Parametric Analysis of SAW-Driven Droplet Streaming for Biomedical Lab-on-Chip Systems

Abstract

Surface acoustic wave (SAW)–induced acoustic streaming has emerged as a powerful mechanism for manipulating microscale fluids in droplet-based microfluidic systems, with promising applications in biomedical diagnostics and bioelectronic lab-on-chip platforms. This study presents a numerical investigation of acoustic streaming in sessile droplets driven by SAWs, with a focus on understanding the influence of key physical parameters on flow behavior and mixing performance. A three-dimensional multiphysics model was developed to simulate the coupling between surface acoustic wave excitation, acoustic pressure fields, and induced fluid flow within a droplet. Parametric analyses were conducted by varying the SAW excitation frequency and droplet size to evaluate their effects on streaming velocity and mixing efficiency. The results reveal that both parameters significantly affect the formation of vortex structures and the intensity of internal recirculation within the droplet. Lower excitation frequencies generally lead to stronger acoustic streaming, while droplet size influences the spatial distribution of flow patterns. These findings provide insights into the design and optimization of SAW-driven microfluidic platforms for efficient biological sample manipulation and rapid mixing in biomedical sensing and diagnostic applications.