Influence of surface charge on the in vitro protein adsorption and cell cytotoxicity of paclitaxel loaded poly(ε-caprolactone) nanoparticles

The biokinetic fate of polymeric nanoparticles in the physiological milieu is strongly influenced by its properties such as size, surface charge and surface affinity. The electrostatic properties of the polymeric nanoparticles and, thereby, the reliant properties such as cellular interactions, reactivity and toxicity, can be tailored by modulating the surface charge. Therefore, the present study aimed at studying the influence of surface charge on the physicochemical properties, in vitro protein adsorption and cell cytotoxicity of poly(ε-caprolactone) (PCL) nanoparticles (NPs). Paclitaxel loaded PCL nanoparticles were obtained by emulsion solvent evaporation extraction technique and differently charged using ionic surfactants. The NPs were characterized for size, zeta potential, morphology, entrapment and release. In vitro protein adsorption and cytotoxicity of NPs with different surface charge was investigated. The prepared NPs were rounded with a smooth surface and had a particle size less than 250 nm with narrow distribution and high entrapment efficiency (>80%). The zeta potential of the particles varied between −22 mV and +16 mV depending on its composition. The in vitro protein adsorption studies revealed that positively charged NPs adsorbed more proteins than other formulations. The cytotoxicity studies on MCF-7 cells exhibited that positively charged NPs engender the highest cell inhibition due to preferential uptake based on electrostatic interactions with cell membranes. The results suggest that surface charge could be undeniably significant in determining the protein adsorption and cellular interactions and must be intently considered during the design of colloidal particles to impart better performance in the physiological system.