Preparation and Application of Zwitterion Modified Starch Catalyzed by HRP‐ACAC Binary System

Enzymatic modification, compared with traditional starch (St) chemical modification methods, avoids using toxic solvents and toxic catalysts. The horseradish peroxidase (HRP), being the most commonly employed natural green initiator, has found extensive application in starch grafting modification as a substitute for chemical initiators. HRP‐catalyzed grafting of starch with vinyl zwitterionic monomers has not been reported. Here, modified starch (St‐PSBMA) is first synthesized by grafting zwitterionic sulfobetaine [2‐(Methacryloyloxy)ethyl]dimethyl‐(3‐sulfopropyl) (SBMA) onto starch by HRP/Acetylacetone(ACAC) binary initiation system catalyzed. The modified starch‐based hydrogel is then prepared by the repeated freeze‐thaw method. Compared with native starch‐based hydrogels, which bind water molecules only through hydrogen bonding, the ability of modified starch‐based hydrogels to bind water molecules is enhanced by ionic solvation. The modified starch hydrogels also have excellent antiprotein adsorption and antibacterial properties due to the presence of a strong hydration layer. The modified starch‐based hydrogel also has excellent sensitivity and stability when used as a sensor for detecting joint motion. The binary HRP initiating system, employed in this study instead of the traditional three‐component HRP initiating system, offers a novel and promising approach for grafting modification of starch without the need for strong oxidant hydrogen peroxide.