A Novel Temperature‐Responsive Polymer as a Gene Vector

A temperature‐responsive polymer poly{2‐(dimethylamino)ethyl methacrylate‐co‐[cis‐butenedioic anhydride‐poly[(N‐isopropylacrylamide)‐co‐(butyl methacrylate)]]} (PDMNIB) was synthesized by free radical polymerization. The polymer had a significant temperature‐responsive behavior with a lower critical solution temperature (LCST) at 20 °C. Gel retardation assay showed that PDMNIB could efficiently interact with DNA. Dynamic light scattering (DLS) and zeta potential measurement indicated that the average sizes and the surface electric charges of the PDMNIB/DNA complexes could be changed by temperature. Due to the thermosensitive interaction between PDMNIB and DNA, the gene transfection efficiency of PDMNIB could be improved by temperature.

     

Robust and Adhesive Hydrogels from Cross‐Linked Poly(ethylene glycol) and Silicate for Biomedical Use

A systematic approach to develop robust and adhesive hydrogels by photopolymerizing poly(ethylene glycol) (PEG)‐diacrylate and methoxy‐PEG‐acrylate in the presence of charged silicate nanoparticles (Laponite) is presented. PEG‐diacrylate and silicate are used for covalent and physical cross‐linking, thus providing the hydrogel with mechanical and adhesive strengths. Methoxy‐PEG‐acrylate is used as a softening agent. The resulting hydrogels can be extensively elongated and the hydrogels readily adhere to tissue even in the elongated state. These hydrogels may aid the development of adhesive tissue engineering matrixes, wound dressings, sealants, and the adhesive components of biomedical devices.

     

Robust and Semi‐Interpenetrating Hydrogels from Poly(ethylene glycol) and Collagen for Elastomeric Tissue Scaffolds

Here we present an injectable PEG/collagen hydrogel system with robust networks for use as elastomeric tissue scaffolds. Covalently crosslinked PEG and physically crosslinked collagen form semi‐interpenetrating networks. The mechanical strength of the hydrogels depends predominantely on the PEG concentration but the incorporation of collagen into the PEG network enhances hydrogel viscoelasticity, elongation, and also cell adhesion properties. Experimental data show that this hydrogel system exhibits tunable mechanical properties that can be further developed. The hydrogels allow cell adhesion and proliferation in vitro. The results support the prospect of a robust and semi‐interpenetrating biomaterial for elastomeric tissue scaffolds applications.

     

Synthesis of thiazolo[3,2‐d][1,2,4] triazines through palladium‐catalyzed heteroannulation of acetylenic compounds

The reaction of 6‐methyl‐5‐(prop‐2‐ynylthio)‐5,6‐dihydro‐1,2,4‐triazin‐3(4H)‐one 1 with various iodobenzenes 2 in the presence of palladium catalyst leads to the formation of substituted triazolotriazines.