New pH-sensitive nanogels based on Boltorn® H40 and poly(vinylpyridine) for delivery of hydrophobic anticancer drugs

In this study, we describe the synthesis of a new structure of pH-sensitive H40 based nanogel by click reaction through mini-emulsion polymerization. The nanogels were synthesized by cross coupling of H40-poly(ε-caprolactone) (H40-PCL) dendrimers as cores and poly(vinylpyridine) (PVP) as a pH sensitive crosslinker. The poly(ethylene glycol) (PEG) pendant group was introduced at the middle of PVP chains as hydrophilic segment to act as hydrophilic shell at final nanogel for better dispersity. Folic acid that is conjugated at the end of some of PEG through the free carboxyl group was used for targeting cancer cells that overexpress folate receptors.These nanogels are pH-sensitive and swelling ratio of the nanogels is closely relevant to the pH of environment. In this intracellular delivery method, the nanogel was exposed to low-pH environments of cytosol that triggered the nanogel to swell and release the drug