Fabrication and Performance of a Photonic-Microfluidic Integrated Device

Fabrication and performance of a functional photonic-microfluidic flow cytometer is demonstrated. The devices are fabricated on a Pyrex substrate by photolithographically patterning the microchannels and optics in a SU-8 layer that is sealed via a poly(dimethylsiloxane) (PDMS) layer through a unique chemical bonding method. The resulting devices eliminate the free-space excitation optics through integration of microlenses onto the chip to mimic conventional cytometry excitation. Devices with beam waists of 6 mu m and 12 mu m in fluorescent detection and counting tests using 2.5 and 6 mu m beads-show CVs of 9%-13% and 23% for the two devices, respectively. These results are within the expectations for a conventional cytometer (5%-15%) and demonstrate the ability to integrate the photonic components for excitation onto the chip and the ability to maintain the level of reliable detection.