Reversible conformational changes in the parallel type G-quadruplex structure inside a thermoresponsive hydrogel.

The novel property of reversible regulation of parallel type G-quadruplexes with moderate temperature changes was discovered in thermoresponsive hydrogels using a universal chiroptical spectrophotometer 1 (UCS-1). This study is the first to report the regulation of the ssDNA steric structure by using a poly(N-isopropylacrylamide) (PNIPAAm) gel.

Design of Tetra-arm PEG-crosslinked Thermoresponsive Hydrogel for 3D Cell Culture.

We synthesized poly(N-isopropylacrylamide) gel containing cell-adhesive peptides, RGDS pendants, and crosslinked by a hydrophilic polymer. Since gelation occurs by simply mixing the polymers, cells can be simultaneously encapsulated inside the gel during gelation. This gel has roughly a 15% volume change between 25 and 37°C, and is transparent at both temperatures. Moreover, adhesion of encapsulated C2C12 cells to the gel could be observed. This thermoresponsive gel would be potentially useful as a cell culture material that can control cell fate by changing mechanical properties of the cell's external environment.