PDMS) and SU-8 are currently two very commonly used polymeric materials in the microfluidics field for biological applications. However; there is a pressing need to find a simple, reliable, irreversible bonding method between these two materials for their combined use in innovative integrated microsystems. In this paper, we attempt to investigate the aminosilane-mediated irreversible bonding method for PDMS and SU-8 with X-Ray Photoelectron Spectroscopy (XPS) surface analysis and bonding strength tests. Additionally, the selected bonding method was applied in fabricating a microelectrode array (MEA) device, including microfluidic features, which allows electrophysiological observations on compartmentalized neuronal cultures. As there is a growing trend towards microfluidic devices for neuroscience research, this type of integrated microdevice, which can observe functional alterations on compartmentalized neuronal culture, can potentially be used for neurodegenerative disease research and pharmaceutical development. <s> BIB002
A multilayered PDMS/SU-8 devices is commonly used in an optofluidic microflow cytometer. Standard techniques, like wet and dry etching on glass or silicon substrates, have been replaced by soft lithography, photolithography and different bonding techniques in recent decades. Figure 10 shows the individual layers for the integration of the device, and the detailed process can be seen in Figure 11 . The PDMS layer is fabricated by PDMS molding and functioned as a upper layer to seal the fluidics and to form an upper optical cladding layer. The SU-8 layer is patterned on a silicon or glass substrate by exposure to UV light through photomasks. Due to the high aspect ratio, the waveguides and optical components can be integrated on the SU-8 layer. To assemble the device, the PDMS layer is bonded to the SU-8 layer after a plasma treatment BIB001 BIB002 . The PDMS cover provides a complete seal, and extra glass pads are bonded on the top surface of PDMS. The sandwiched device is rigid enough and can withstand a high pressure. Custom optical and fluidic components can be integrated on a small chip to achieve specialized and efficient function. 