Maghemite nanoparticles and their protamine derivatives: cellular internalization and effects on cell-cycle progress.

Dimercaptosuccinic acid-coated maghemite nanoparticles and their protamine derivatives were prepared. TEM revealed that the average size of nanoparticles is 10 nm and derivatives with larger size consist of several original nanoparticles. The cellular uptake of nanoparticles and derivatives by human hepatoma cells, and their effects on cell viability and cell-cycle were detected. Results showed that the internalization of nanoparticles into cells was very limited, while derivatives could be internalized into cells with high efficiency. Nanoparticles didn't display significant cytotoxicity at a wide range of concentrations (0.3-2.4 mg/ml), whereas derivatives had a narrow range of non-toxicity concentrations (0.3-0.6 mg/ml). Both nanoparticles and derivatives could affect cell-cycle progress and the mechanisms underlying were discussed.