Exploring the kinetics of gelation and final architecture of enzymatically cross-linked chitosan/gelatin gels

Biomacromolecules. 2015 Apr 13;16(4):1401-9. doi: 10.1021/acs.biomac.5b00205. Epub 2015 Mar 26.

Abstract

Small-angle neutron scattering (SANS) was used to characterize the nanoscale structure of enzymatically cross-linked chitosan/gelatin hydrogels obtained from two protocols: a pure chemical cross-linking process (C), which uses the natural enzyme microbial transglutaminase, and a physical-co-chemical (PC) hybrid process, where covalent cross-linking is combined with the temperature-triggered gelation of gelatin, occurring through the formation of triple-helices. SANS measurements on the final and evolving networks provide a correlation length (ξ), which reflects the average size of expanding clusters. Their growth in PC gels is restricted by the triple-helices (ξ ∼ 10s of Å), while ξ in pure chemical gels increases with cross-linker concentration (∼100s of Å). In addition, the shear elastic modulus in PC gels is higher than in pure C gels. Our results thus demonstrate that gelatin triple helices provide a template to guide the cross-linking process; overall, this work provides important structural insight to improve the design of biopolymer-based gels.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Biocatalysis
  • Chitosan / chemistry*
  • Cross-Linking Reagents / chemistry
  • Gelatin / chemistry*
  • Gels / chemistry*
  • Kinetics
  • Polymerization
  • Transglutaminases / chemistry*

Substances

  • Bacterial Proteins
  • Cross-Linking Reagents
  • Gels
  • Gelatin
  • Chitosan
  • Transglutaminases