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Acta Biomater. 2016 Sep 1;41:110-8. doi: 10.1016/j.actbio.2016.05.026. Epub 2016 May 18.

Collagen-collagen interactions mediated by plant-derived proanthocyanidins: A spectroscopic and atomic force microscopy study.

Author information

1
College of Dentistry, University of Illinois at Chicago, 801 South Paulina Street, Chicago, IL 60612, USA.
2
Department of Chemistry, University of Illinois at Chicago, 845 West Taylor Street, Chicago, IL 60607, USA.
3
Biomedical Engineering Department, McCormick School of Engineering, Northwestern University, Technological Institute, 2145 Sheridan Road, Evanston, IL 60208, USA.
4
Biomedical Engineering Department, McCormick School of Engineering, Northwestern University, Technological Institute, 2145 Sheridan Road, Evanston, IL 60208, USA; Departments of Materials Science and Engineering and Bioengineering, College of Engineering, University of California, 210 Hearst Mining Building, Berkeley, CA 94720-1760, USA.
5
College of Dentistry, University of Illinois at Chicago, 801 South Paulina Street, Chicago, IL 60612, USA. Electronic address: bedran@uic.edu.

Abstract

Collagen cross-linkings are determinant of biological tissue stability and function. Plant-derived proanthocyanidins (PACs) mimic different hierarchical levels of collagen cross-links by non-enzymatic interactions resulting in the enhancement to the biomechanics and biostability of collagen-rich tissues such as dentin. This study investigated the interaction of PACs from Vitis vinifera grape seed extract with type I collagen in solubilized form and in the demineralized dentin matrix (DDM) by fluorescence spectral analysis; collagen-collagen binding forces in presence of cross-linking solutions by atomic force microscopy (AFM); and spectroscopic analysis of the DDM using attenuated total reflectance Fourier transform-infrared spectroscopy (ATR-FTIR). Glutaraldehyde (GA) and carbodiimide hydrochloride (EDC) with known cross-linking mechanisms were selected for comparative analyses. Changes in fluorescence upon interaction of solubilized type I collagen with PACs, EDC and GA reflected pronounced modifications in collagen conformation. PACs also promoted stronger collagen-collagen fibrils interaction than EDC and GA. A new feature was observed using ATR-FTIR spectroscopic analysis in PACs-treated collagen and DDM. The findings suggest covalent interactions between collagen and PACs. The mechanisms of interaction between PACs-collagen hold attractive and promising tissue-tailored biomedical applications and the binding forces that potentially drive such interaction were characterized.

STATEMENT OF SIGNIFICANCE:

Connective tissues such as skin, bone and dentin are mainly composed of type I collagen, which is cross-linked to promote tissue stability, strength and function. Novel therapies using substances that mimic cross-links have been proposed to promote repair of collagen-based-tissues. In dentistry, naturally occurring proanthocyanidins (PACs) have the potential to enhance dentin mechanical properties and reduce its enzymatic degradation, but their mechanisms of cross-linking are unclear. The present study investigated the specific interactions between PACs-type I collagen in purified and dentin collagen and compared to the well described cross-linking mechanisms promoted by synthetic chemical substances. Findings reveal that covalent-like bonds are induced by plant PACs in type I collagen as well as in complex dental native tissue, promoting strong collagen-collagen interactions.

KEYWORDS:

ATR-FTIR spectroscopy; Atomic force microscopy; Collagen cross-linking; Dentin; Proanthocyanidins

PMID:
27208639
PMCID:
PMC4983101
DOI:
10.1016/j.actbio.2016.05.026
[Indexed for MEDLINE]
Free PMC Article

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