A microflow cytometer chip driven by the absorbent force of on-chip superabsorbent materials

The objective of our study was to develop an absorbent-force-driven microflow cytometer chip (AMCC) that used superabsorbent materials as the fluid-driving source to allow chip operation without external power and easy miniaturization. In our study, the fluid flow characteristics inside the AMCC, and the impact of the microstructure size on the flow velocity and hydrodynamic focusing width of AMCC were investigated. Results showed that superabsorbent materials allowed stable microchannel flow and hydrodynamic focusing and that the flow rate and hydrodynamic focusing width of the AMCC could be controlled by varying the microchannel dimensions (the mean flow velocity was approximately 1.6 mm/s to 18.5 mm/s, and the hydrodynamic focusing width was approximately 3 μm to 20 μm). In addition, the fluorescent test results of AMCC were noted to be consistent with those of a large-scale flow cytometer (BD, FACSCalibur), thereby confirming the feasibility of using superabsorbent materials as the fluid-driving source in microfluidic chips. AMCC can effectively reduce the amount of test solution used, has the advantage of easy miniaturization, and provides a low-cost fluid actuation method that can be conveniently obtained, fabricated, and miniaturized.