Design and fabrication of an on-chip micro flow cytometer with integrated micro-lens

In this paper, the design and fabrication of an on-chip micro flow cytometer chip with integrated micro-lens with a size of 1500 mm × 1000 mm × 2 mm is put forward, and the chip mainly consists of the unit of three-dimensional micro fluidic channel used for hydraulic focusing and the unit of micro-lens used for optical detection. In specific, firstly, the technology of the tilted ultra-violet (UV) lithography and the secondary overlay UV lithography of SU-8 resist are used to build a mould. Then, soft photolithography of polydimethylsiloxane (PDMS) is utilized to make a PDMS double casting to get a chip structure consistent with the original mould. Finally, after bonding, this PDMS chip, being injected with fluid with a certain pressure, can be changed into the micro flow cytometer with integrated micro-lens in situ on the same chip. The experiment shows that because the shape of the micro-lens in the chip can be changed with the change of the pressure and the amount of the liquid injected, the chip can meet the practical needs. Moreover, this kind of chips shares the merits of small size, simple fabrication process, low cost, and mass production as well.