Insight into the molecular properties of Chitlac, a chitosan derivative for tissue engineering.
Chitlac is a biocompatible modified polysaccharide composed of a chitosan backbone to which lactitol moieties have been chemically inserted via a reductive N-alkylation reaction with lactose. The physical-chemical and biological properties of Chitlac that have been already reported in the literature suggest a high accessibility of terminal galactose in the lactitol side chain. This finding may account for its biocompatibility which makes it extremely interesting for the production of biomaterials. The average structure and the dynamics of the side chains of Chitlac have been studied by means of NMR (nuclear Overhauser effect and nuclear relaxation) and molecular dynamics to ascertain this hypothesis. A complete assignment of the (1)H and (13)C NMR signals of the modified polysaccharide has been accomplished together with the determination of the apparent pKa values of the primary and secondary amines (6.69 and 5.87, respectively). NMR and MD indicated a high mobility of Chitlac side chains with comparable average internuclear distances between the two techniques. It was found that the highly flexible lactitol side chain in Chitlac can adopt two distinct conformations differing in the orientation with respect to the polysaccharide chain: a folded conformation, with the galactose ring parallel to the main chain, and an extended conformation, where the lactitol points away from the chitosan backbone. In both cases, the side chain resulted to be highly hydrated and fully immersed in the solvent.
Bracco Imaging SpA-CRB Trieste, AREA Science Park, Building Q, SS 14, km 163.5, 34149 Basovizza (Trieste), Italy.
Nicola
N
D'Amelio
Carmen
C
Esteban
Anna
A
Coslovi
Luigi
L
Feruglio
Fulvio
F
Uggeri
Myriam
M
Villegas
Julio
J
Benegas
Sergio
S
Paoletti
Ivan
I
Donati
D000900:Anti-Bacterial Agents / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D002236:Carbohydrate Conformation; D048271:Chitosan / Q000031:analogs & derivatives / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D056004:Molecular Dynamics Simulation; D012995:Solubility; D013696:Temperature; D023822:Tissue Engineering
D000900:Anti-Bacterial Agents; D001672:Biocompatible Materials; D048271:Chitosan