Accelerated Droplet Routing on MEDA Biochips Considering Shape-Dependent Velocity Models Through Guidance and Lower-Bound Constraints

Digital microfluidic biochips are widely used for automated biochemical and diagnostic applications such as molecular analysis, immunoassays, and point-of-care testing. Among them, micro-electrode-dot-array (MEDA) biochips enable fine-grained droplet manipulation with shape-dependent velocity, which significantly increases routing flexibility but also computational complexity. This work proposes an efficient droplet routing method for MEDA biochips that reduces computational time while maintaining or improving solution quality. The proposed method introduces a guidance constraint that consistently directs droplets toward the target cell and integrates a solver-friendly model with a tight lower-bound design. Experimental results demonstrate that, for instances solvable by the existing method, the proposed method achieves comparable or better Routing time while reducing Solution-finding time by 72.3%. Moreover, the Solution-finding rate improves from 33.3% to 85.3% over all problem instances. Notably, for instances that cannot be solved within the time limit by the existing method, the proposed method successfully finds optimal solutions in 72.7% of the cases. These results indicate that the proposed method enables faster solution discovery, and extends solvability to previously intractable routing problems.