Characterization and application of carboxylate-type zwitterions synthesized by one-step

Zwitterions have been attracting great attention and the synthesis of carboxylate-type zwitterions is complicated than those of sulfonate-type zwitterions. Therefore, we focused on one-step synthesis of carboxylate-type zwitterions with a lactone, reported in 1974. Since functional zwitterions as a category of ionic liquids are emerging materials, the characteristics and applications of the zwitterions were not studied. In this study, the one-step synthesis of carboxylate-type zwitterions was re-evaluated and characterize the biochemical and physico-chemical properties to explore potential and limitation of the synthesis. One-step synthesis of a carboxylate-type zwitterion was reproduced with sufficient purity. Although we found the emergence of a side product, which has not been reported in 1974, the side product was removed through successive hydrolysis. A liquid zwitterion, an emerging class of zwitterions, was also synthesized through the procedure. The one-step synthesis was confirmed to be useful and some characteristics of the synthesized zwitterions were similar to typical zwitterions. The synthesized zwitterion dissolved hardly-soluble cellulose with the aid of a co-solvent. On the other hand, the synthesized zwitterions have relatively low thermal stability and the low thermal stability suggests that the synthesized zwitterions have to be applied at mild temperatures, e.g. protein solvents and electrolytes. We here proposed the synthesized zwitterion as a cryoprotectant for mammalian cells as one of feasible applications. MDCK cells were well cryopreserved by the 10 wt% zwitterion aqueous solution.