An inertial-acoustofluidic platform for bioanalysis: concurrent, high-precision, high-throughput separation of cells and bacteria.

Efficient separation of cancer cells from whole blood is vital for early cancer diagnosis. However, disease progression often causes complications that reduce survival, such as cholangitis in liver cancer due to bile-duct compression, with Escherichia coli (E. coli) and Klebsiella as common pathogens. To address this, we developed a sheathless microfluidic sorter that integrates inertial focusing with surface acoustic wave (SAW) manipulation to simultaneously isolate cancer cells and bacteria. Specifically, we introduce a label-free, SAW-driven microfluidic platform that couples passive inertial focusing with active SAW manipulation to enable concurrent separation of cancer cells and bacteria; Cr/Au interdigital transducers (IDTs) are patterned on a 128° Y-cut LiNbO₃ substrate. The system first employs a contraction-expansion microchannel to achieve preliminary separation. Larger particles are then deflected by a slanted interdigital transducer (S-IDT), improving bacterial sorting purity. Small particles are enriched at the first outlet (purity > 96%), and the remaining targets are further refined by a focusing interdigital transducer (F-IDT). Tests with polystyrene (PS) particles achieved >96% purity, and in clinical samples, sorting efficiency and purity exceeded 93% for HepG2 cells and E. coli, with HepG2 viability above 94%. This compact platform unifies active and passive mechanisms, offering promise for early diagnosis and real-time monitoring of complications.