Cargo Delivery to Cells Using Laser-Irradiated Carbon-Black-Loaded Polydimethylsiloxane

Effective intracellular delivery is essential for successful gene editing of cells. Spatially selective delivery to cells that is simultaneously precise, consistent, and nondestructive remains challenging using conventional state-of-the-art techniques. Here, we introduce a carrier-free method for spatiotemporal delivery of fluorescently labeled cargo into both adherent and suspension cells using carbon-black-embedded polydimethylsiloxane (PDMS) substrates irradiated by nanosecond laser pulses. This low-cost, biocompatible material, coupled with an optical approach, enables scalable, spatially selective, and sequential delivery of multiple cargo molecules, including FITC-Dextran and siRNA, to a broad range of cells. Notably, we achieved siRNA delivery into the cytoplasm of hard-to-transfect K562 cells with 45% efficiency, while maintaining nearly 100% cell viability.