Light activated nanocomposite thin sheet for high throughput contactless biomolecular delivery into hard-to-transfect cells

High throughput intracellular delivery of biological macromolecules is crucial for cell engineering, gene expression, therapeutics, diagnostics, and clinical studies, but most existing techniques are either contact-based or has throughput limitations. Here, we report a light-activated, contactless, high throughput photoporation method for highly efficient and viable cell transfection of more than a million of cells within a minute. We fabricated reduced graphene oxide(rGO) nanoflakes mixed with polydimethylsiloxane (PDMS) nanocomposite thin sheet with an area of 3 cm2 and a thickness of ~600 µm. Upon infrared (980 nm) nanosecond pulse laser exposure, the rGO nanoflakes induced heat and created photothermal bubbles leading to cell membrane deformation and biomolecular delivery. Using this platform, we achieved delivery of small to large size cargo such as propidium iodide (PI) dye (668 Da), dextran (3000 Da), siRNA (20–24 bp), EGFP (6159 bp) and enzyme (465 kDa) in L929, N2a, Hela cells as well as hard-to-transfect NiH3T3 and HuH7 cells. The best results achieved for enzymes were ~97% transfection efficiency and 98% cell viability in Huh7 cells. This highly efficient cargo delivery tool is simple, easy to use, and the dimensions can be varied in accordance with user requirements. This safe and successful method may find applicability in diagnostics and cell therapy.