Triggered Gas-Generating Microcapsules For Fast Controlled Drug Release

Althought PLGA has been demonstrated for improving the therapeutic efficacies of anticancer drugs for years, the releasing of drug is still limited by the inherent physical properties of it. In order to increase the local effective therapeutic concentration of drugs as well as to minimize toxicity and side effects, we designed a drug delivery system which could liberate a larger amount of cargos instantaneously.Briefly, we formulated a novel kind of PLGA microcapsule which containing IR-780 and doxorubicin (DOX) in the shell and the liquid perfluorohexane (PFH) as the core. After exposure to NIR, perfluorohexane could be easily vaporized owing to the IR-780-induced local temperature rise.The PFH bubble may activate the microcapsules for significant volumetric expansion or even break the PLGA shells to promote the release of chemotherapeutic agents [171.In addition, the phase transition at Tg from the glassy state to the rubbery state can provide a large scale movement for the polymer chains, thus significantly increasing the free volume of the polymeric matrix that is directly proportional to the drug release rate. In vitro, cancer cells incubated with DOX/IR-780/PFH-loaded microcapsules and irradiated with NIR light display significantly great cytotoxic effects owing to the NIR triggered rapid drug release. Therefore, our microcapsules can overcome the inherent disadvantage of PLGA and serve as a promising delivery system for controllable rapid drug release.For its perfect biocompatibility and low immunogenicity, collagen is widely used in tissue engineering, medical devices and drug delivery systems recent years. The preparation and purification procedures of type ? collagen from fresh pigskin was researched. The SDS-Polyacrylamide gel electrophoresis (SDS-PAGE) and the fourier transform infrared (FTIR) spectroscopy had been used to study the secondary structure of the collagen prepared. The SDS-PAGE profile and FTIR spectra of the collagen were consistent with the Sigma standard collagen type ? which means that the collagen prepared was type ?.