Preparation and Self-Assembly of pH-Responsive Hyperbranched Polymer Peptide Hybrid Materials.

In recent years, the coupling of structurally and functionally controllable polymers with biologically active peptide materials to obtain polymer-peptide hybrids with excellent properties and biocompatibility has led to important research progress in the field of polymers. In this study, a pH-responsive hyperbranched polymer hPDPA was prepared by combining atom transfer radical polymerization (ATRP) with self-condensation vinyl polymerization (SCVP) using a three-component reaction of Passerini to obtain a monomeric initiator ABMA containing functional groups. The pH-responsive polymer peptide hybrids hPDPA/PArg/HA were obtained by using the molecular recognition of polyarginine (ß-CD-PArg) peptide modified with ß-cyclodextrin (ß-CD) on the hyperbranched polymer, followed by the electrostatic adsorption of hyaluronic acid (HA). The two hybrid materials, h1PDPA/PArg12/HA and h2PDPA/PArg8/HA could self-assemble to form vesicles with narrow dispersion and nanoscale dimensions in phosphate-buffered (PB) at pH = 7.4. The assemblies exhibited low toxicity as drug carriers of ß-lapachone (ß-lapa), and the synergistic therapy based on ROS and NO generated by ß-lapa had significant inhibitory effects on cancer cells.

Synthesis and Self-Assembly of Hyperbranched Multiarm Copolymer Lysozyme Conjugates Based on Light-Induced Metal-Free Atrp.

In recent years, the coupling of structurally and functionally controllable polymers with biologically active protein materials to obtain polymer-protein conjugates with excellent overall properties and good biocompatibility has been important research in the field of polymers. In this study, the hyperbranched polymer hP(DEGMA-co-OEGMA) was first prepared by combining self-condensation vinyl polymerization (SCVP) with photo-induced metal-free atom transfer radical polymerization (ATRP), with 2-(2-bromo-2-methylpropanoyloxy) ethyl methacrylate (BMA) as inimer, and Di (ethylene glycol) methyl ether methacrylate (DEGMA) and (oligoethylene glycol) methacrylate (OEGMA, Mn = 300) as the copolymer monomer. Then, hP(DEGMA-co-OEGMA) was used as a macroinitiator to continue the polymerization of a segment of pyridyl disulfide ethyl methacrylate (DSMA) monomer to obtain the hyperbranched multiarm copolymers hP(DEGMA-co-OEGMA)-star-PDSMA. Finally, the lysozyme with sulfhydryl groups was affixed to the hyperbranched multiarm copolymers by the exchange reaction between sulfhydryl groups and disulfide bonds to obtain the copolymer protein conjugates hP(DEGMA-co-OEGMA)-star-PLZ. Three hyperbranched multiarm copolymers with relatively close molecular weights but different degrees of branching were prepared, and all three conjugates could self-assemble to form nanoscale vesicle assemblies with narrow dispersion. The biological activity and secondary structure of lysozyme on the assemblies remained essentially unchanged.

Effect of Er:YAG Laser Etching on the Shear Bond Strength and Microleakage of Self-Glazed Zirconia Ceramics.

Objective: To investigate the effect of Er:YAG laser irradiation on the shear bond strength (SBS) and microleakage of self-glazed zirconia (SZ) ceramics. Background: SZ is a novel type ceramic; laser irradiation has started to be used in the surface treatment of different ceramics, while SZ has been rarely studied to improve the bond quality. Methods: One hundred twenty blocks (5 mm × 5 mm × 5 mm) of SZ ceramics were produced and split into eight groups following different surface treatments (n = 15): Group A: no treatment; Group B: standard grid processing; and Group C-H: different Er:YAG laser power settings (100, 200, 300, 400, 500, and 600 mJ). Ten blocks of each group received the measurement of SBS and fracture mode analysis, three blocks underwent the evaluation of the microleakage depths, and the other two blocks were observed under the scanning electronic microscopy (SEM). Results: Group F obtained the highest SBS and the lowest microleakage depth without damaging the ceramic surface structure, which was statistically significant compared with the control group and gridding group (p < 0.05), whereas the difference was not statistically significant (p > 0.05) between group E and group F. The results of bonding performance were consistent with failure types and observation of surface characterizations in SEM images. Conclusions: According to the results here, Er:YAG irradiation had effect on surface treatment. In addition, 400 mJ Er:YAG could increase the SBS and decrease the microleakage depth on SZ ceramics without damaging the surface structure.