Hydrodynamic Cell Capture and Release Microfluidic Chip for Cancer Drug Screening

In forward capture mode, the main channel exhibits the lowest flow resistance, and cells flow along the main channel and are captured in the traps. In reverse release mode, the main channel switches to the highest flow resistance, and cells in the traps are efficiently released backward along bypass channels to the collection outlet without recapture. Using K562 cells, the effects of channel width on cell capture and release efficiencies were investigated to determine the optimal design parameters.

Finally, the device achieved a capture efficiency of 92.0 ± 4.4% and a release efficiency of 70.0 ± 8.6%, with maximum values of 97.2% and 87.8%, respectively. To further verify the device’s applicability for drug screening, four concentrations of nilotinib were generated using the device. After K562 cells were cultured under the four concentrations for 48 h, the on-chip IC₅₀ of nilotinib against K562 cells was determined to be approximately 10.79 μM, close to the result of 14.10 μM measured in the off-chip microplate.

Subsequently, the treated cells were collected after reverse release and subjected to RNA-seq. The results showed that 20 μM nilotinib treatment significantly downregulated the expression of <i>MYC</i>, <i>LYN</i>, and <i>BCL2L12</i>, which are related to BCR-ABL signaling, by 18.3-fold, 3.6-fold, and 4.7-fold, respectively. Meanwhile, the treatment inhibited the viability of K562 cells to 23.9 ± 3.5%.