saw-based isolation of label-free and label-based rare cells: a review of experimental investigations

Biological and biomedical microfluidic devices have been widely used to isolate rare cells. although various techniques are available for analyzing rare cells, many are limited by high sample loss and low selectivity. surface acoustic wave (saw) technology offers a promising active approach for cellular analysis due to its simplicity, low cost, and compatibility with other microfluidic devices, making saw-based microchips essential tools for manipulating rare cells. this review outlines the principles of acoustic isolation, introduces theoretical concepts and key equations, and examines recent experimental studies in this field. findings indicate that saw-based microfluidic devices have been effectively employed for manipulating, isolating, focusing, and patterning rare cells, achieving a cell separation efficiency of approximately 80-90%, though slightly lower than that for microparticles. this paper also discusses existing challenges and research gaps, recommending future directions such as the development of novel three-dimensional designs, optimization of acoustic devices through artificial intelligence, and the integration of acoustic methods with other techniques.