In this study, a facile method to fabricate reduction-responsive core-crosslinked micelles via in situ thiol-ene “click” reaction was reported. A series of biodegradable poly(ether-ester)s with multiple pendent mercapto groups were first synthesized by melt polycondensation of diol poly(ethylene glycol), 1,4-butanediol, and mercaptosuccinic acid using scandium trifluoromethanesulfonate [Sc(OTf)₃] as the catalyst. Then paclitaxel (PTX)-loaded core-crosslinked (CCL) micelles were successfully prepared by in situ crosslinking hydrophobic polyester blocks in aqueous media via thiol-ene “click” chemistry using 2,2′-dithiodiethanol diacrylate as the crosslinker. These PTX-loaded CCL micelles with disulfide bonds exhibited reduction-responsive behaviors in the presence of dithiothreitol (DTT). The drug release profile of the PTX-loaded CCL micelles revealed that only a small amount of loaded PTX was released slowly in phosphate buffer solution (PBS) without DTT, while quick release was observed in the presence of 10.0 mM DTT. Cell count kit (CCK-8) assays revealed that the reduction-sensitive PTX-loaded CCL micelles showed high antitumor activity toward HeLa cells, which was significantly higher than that of reduction-insensitive counterparts and free PTX. This kind of biodegradable and biocompatible CCL micelles could serve as a bioreducible nanocarrier for the controlled antitumor drug release. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 99–107

Fully degradable cationic poly(ester-phosphoester)s with antibacterial properties were prepared by a combination of ring-opening polymerization (ROP) and “click” reaction. First, poly(ester-phosphoester)s-bearing alkynyl groups were synthesized by the ring-opening copolymerization of 2-(2-propynyloxy)−2-oxo-1,3,2-dioxaphospholane (propynyl ethylene phosphate, PEP) and ε-caprolactone (CL) using lanthanum tris(2,6-di-tert-butyl-4-methylphenolate)s (La(DBMP)₃) as the catalyst. 2-Azido-N,N-dimethylethanamine (DMEAN₃) was then attached to the copolymers by “click” reaction, resulting in poly(ester-phosphoester)s with pendant tertiary amines. After the quaternization reactions between the copolymer and various alkyl bromides, cationic poly(ester-phosphoester)s containing ammonium groups were obtained. Optical density (OD) measurement shows that the cationic copolymers have excellent antibacterial activity, which makes them potential candidates as biomaterials. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42647.

Biodegradable poly(ester-phosphoester)s bearing multiple chloroethyl groups were synthesized facilely by the ring-opening copolymerization of 2-(2-chloroethoxy)-2-oxo-1,3,2-dioxaphospholane (CEP) and ε-caprolactone (CL) in the presence of lanthanum tris(2,6-di-tert-butyl-4-methylphenolate)s (La(DBMP)₃) as single-component catalyst under mild conditions. Then the quaternization reaction was carried out between the halide copolymers and a series of N,N-dimethyl alkylamines to give poly(ester-phosphoester)s containing ammonium groups with various charge density and alkyl chain length. The antibacterial properties of these cationic poly(esterphosphoester)s were evaluated by OD600 and zone of inhibition methods against gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria. Cationic poly(esterphosphoester)s with long alkyl chain on the ammonium groups show excellent antibacterial activity for both gram-negative and gram-positive bacteria even with low charge density. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3667–3673

Well-defined amphiphilic A₈B₄ miktoarm star copolymers with eight poly(ethylene glycol) chains and four poly(ε-caprolactone) arms (R-8PEG-4PCL) were prepared using “click” reaction strategy and controlled ring-opening polymerization (CROP). First, multi-functional precursor (R-8N₃-4OH) with eight azides and four hydroxyls was synthesized based on the derivatization of resorcinarene. Then eight-PEG-arm star polymer (R-8PEG-4OH) was prepared through “click” reaction of R-8N₃-4OH with pre-synthesized alkyne-terminated monomethyl PEG (mPEG-A) in the presence of CuBr/N,N,N′,N″,N″′- pentamethyldiethylenetriamine (PMDETA) in DMF. Finally, R-8PEG-4OH was used as tetrafunctional macroinitiator to prepare resorcinarene-centered A₈B₄ miktoarm star copolymers via CROP of ε-caprolactone utilizing Sn(Oct)₂ as catalyst at 100 °C. These miktoarm star copolymers could self-assemble into spherical micelles in aqueous solution with resorcinarene moieties on the hydrophobic/hydrophilic interface, and the particle sizes could be controlled by the ratio of PCL to PEG. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2824–2833.