An all-glass microfluidic flow cytometer

The majority of current microfluidic flow cytometers were fabricated by a tractable material, PDMS (Polydimethylsiloxane), which exhibited unsatisfactory optical performances. In this work, we firstly presented an all-glass microfluidic flow cytometer (agFCM) which remarkably improved the optical performance and corresponding blood cell detection accuracy.Picosecond laser was introduced to pattern microfluidic channels, on-chip optical waveguides and on-chip micro-lens on a glass substrate (made with fused silica). The glass debris and burrs caused by laser machining were removed from microfluidic channels by ultrasonic cleaning and CO2 laser reflux respectively. The fabricated glass micro-channel with on-chip lens was sealed by bonding another glass layer to form the agFCM chip. The experimental results demonstrated that, compared with PDMS based devices, agFCM chip improved the optical performances as follows: 1) Scattering haze of material surface was reduced from 50% to 1.4%, effective light transmittance has increased5%.2) the focused excitation spot in detecting area was reduced from 3.60 to 2.64μm. 3) The coupled optical loss of the chip waveguide is reduced to less than 1dB.To sum up, introducing glass as chip material improved the signal to noise ratio by 0.66dB.The performances of agFCM were verified by microsphere experiments. As expected, the improved optical parameters of agFCM resulted in related improvement on detecting accuracy.