Characterization and cell material interactions of PEGylated PNIPAAM nanoparticles.

The aim of this study was to investigate the haemocompatibility of poly(N-isopropylacrylamide)-co-poly(ethylene glycol), PNIPAAM-PEG based nanoparticles and the influence of poly(ethylene glycol), PEG on the interactions of nanoparticles with cells. To achieve this purpose, thermosensitive PNIPAAM-PEG nanoparticles were synthesized by free radical dispersion polymerization method. Optimized nanosystems had particle sizes less than 200 nm, low polydispersity and LCST of 40-41 degrees C. The nanoparticles also showed nearly 83% encapsulation efficiency for doxorubicin HCl with temperature dependent release. Presence of PEG resulted in reduced protein adsorption by more than 50% in comparison to non-PEG containing nanoparticles. Protein adsorption was noted to be dependent on PEG chain length and was the least with M(n)=4000. The particles up to a concentration of 2mg/ml did not show any toxicity on J774 and L929 cell lines. No interactions were observed when NIPAAM-PEG nanoparticles were incubated with blood cells viz. RBCs, neutrophils, platelets and the coagulation system suggesting their haemocompatibility.