Cytotoxicity Evaluation Of Temperature Sensitive Poly(n-isopropylacrylamide) Nanoparticles For Drug Delivery

The objective of this research project was to develop temperature sensitive poly(N-isopropylacrylamide) (PNIPA) nanoparticles for drug delivery applications. These nanoparticles were formulated by a radical polymerization method, and their toxicity was studied in vitro using MTS assays and various cell types such as fibroblasts, smooth muscle cells, and endothelial cells. Cytotoxicity results did not show a significant difference in cell survival when cells were exposed to different particle sizes (100, 300, and 500 nm). In addition, dose studies of 100 nm nanoparticles showed that the cells exposed to PNIPA nanoparticles at concentrations less than or equal to 5 mg/ml were biocompatible. Photomicrographs also showed that cells exposed to PNIPA nanoparticles maintained their normal morphology. Additionally, we improved the biocompatibility of PNIPA nanoparticles using various Pluronic surfactants (L64, P65, P85, and F127) instead of the common surfactant, sodium dodecyl sulfate (SDS). The MTS assay results of free surfactant toxicity studies showed that Pluronic surfactants, especially F127 and P85, were more biocompatible than SDS over the studied range of concentrations. We also found that PNIPA nanoparticles synthesized using Pluronic were more biocompatible than those of SDS. Finally, drug release studies were done using Doxorubicin as a drug model. PNIPA nanoparticles synthesized using Pluronic surfactants produced higher amount of Doxorubicin release than PNIPA nanoparticles synthesized using SDS at 37oC over the same period of time. In general, Pluronic P85 and F127 used as surfactants to formulate temperature sensitive PNIPA nanoparticles increase the biocompatibility drug release of PNIPA nanoparticles.