Poloxamer surfactant preserves cell viability during photoacoustic delivery of molecules into cells.

Efficient intracellular delivery of molecules is needed to modulate cellular behavior for laboratory and medical applications, but is often limited by trade-offs between achieving high intracellular delivery and maintaining high cell viability. Here, we studied photoacoustic delivery of molecules into cells by exposing DU145 human prostate carcinoma cells to nanosecond laser pulses in the presence of carbon black nanoparticles. Under strong laser exposure conditions, less than 30% of cells were viable and exhibited uptake. Addition of poloxamer surfactant at those laser exposure conditions increased cell viability to almost 90%, with intracellular uptake in >80% of cells. This remarkable increase in efficiency of intracellular delivery and cell viability may be attributed to enhanced cell membrane resealing by poloxamer surfactant after photoacoustic delivery. While F-68 poloxamer was effective, the larger, more-hydrophobic F-127 poloxamer provided the best results. There was no significant protective effect from addition of Ca(2+) , BAPTA-AM, ATP, fetal bovine serum or glycine betaine, which were expected to promote active cell membrane repair mechanisms and other active intracellular protective processes. We conclude that poloxamer surfactant preserves cell viability during photoacoustic delivery of molecules into cells, thereby enabling highly efficient intracellular delivery.