One major barrier to advancing fundamental studies of biological cargoes for clinical use has been effective delivery into the cytoplasm. Available methods such as electroporation, viral techniques, and liposomal reagents come with respective strengths and weaknesses depending on the application needs. We present a laser-based cargo delivery platform that combines 11-ns laser pulses and structured flexible polymer substrates to create transient pores in the plasma membrane of cells. Cells are grown on the substrates, and pores are induced form on the cells in the regions excited with nanosecond laser pulses—thus, allowing treatment selectivity in a population. The medium surrounding the cell contains the delivery cargoes in solution, and cargoes diffuse into the cell before the transient pores are sealed. Polymer-based substrates are a promising material for laser-based delivery methods because they are low-cost, have flexible spatial movements, and have simple fabrication techniques. We deliver cargos of various sizes. We use fluorescence imaging and flow cytometry to quantify the delivery efficiency and viability in a reproducible manner. We obtain delivery efficiencies of up to 40% with viabilities of 60% for calcein green in adherent cells such as HeLa and Panc-1. We also deliver molecules of up to 40 kDas and siRNA. We use scanning electron microscopy to study cell adherence and substrate surface morphology. Our data shows that polymer-based substrates can deliver biological material directly into cells in a cost-effective manner.
Efficient drug and biomolecular delivery into cells is an important area of biomedical research. Intracellular delivery relies on porating cell membranes to allow exterior molecules to enter the cell efficiently and viably. Various methods, including optoporation, electroporation, and viral techniques, can deliver molecules to cells, but come with significant drawbacks such as low efficiency, low throughput, and low viability. We present a new laser-based delivery method that uses laser pulses to excite plasmonic, Titanium Nitride (TiN) microstructures for cell poration and offers high efficiency, throughput, and viability. TiN is a promising plasmonic material for laser-based delivery methods due to its high levels of hardness and thermal stability. We fabricate these microstructures by sputtering thin films of TiN on patterned sapphire substrates. We then optimize plasmonic enhancement and stability by investigating different fabrication conditions. We deliver dye molecules, siRNA, and microspheres to cells to quantify poration efficiency and viability by using flow cytometry and by imaging the target cells at defined time intervals post laser irradiation. Additionally, we study temperature effects via simulations and experiments, as well as oxidation of the TiN films over time. We also use scanning electron microscopy (SEM) techniques to study microstructure damage and cell adhesion. Overall, TiN presents a promising opportunity for use as a reusable material in future biomedical devices for intracellular biomolecular delivery and regenerative medicine.