In this study, a Y-shaped amphiphilic block copolymer consisting of hydrophilic poly(ethylene glycol) (mPEG) and two poly(ε-caprolactone) (PCL) as the hydrophobic arms with a ketal linker was synthesized (mPEG-Ketal-(PCL) 2 ). The structure of the copolymer with different compositions was characterized by 1 H NMR, gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). The amphiphilic property endows the copolymer with the ability to be self-assembled into micelles for encapsulating anticancer drug doxorubicin (DOX), and the effect of copolymer with different PCL length on drug loading properties were tested. The morphology, size, pH responsiveness, drug release profile and in vitro anticancer activity of the DOX loaded micelles were also studied. In vitro drug release studies showed that over 50% of the DOX was released at pH 5.0 in 24 h because of hydrolysis of ketal linker in the copolymers. The confocal laser microscopy and flow cytometry experiments showed that the DOX-loaded micelles could be effectively internalized by Hela cells, the ketal bond in the backbone was broken in acid endo/lysosomal compartments and triggered the fast release of DOX. The in vitro antitumor efficacy of the DOX loaded mPEG-Ketal-(PCL) 2 micelles was better than that of non-pH sensitive ones. In vivo studies showed that the mPEG-Ketal-(PCL) 2 micelles enhanced the DOX blood circulation time and had good tumor-targeting efficiency.
3D printing has been highly pursued owing to its effortless fabrication of custom-defined geometries, yet the integration of multi-material with diverse properties in one printed object remains challenging. In this work, a digital light 3D-printed polymer network that is capable of heterogeneous growth to seamlessly integrate multi-material is designed. This is accomplished through orthogonal photochemistry design, where visible light is utilized to initiate radical polymerization of acrylates for 3D printing. Inspired by plants’ phototropism due to uneven auxin distribution, UV light is employed to induce spatiotemporal catalyst generation for promoting network heterogeneous growth. In this process, it is found that the UV-generated catalyst effectively facilitates the hydrolysis of ketals to produce hydroxyls, which can further serve as “growing sites” to initiate the ring-opening polymerization of polycaprolactone. This enables precise manipulation of both shape and mechanical properties in 3D-printed objects. The distinctive heterogeneous growth mechanism of 3D printing enables the production of multi-material components using a single resin.
危险品化学品经营许可证（带存储）