Yunfeng Shi,Mengyue Wang,Linzhu Zhou,Xueqi Shen,Jinhao Wang,Nannan Mo,Guo Zhao,Su Yang,Xinyuan Zhu,Andrew M. Smith
A new strategy for the construction, release and cellular imaging application of triethylamine-responsive fluorescent quantum dots (QDs) based on supramolecular self-assembly has been described. The supramolecular self-assembly (HPEI/SA), which was constructed through the electrostatic interactions between terminal amine groups of hyperbranched polyethylenimines (HPEI) and carboxylic acid groups of stearic acid (SA), first captured aqueous Zn 2+ ions into the hydrophilic dendritic core and subsequently encapsulated QDs/S 2- by the complexation interactions and reactions between Zn 2+ and S 2- on QDs. Due to the pH-responsive property of the HPEI/SA supramolecular self-assembly, the fluorescence of encapsulated QDs is sensitive to the triethylamine/SA mole ratio, and the encapsulated QDs can be released to the aqueous phase by cleaving HPEI/SA. The resulting fluorescent QDs/HPEI nanocomposites show promising prospects in bioimaging.
An injectable polyethylene glycol (PEG) hydrogel was successfully prepared via borate–catechol complexation using dopamine functionalized 4-armed PEG (4-arm-PEG-DA) and phenylboronic acid modified 4-armed PEG (4-arm-PEG-PBA). The hydrogel was formed within 10 s by mixing 15 wt% 4-arm-PEG-DA with 15 wt% 4-arm-PEG-PBA buffer solutions at pH 9.0. The hydrogel was characterized by Fourier transform infrared (FT-IR) spectroscopy, rheological measurements, scanning electron microscopy (SEM) and lap shear strength tests. Furthermore, pH, glucose and dopamine responsiveness of the hydrogel based on phenylborate–catechol complexation was demonstrated by degradation experiments and drug release tests. The lap shear strength tests indicated that the hydrogel possessed the ability of self-healing which was bestowed by the phenylborate–catechol dynamic covalent bond. Moreover, the hydrogel could serve as a decent bio-adhesive due to its adhesion properties on different substrates especially the porcine skin. In vitro cytotoxicity tests demonstrated the excellent cytocompatibility of the hydrogel. The results of all the experiments indicate that our newly developed multi-functionalized hydrogel can have potential applications in biomedical fields such as drug delivery, tissue engineering, and bio-adhesives.
Yi Sun,Wei Zhang,Shan Lu,Wenhua Miao,Meiling Chen,Fei Liu,Haining Na,Jin Zhu
Herein, a novel cellulose-based fluorescent material with amine-responsive property was developed in a CO 2 switchable solvent for the contactless, real-time, and visual monitoring of the freshness of shrimp , crab, and fish. A nucleophilic cellulose carbonate intermediate is in-situ formed upon dissolution of cellulose in the CO 2 switchable solvent, which is adopted for the highly effective grafting of poly( l -lactic acid) and amine-responsive fluorescent reagent 7-amino-4-(trifluoromethyl) coumarin onto the cellulose backbone via ring opening polymerization and nucleophilic substitution reaction, respectively. The product has good processibility, and sensitive and reversible fluorescent responsive towards ammonia. The fluorescent intensity of the material decreased significantly and its fluorescent color changed from blue to cyan, when the aquatic products got spoiled. This study indicates that the CO 2 switchable solvent has great potential for the modification of cellulose with various functionality by taking advantage of the highly active nucleophilic cellulose carbonate intermediate.
危险品化学品经营许可证（带存储）