Ultra-Low Intensity Light Pulses for Large Cargo Delivery into Hard-to-Transfect Cells using rGO Mixed PDMS Microtip Device

Nanoparticles-mediated photoporation has arisen as universal intracellular delivery tool; however, the direct interaction of nanoparticles and cells hampers its clinical translation. Here, we report a uniform contactless intracellular delivery that transfect large number of cells within a minute and avoids the direct contact of nanoparticles and cells, thereby improving the cell viability. Our platform consists of an array of polydimethylsiloxane (PDMS) mixed reduced graphene oxide nanoflakes (rGO) pyramidal microtips, which uniformly distributed at the apex of the tip. The extraordinary optoelectronic properties of rGO were combined with the micro-pyramidal cavity to entrap light in micro-cavity and efficiently convert into heat through multiple reflections and absorptions. As a result, an ultralow infra-red laser pulse irradiation, could create cavitation bubbles followed by cell membrane deformation and biomolecular delivery. Using this delivery platform, we have achieved the delivery of small to large cargo (668 Da to 465 kDa) in various mammalian cells, including hard-to-transfect H9C2 cardiomyocytes. The best results were achieved for enzyme (465 kDa) delivery with a transfection efficiency and cell viability of 95% and 98%, respectively, in SiHa cells. The highly efficient cargo delivery tool demonstrated a safe and effective approach for cell therapy and diagnostics.