Assisted mineralization ability of proanthocyanidins in collagen scaffold and dentin

To assess the potential mechanisms of an enriched Vitis vinifera (Vve) in mediating mineralization using both constituted type-1 collagen scaffolds and dentin matrix substrate.

An enriched formulation of oligomeric proanthocyanidins - Vve was compared to untreated substrates (C) and glutaraldehyde-treated substrate (GA). Biomineralization protocols included a simulated body fluid - SBF and a Ca-P supersaturated solutions for collagen scaffold and dentin matrix studies, respectively. Analytical methods included mineral content (FTIR), thermal behavior (DSC), crystal formation and Ca/P atomic ratio of crystal-like structure (SEM-EDS and TEM), and Ca²⁺ concentration (Ca-ISE). Data were statistically analyzed using one-way ANOVA and post-hoc tests (α=0.05).

Untreated and Vve groups showed a higher amount of mineral normalized to the amount of collagen than the GA group (p < 0.007 and p < 0.019 respectively). Untreated and Vve-treated collagen scaffolds exhibited similar cumulative Ca²⁺ uptake (18.2 and 17.7 µg) and GA-treated scaffold had lower (15.8 µg). After 4 days in SBF solution, the highest endothermic peak was found at 81.4°C for Vve, followed by 78.7°C for GA and 57.6°C for untreated collagen. SEM-EDS analysis showed a well-organized layer of apatite crystals deposited around the collagen fibrils. Vve treatment promoted broad crystal nucleation over fibrils in a collagen scaffold. Unlike the GA-treated group, where fewer and sparsely distributed crystals were found, Vve group exhibited a thick and organized mineral layer over the dentin matrix.

Biomineralization occurs via a self-assembly process by which apatite crystals are deposited in an orderly fashion over the organic matrices of innate dentin. Vve may assist mineralization by preservation of the nucleation sites over the matrices modulating the rate of formation of apatite crystals.