Poly(2-oxazoline) block copolymer nanoparticles for curcumin loading and delivery to cancer cells

Curcumin, obtained from spice turmeric, is renowned for its anti-cancer activity, however, its use as a viable drug is impeded by its low aqueous solubility. To address this, we have investigated the potential of amphiphilic block copolymers, based on poly(2-alkyl-2-oxazoline)s (PAOx), as feasible nano-carriers for efficiently delivering curcumin to cancer cells. The block copolymers comprising hydrophobic and hydrophilic PAOx units in two different ratios were synthesized by cationic ring opening polymerization (CROP). The nanoparticles, ensuing from the self-assembly of the block copolymers in aqueous media, could encapsulate curcumin in their hydrophobic core. These curcumin loaded PAOx nanoparticles, of size around 100 rim, exhibited excellent stability and enhancement of aqueous solubility of curcumin. In vitro release studies demonstrated a pH sensitive release of curcumin from the PAOx nanoparticles. Profound cytotoxicity on C6 glioma cells, along with enhanced internalization of curcumin in these cells was achieved by the nanoparticle-mediated delivery. It was also revealed that the length of the hydrophobic block of the PAOx copolymers was functionally important. These systems offer potential clinical relevance as promising nano-carriers capable of circumventing the clinical limitations of curcumin.