Biomechanical properties of carbodiimide crosslinked collagen: influence of the formation of ester crosslinks.

There is a growing interest in the use of collagen matrices for tissue engineering. To prevent rapid degradation and to improve their mechanical properties, collagen matrices have been modified using different crosslinking agents. Among the different agents used, water soluble carbodiimides (such as N'-(3-dimethylaminopropyl)-N-ethylcarbodiimide, EDC) in combination with N-hydroxysuccinimide (NHS) are attractive systems, because no additional chemical entities are incorporated in the matrix.

Quantification of carboxyl groups in carbodiimide cross-linked collagen sponges.

Glutaraldehyde (GA) fixation of bioprosthetic tissue is a well adapted technique, with commercial products on the market for almost 40 years. Amine groups present in tissue react with GA to form different types of cross-links. An estimation of the degree of cross-linking of the tissue can be obtained by measuring the concentration of residual amine groups, which is frequently carried out with the 2,4,6 trinitrobenzene sulphonic acid (TNBS) assay.

Reduction of calcification of carbodiimide-processed heart valve tissue by prior blocking of amine groups with monoaldehydes.

Background And Aim Of The Study: Failure of implanted bioprostheses due to calcification is a commonly occurring phenomenon. In order to prevent calcification, many alternative cross-linking methods to glutaraldehyde (GA) have been developed and evaluated.

Methods: In a novel approach an improved carbodiimide (EDC) cross-linking method that comprises a two-step process was developed.

Diamine-extended glutaraldehyde- and carbodiimide crosslinks act synergistically in mitigating bioprosthetic aortic wall calcification.

Background And Aim Of The Study: The extension of glutaraldehyde (GA) crosslinks with diamine bridges was shown previously to reduce bioprosthetic heart valve calcification to a significant degree. The aim of the present study was to investigate whether the additional crosslinking of functional carboxyl groups could augment this anticalcific effect at the low glutaraldehyde concentrations typically used in commercial heart valve production.

Methods: Entire aortic roots of medium-sized pigs were fixed after 48 h of cold storage.

Reduced calcification of bioprostheses, cross-linked via an improved carbodiimide based method.

Glutaraldehyde fixation of bioprosthetic tissue has been used successfully for almost 40 years. However, it is generally recognized that glutaraldehyde fixation of bioprostheses is associated with the occurrence of calcification. Accordingly, many efforts have been undertaken to develop techniques for the fixation of bioprostheses, which will not lead to calcification.

Optimization of diamine bridges in glutaraldehyde treated bioprosthetic aortic wall tissue.

Objective: Bioprosthetic calcification can be significantly mitigated by both increased concentrations of glutaraldehyde (GA) and the introduction of diamine (DA) bridges. The purpose of the present study was to evaluate whether an optimal effect of DA-enhanced fixation can be achieved by titration of dialdehyde and diamine concentrations.

Methods: Porcine aortic roots were fixed at 0.