Microcapillary-assisted acoustoelectric platform for selective single-cell isolation and in situ transfection

Abstract Single-cell transfection technologies hold tremendous promise for precision cell and immunotherapies. However, monolithic integration of cell isolation with targeted intracellular delivery remains technically challenging, especially within complex biological matrices. Herein, we present a microcapillary-assisted acoustoelectric single-cell selective isolation and sonoporative transfection platform (μC-ASSIST), which seamlessly sequences microcapillary-assisted dielectrophoresis (μC-DEP) for deterministic single-cell trapping with high-frequency surface acoustic waves (SAWs) for transient membrane poration within a unified workflow. We demonstrate the label-free, high-efficiency extraction of human non-small cell lung cancer (A549) cells from a complex white blood cell (WBC) background with a capture efficiency of 95%. Furthermore, we validate the highly efficient, contact-free intracellular delivery of diverse cargoes ranging from small dyes (PI) to functional small interfering RNA (siRNA) and large plasmid DNA (mRFP-C3), maintaining a high cell viability of 83.7% alongside a 78.1% transfection efficiency. Crucially, the targeted delivery of siBcl-xL significantly suppressed target mRNA expression and profoundly inhibited tumor cell motility. By circumventing off-target effects and cumbersome manual handling, the μC-ASSIST platform establishes a highly versatile, streamlined paradigm for precision single-cell engineering, holding immense potential for advancing functional genomics and next-generation gene therapies.