Characterization of Polyanionic Collagen Prepared by Selective Hydrolysis of Asparagine and Glutamine Carboxyamide Side Chains

Abstract

Acellular polyanionic collagen materials intended for biomaterial and tissue engineering uses were prepared by the selective and controlled hydrolysis of carboxyamides from asparagine and glutamine residues of type I collagen present in pericardium, tendon, and intestinal submucosa, all from bovine origin. The increase in carboxyl groups was from 26 +/- 14 (12 h of hydrolysis) to 134 +/- 12 (144 h of hydrolysis). Although collagen triple helix structure of polyanionic materials was preserved in all cases, a decrease in thermal stability and a gradual loss in the ability of collagen molecules to form fibrils were detected with increasing carboxyl content, probably as a result of changes in the pattern of electrostatic interaction. The resulting materials were basically acellular polyanionic collagen matrixes associated with an elastin content dependent on the time of hydrolysis. The results showed that the procedure described in this work may be a useful process for preparation of collagen biomaterials with variable physicochemical properties and macromolecular arrangement with respect to fibril formation and with potential use in tissue engineering.

Porcine skin as a source of biodegradable matrices: alkaline treatment and glutaraldehyde crosslinking

“…Three independent determinations showed that the elastin content after alkaline hydrolysis and GA crosslinking does not change independent of the reaction time and GA concentration. Alkaline hydrolysis removes cells, in addition to other components present in the tissue, resulting in an acellular matrix composed of collagen and elastin [7] . So, it was possible to obtain the elastin and collagen mass percentage.…”

“…Collagen matrices can be chemically modified due to their large quantities of reactive groups such as amines (NH 2 ), carboxylic acids (COOH) and hydroxyl (OH); allowing the implementation of different structural, mechanic and physico-chemical properties, making possible new applications in the biomaterials field. One possible chemical modification is the selective hydrolysis of carboxyamide groups of asparagine and glutamine residues present in type I collagen [7] . This modification generates a negatively charged matrix at pH 7.4, with a total increase up to 134 ± 12 negative charges per tropocollagen unit after 96 hours of hydrolysis [7] .…”

“…One possible chemical modification is the selective hydrolysis of carboxyamide groups of asparagine and glutamine residues present in type I collagen [7] . This modification generates a negatively charged matrix at pH 7.4, with a total increase up to 134 ± 12 negative charges per tropocollagen unit after 96 hours of hydrolysis [7] . Collagen matrices obtained by alkaline hydrolysis of bovine pericardium were highly biocompatible, and in rat tibia experiments, the material incorporated in the tissue with an absence of a chronic inflammatory response [8,9] .…”

New ferrimagnetic biocomposite film based in collagen and yttrium iron garnet

“…The materials obtained were equilibrated with a solution containing Na 2 SO 4 , NaCl, KCl and CaSO 4 (6 ml of solution/g of tissue) for 12 h and the salt excess was removed as described earlier [12]. The materials was suspended in deionized water, had its pH adjusted at 3.5 with pure acetic acid and the mixture was homogenized in a blender.…”

Implantação de biomembrana de colágeno tratada em solução alcalina ou conservada em glicerina a 98% na parede abdominal de equinos

“…GOISSIS et al (1999) utilizaram solução alcalina em tecidos animais, promovendo hidrólise dos grupos carboxiamidas e aumentando até 106 cargas negativas por unidade de tropocolágeno. Essas alterações na estrutura do colágeno reduziram a antigenicidade tecidual e estimularam o crescimento celular (BET et al, 2001). A caracterização físico-química por espectroscopia na região do infravermelho demonstrou que a estrutura em hélice tripla do tropocolágeno foi preservada durante a hidrólise, ou seja, a unidade molecular do colágeno não foi alterada durante o processamento (GOISSIS et al, 1999).…”