Surface acoustic wave microfluidics: device innovations and the triangle balance in micro /nanoscale manipulation
This paper aims to address the critical transition of surface acoustic wave (SAW) microfluidics from microscale to nanoscale precision manipulation by deriving a systematic framework from a critical review of device performance data to analyze the inherent engineering constraints among resolution, throughput and biocompatibility, where resolution and throughput form the primary conflicting objectives, and biocompatibility serves as the power-density-defined feasibility boundary. The review introduces a “Resolution-Throughput-Biocompatibility” triangular analysis framework. Guided by this framework, it methodically examines the working mechanisms and performance limitations of various SAW devices developed over the past fifteen years, considering two key dimensions: acoustic field modes and device configurations. The analysis reveals that different device architectures occupy distinct positions within the triangular framework, each emphasizing specific trade-offs. The findings highlight the need for future integration of multi-physical field synergy, intelligent algorithmic control, and modular manufacturing processes to overcome bottlenecks in nanoscale manipulation, throughput and system stability. This paper provides a novel triangular framework that systematically compares SAW device designs, offering a comprehensive perspective on the trade-offs between resolution, throughput and biocompatibility. It also outlines future directions integrating advanced control and manufacturing strategies, paving the way for practical applications in point-of-care diagnostics and online industrial monitoring.