A fast and versatile cross-linking strategy via o-phthalaldehyde condensation for mechanically strengthened and functional hydrogels  

作　　者：Zhen Zhang Chaoliang He Yan Rong Hui Ren Tianran Wang Zheng Zou Xuesi Chen 

机构地区：[1]CAS Key Laboratory of Polymer Ecomaterials,Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,Changchun 130022,China [2]University of Science and Technology of China,Hefei 230026,China [3]University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《National Science Review》2021年第4期109-119,共11页国家科学评论（英文版）

基　　金：supported by the National Natural Science Foundation of China(51622307,21574127,51973218 and51833010);the Youth Innovation Promotion Association,CAS。

摘　　要：Fast and catalyst-free cross-linking strategy is of great significance for construction of covalently cross-linked hydrogels.Here,we report the condensation reaction between o-phthalaldehyde(OPA)and N-nucleophiles(primary amine,hydrazide and aminooxy)for hydrogel formation for the first time.When four-arm poly(ethylene glycol)(4 a PEG)capped with OPA was mixed with various N-nucleophile-terminated 4 aPEG as building blocks,hydrogels were formed with superfast gelation rate,higher mechanical strength and markedly lower critical gelation concentrations,compared to benzaldehyde-based counterparts.Small molecule model reactions indicate the key to these cross-links is the fast formation of heterocycle phthalimidine product or isoindole(bis)hemiaminal intermediates,depending on the N-nucleophiles.The second-order rate constant for the formation of phthalimidine linkage(4.3 M-1s-1)is over 3000 times and 200 times higher than those for acylhydrazone and oxime formation from benzaldehyde,respectively,and comparable to many cycloaddition click reactions.Based on the versatile OPA chemistry,various hydrogels can be readily prepared from naturally derived polysaccharides,proteins or synthetic polymers without complicated chemical modification.Moreover,biofunctionality is facilely imparted to the hydrogels by introducing amine-bearing peptides via the reaction between OPA and amino group.

关 键 词：superfast gelation o-phthalaldehyde chemistry versatile cross-linking functional hydrogel reaction kinetics 

分 类 号：TQ427.26[化学工程]