Improving the cell viability and isolating precision of laser induced forward transfer process by maintaining a proper environment with a micro-chip.

Background: Aiming to improve the laser-induced forward transfer (LIFT) cell isolation process, a polydimethylsiloxane (PDMS) layer with micro-hole arrays was employed to improve the cell separation precision, and a microchip with heater was developed to maintain the working area at 100% humidity and 37 degrees C with the purpose to preserve the viability of the isolated cells. Methods: A series of experiments were conducted to verify the contributions of the optimization to LIFT cell isolation process as well as to study the effect of laser pulse energy, laser spot size and the titanium thickness on cell isolation. With 40 mu m laser spot size and 40 nm thick of titanium, laser energy threshold for 100% single cell isolating succeed ratio is 7 mu J. Results: According to the staining images and proliferation ratios, the chip did help to improve the cell availability and the cells can recover from the juries at least a day earlier comparing to the samples processed without the chip. Conclusion: With a Lattice Boltzmann model, the cell isolation process is numerically studied and it turns out that the micro-hole makes the isolation process shift to a micro-syringe injection model leading to the lower laser energy threshold for cell separation and fewer injuries.