Pluronic block copolymers: novel functions in ultrasound-mediated gene transfer and against cell damage.

Pluronics have been investigated as vectors for drug and gene delivery in vitro and in vivo and were demonstrated to have high efficiency for gene transfer in vivo. However, they alone do not enhance gene transfer in vitro. We examined three pluronics, F127, L61 and P85, for their effects on ultrasound (US)-mediated gene transfer in three cell lines, 3T3-MDEI, C2C12 and CHO. The polymers showed differential effects on cell viability and transfection efficiency in a dose-dependent manner. All the polymers were unable to facilitate gene transfer when used alone, but enhanced US-mediated gene transfer significantly at concentrations around the critical micelle concentration in the three cell lines. F127 showed no significant toxicity at any concentration and protected the cells against US-mediated damage at a high concentration. L61 decreased cell viability significantly in a dose-dependent manner, whereas P85 showed mild toxicity when its concentration was at or above 0.05%.