Effect of grafting ratio of poly(propylene imine) dendrimer onto gold nanoparticles on the properties of colloidal hybrids, their DOX loading and release behavior and cytotoxicity.

Abstract

A facile method via "grafting to" approach was used to synthesize hybrid gold-dendrimer nanoparticles. To this end, gold nanoparticles (GNPs) were synthesized via Turkevich method and 5th-generation cystamine-cored poly(propylene imine) (PPI) dendrimer was synthesized by iterative Michael addition and hydrogenation reactions. To prepare hybrid nanoparticles, aqueous solution of dendrimer was poured into colloidal solution of GNPs to form gold-S interactions which resulted in hybrid gold-dendrimer nanoparticles. UV-VIS-NIR and Raman spectroscopies, dynamic light scattering (DLS), thermogravimetric analysis (TGA) and field-emission scanning electron microscopy (FE-SEM) were utilized to confirm the surface modification of GNPs by PPI dendrimer. Cytotoxicity study through MTT assay against human fibroblast (FBS) cells showed appropriate proliferation of cells in presence of hybrid nanoparticles whereas higher grafting ratio of dendrimers induced more toxicity due to existence of peripheral amine groups. Also, hybrid gold-dendrimer nanoparticles were used as DOX nanocarriers. Results showed that carriers did not release the drug at pH = 7.4 significantly while up to 92.8% of drug release was measured at pH = 5.3. Also, higher grafting ratio limited the drug release due to shielding effect of grafted dendrimers.