Conjugating curcumin to water soluble polymer stabilized gold nanoparticles via pH responsive succinate linker.

Curcumin is a natural product with immense medicinal assets. The low aqueous solubility and consequent poor bioavailability of curcumin are the most serious limitations to its utilization as a potential therapeutic agent. In order to enhance the aqueous solubility and bioavailability of the drug, we covalently conjugated curcumin onto the surface of gold nanoparticles (AuNPs) aided by a water soluble polymer via a succinate linker. Conjugation of curcumin was confirmed by fluorescence, FTIR, 1H NMR and UV-Visible spectroscopy and XRD studies. The size and surface charge of the AuNPs were determined by DLS, and the morphology was visualized by TEM. Aqueous solubility of curcumin was augmented upon conjugation with the polymer stabilized AuNPs. The pH responsive release of curcumin from the nano-vehicle ensures safer delivery of the drug at physiological pH. Cytotoxic potential and cellular uptake of curcumin conjugated AuNPs were assessed by MTT assay and fluorescence microscopy, respectively, using C6 glioma cancer cells. Thus, the curcumin conjugated polymer stabilized AuNPs circumvent limitations of curcumin and can find applications in pH responsive drug delivery.