Size-transformable gelatin/nanochitosan/doxorubicin nanoparticles with sequentially triggered drug release for anticancer therapy

The translation of nanoparticles in cancer treatment is limited by their low drug-loading capacity, poor colloidal stability, insufficient tumor penetration, and uncontrolled drug release. Herein, gelatin/nanochitosan/doxorubicin nanoparticles (GND) are developed by crosslinking nanochitosan (NCT) with gelatin for doxorubicin delivery. The hydrophilicity and stability properties of GND allow it to be protected and have a long circulation time in blood. The GND formulation exhibited shedding and triggered release effects as well as improved colloidal stability. When reaching the tumor site, matrix metallopeptidase-2 (MMP-2) from the tumor environment degrades gelatin from 178-nm GND to release smaller 4 nm nanochitosan/doxorubicin (ND) nanoparticles for deep tumor penetration and efficient tumor cell endocytosis. Following endocytosis by tumor cells, the intracellular low pH and MMP-2 further trigger doxorubicin release, resulting in superior inhibitory capacity against cancer cells. Using a mouse tumor-bearing model, the superior anticancer activity and good in vivo biocompatibility of GND were verified. The rational design of tumor-penetrating GND enables MMP-2/pH sequentially triggered intelligent drug delivery, providing a practical approach for anticancer therapy.