The dextran‐allyl isocyanate/poly(N‐isopropylacrylamide) (Dex‐AI/PNIPAAm) hydrogel was designed and prepared by copolymerization of the modified dextran with N‐isopropylacrylamide (NIPAAm). This novel Dex‐AI/PNIPAAm hydrogel is biodegradable and intelligent due to its biodegradable dextran linkage and thermosensitive PNIPAAm moiety. With an increase in dextran content, it exhibits the increased lower critical solution temperature (LCST) and decreased porous microstructure. Also, the thermosensitivity of this hydrogel is also controllable and adjustable depending on the different compositions.
SEM micrographs of the Dex‐AI/PNIPAAm hydrogels. 相似文献
A biodegradable gene transfer vector, poly(ethylenimine)-grafted-poly[(aspartic acid)-co-lysine] has been developed by thermal polycondensation of aspartic acid and lysine, and branch poly(ethylenimine) (Mw less than 600) was grafted to the backbone. The polymer was characterized by ^1H NMR. It appeared lower cytotoxity compared to poly(ethylenimine) (25KDa),which was quantified by MTT assay. Electrophoresis indicated that the polymer could retardate DNA at N/P ratio 1.2-1.8 (w/w). Transfection efficiency of the complexes was studied in NT2 cell lines. It was 1.5 fold higher than molecular weight PEI (Mw=25KDa). 相似文献
Chemically crosslinked biodegradable hydrogels based on di-acrylated Pluronic F-127 tri-block copolymer were prepared by a photopolymerization method. Poly(lactic acid-co-glycolic acid) (PLGA) microspheres were physically entrapped within the Pluronic hydrogel in order to modulate the local pH environment by acidic degradation by-products of PLGA microspheres. The PLGA microspheres were slowly degraded to create an acidic microenvironment, which facilitated the cleavage of an acid-labile ester-linkage in the biodegradable Pluronic hydrogel network. The presence of PLGA microspheres accelerated the degradation of the Pluronic hydrogel and enhanced the protein release rate when protein was loaded in the hydrogel.SEM image of photo-crosslinked Pluronic hydrogel entrapping PLGA microspheres. 相似文献