title: Exploring the kinetics of gelation and final architecture of enzymatically cross-linked chitosan/gelatin gels.
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.
authors.affiliation: †King's College London, Institute of Pharmaceutical Science, 150 Stamford Street, London, SE1 9NH, United Kingdom.
authors.forename: Marcelo A
authors.initials: MA
authors.lastname: da Silva
authors.affiliation: †King's College London, Institute of Pharmaceutical Science, 150 Stamford Street, London, SE1 9NH, United Kingdom.
authors.forename: Franziska
authors.initials: F
authors.lastname: Bode
authors.affiliation: §LSS Group, Institut Laue-Langevin, 6 rue Jules Horowitz BP 156, F-38042 Grenoble, Cedex 9, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Grillo
authors.affiliation: †King's College London, Institute of Pharmaceutical Science, 150 Stamford Street, London, SE1 9NH, United Kingdom.
authors.forename: Cécile A
authors.initials: CA
authors.lastname: Dreiss
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry*; D055162:Biocatalysis; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents / Q000737:chemistry; D005780:Gelatin / Q000737:chemistry*; D005782:Gels / Q000737:chemistry*; D007700:Kinetics; D058105:Polymerization; D011503:Transglutaminases / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D005782:Gels; D005780:Gelatin; D048271:Chitosan; D011503:Transglutaminases