Studies on epoxy compound fixation

Abstract

Bioprostheses derived from collagenous tissues have to be fixed and subsequently sterilized before they can be implanted in humans. Clinically, the most commonly used fixative is glutaraldehyde. However, the tendency for glutaraldehyde to markedly alter tissue stiffness and promote tissue calcification are well-recognized drawbacks of this fixative. To address the deficiencies with the glutaraldehyde-fixed tissue, a new fixative, epoxy compound, was used to fix biological prostheses. The study was undertaken to investigate the fixation rates and crosslinking densities of biological tissues fixed with various epoxy compounds. These epoxy compounds are different in their chemical structures. Glutaraldehyde was used as a control. The fixation rates and crosslinking densities of the fixed tissues were determined by measuring their fixation indices and denaturation temperatures, respectively. Generally, the epoxy-fixed tissues were more pliable than the glutaraldehyde-fixed one. Furthermore, the tissues fixed with monofunctional epoxy compound were more pliable than those fixed with multifunctional epoxy compounds. With increasing pH or temperature, the fixation rate of epoxy compound increased. However, the number of epoxide functional groups did not seem to affect the fixation rate of the epoxy compound. The fixation rate of glutaraldehyde was faster than that of epoxy compounds. Additionally, the crosslinking density of the glutaraldehyde-fixed tissue was greater than that of the epoxy-fixed counterparts. Moreover, it was noted that the denaturation temperatures of the tissues fixed with glutaraldehyde or multifunctional epoxy compounds were significantly higher than the fresh ones (p < 0.05), while that fixed with monofunctional epoxy compound stayed roughly the same throughout the entire fixation process (p > 0.05). The results obtained in this study may be used to optimize the fixation process for developing bioprostheses fixed with epoxy compounds.

Kinetic Study of Modification of Collegen Peptide with Allyl Glycidyl Ether

“…Up to now, the kinetics and mechanism of epoxy compounds in the fixation of collagen have not been fully understood. A few studies deal with the kinetics of collagen modification using epoxy compounds in aqueous solutions [2,13].…”

The kinetics of 1,4-butanediol diglycidyl ether crosslinking of dermal sheep collagen

“…[20][21][22][23] Despite the large amount of research in this area, the kinetics of crosslinking of collagen materials with epoxy compounds have been described only briefly. 10,11 Tu et al crosslinked bovine internal thoracic arteries with the bifunctional ethylene diglycidylether and with the trifunctional glycerol polyglyc- idyl ether. Crosslinking was carried out at 37°C under basic conditions (pH 8.5, 9.5, or 10.5) using three different epoxy compound concentrations of 0.5, 1.0, and 4.0 wt %.…”

“…[9][10][11] These compounds, which have aldehyde, isocyanate, bisimido ester, and epoxide functional groups, respectively, react with the amine groups of (hydroxy)lysine residues present in the collagen. Despite the common use of these crosslinking agents for stabilization of the collagen component of biomaterials, few studies on reaction kinetics have been described in the literature.…”

“…A few studies deal with the kinetics of collagen crosslinking using epoxy compounds in aqueous solutions. 10,11 Also, extensive studies on amine-epoxy systems used in epoxy resins have been carried out. [12][13][14] Several kinetic models which describe the curing process were proposed and tested experimentally.…”

Toward safer thanatopraxy cares: formaldehyde‐releasers use

“…Epoxy compounds have been also tested in concentrations close to 4%, and seem to lead to a weaker hardening and better life‐like colour than dialdehydes (Sung et al. ; Alsharif et al. ; Ajileye et al.…”