Modulation of silver nanoparticle cytotoxicity with thermoresponsive polymer surface coatings

There is great interest in better understanding the complex interactions between engineered nanoparticles and biological systems. In this study, the effect of variable surface chemistry on silver nanoparticle induced cytotoxicity and cell uptake was investigated. L929 fibroblasts were incubated with silver nanoparticles coated with the thermoresponsive copolymer poly(MEO₂MA-co-OEGMA) at monomer ratios of 80:20, 90:10 and 95:5. Microscopic images show that higher MEO₂MA content in the nanoparticle coating leads to enhanced aggregation at 37°C. Silver nanoparticle induced cytotoxicity was assessed by LDH assay and the highest cytotoxic response was elicited by nanoparticles with 95% MEO₂MA in the surface coating. Similarly, cell uptake of nanoparticles was highest with nanoparticles with 95% MEO₂MA and progressively diminished as the ratio of MEO₂MA:OEGMA decreased.