Phosphorylcholine-based stealthy nanocapsules enabling tumor microenvironment-responsive doxorubicin release for tumor suppression.

The efficient delivery of anticancer drugs into tumor tissues to improve therapeutic efficacy remains an urgent demand. To satisfy this demand, a drug delivery system based on a stealthy nanocapsule was developed. This nanocapsule was fabricated by encapsulating stealthy cross-linked poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) and benzaldehyde groups around the protein bovine serum albumin (BSA) followed by conjugation of doxorubicin (Dox) through a pH-responsive benzoic-imine bond. The in vitro results show that the Dox-conjugated nanocapsule (nBSA-Dox) released the drug under an acidic tumor microenvironment (pH ~6.5) and killed HepG2 human liver cancer cells. The half-life of Dox conjugated to nBSA in mice was significantly prolonged, and the area-under-curve of plasma Dox of the mice treated with nBSA-Dox was as much as 242 fold of free Dox. The in vivo results confirmed that this nanocapsule efficiently accumulated in tumor tissue and significantly suppressed the tumor growth.