Effect of the Electric field on the Biomineralization of Collagen

Abstract

Collagen/hydroxyapatite hybrids are promising biomimetic materials that can replace or temporarily substitute bone tissues. The present work is focused on evaluating an electric field's effect on collagen biomineralization using a double-diffusion system. The methodological principle consisted in applying an electric field on the incubation medium to promote the opposite migration of ions into collagen membranes and produce hydroxyapatite (HA). Two physically separated solutions were used for the incubation medium, one rich in phosphate ions (solution A) and the other in calcium ions (solution B), and their effect was evaluated against the use of Simulated Body Fluid (SBF). Moreover, taking advantage of the polarizability properties of collagen, the benefits of pre-polarizing the organic membranes and the effect of incubation time were also assessed. Our results proved that the electric field, the membrane pre-polarization, and the ion's physical separation significantly accelerate the mineralization process of collagen. FTIR and Raman structure analysis confirmed the formation of HA after biomineralization and allowed to determine the mineralization degree of the synthesized samples quantitatively. It was found that the application of the electric field influenced the collagen structure and its interactions with the mineral phase. The increment of the mineralization degrees proved to enhance the photoluminescence properties of the collagen/HA materials. However, the electric properties, including the dielectric constant and conductivity, were reduced with the increment of the mineral deposition. These results might provide a useful approach for future applications in manufacturing biomimetic bone-like materials.