PathDriver-Wash: A Path-Driven Wash Optimization Method for Continuous-Flow Lab-on-a-Chip Systems

Rapid advances in microfluidics technologies have facilitated the emergence of highly integrated lab-on-a-chip (LoC) biochip systems. With such coin-sized biochips, complicated bioassay procedures can be executed efficiently without any human intervention. To ensure the correctness and precision of assay outcomes, however, cross-contamination among different fluid samples/reagents needs to be dealt with separately during assay execution. As a consequence, wash operations have to be introduced and a wash path network needs to be established on the chip to remove the residues left in flow channels. To realize optimized assay procedures with efficient wash operations, we propose PathDriver-Wash in this paper, a path-driven wash optimization method for continuous-flow LoC biochip systems. The proposed method includes the following three key techniques: 1) The necessity of contamination removals is analyzed systemically to avoid unnecessary wash operations, 2) wash operations are integrated with the regular removal of excess fluids, so that extra path occupations caused by wash can be minimized, and 3) optimized wash paths and time windows are computed and assigned to wash operations, so that the completion time of assays can be minimized. Experimental results demonstrate that the proposed method leads to highly efficient wash procedures as well as minimized assay completion times.