Grafting of Gallic Acid onto a Bioactive Ti6Al4V Alloy: A Physico-Chemical Characterization

Abstract

Despite increasing interest in the use of natural biomolecules for different applications, few attempts of coupling them to inorganic biomaterials are reported in literature. Functionalization of metal implants with natural biomolecules could allow a local action, overcoming the issue of low bioavailability through systemic administration. In the present work, gallic acid was grafted to a pre-treated Ti6Al4V in order to improve its biological response in bone contact applications. The grafting procedure was optimized by choosing the concentration of gallic acid (1 mg/mL) and the solvent of the solution, which was used as a source for functionalization, in order to maximize the amount of the grafted molecule on the titanium substrate. The functionalized surfaces were characterized. The results showed that functionalization with Simulated Body Fluid (SBF) as solvent medium was the most effective in terms of the amount and activity of the grafted biomolecule.A key role of calcium ions in the grafting mechanism is suggested, involving the formation of coordination compounds formed by way of gallic acid carboxylate and Ti-O − as oxygenated donor groups. Bioactive behavior and surface charge of the pre-treated Ti6Al4V surface were conserved after functionalization. The functionalized surface exposed a greater amount of OH groups and showed higher wettability.

Improvements of alveolar bone healing using Moringa oleifera leaf powder and extract biomimetic composite: an experimental study in dogs

“…Polyphenols decrease inflammatory mediators, such as histamine, and cytokines. Consequently decrease bone resorption 29,[34][35][36] Chlorogenic acid, rutin and ferulic acid had osteoprotective function by promoting bone mineral density. [37][38][39][40][41] Gallic acid in an in-vivo study showed positive effects around implants .…”

“…[37][38][39][40][41] Gallic acid in an in-vivo study showed positive effects around implants . 35 Catechin, green tea polyphenols also promotes osteogenesis .42 Syringic acid stimulates stem cells into osteoblasts, and it could be an osteogenic compound. 44 Cinnamic acid could be a part of osteogenic stimulant composite.…”

Repositioning Natural Antioxidants for Therapeutic Applications in Tissue Engineering

“…Similarly, a sponge-like scaffold with different cross-linking chemistry was shown to induce osteogenesis of UMR106 osteoblasts in vitro and in vivo in calvarian defect as a result of EGCG action [ 207 ]. Gallic acid, another antioxidant, was incorporated in titanium substrate in order to deliver it for potential bone contact application [ 238 ]. The possibility to functionalize hydroxyapatite with Qu by different chemical syntheses for bone regeneration was explored in a triple co-culture model comprising MG63 osteoblast-like in contact with the biomaterial, osteoclast precursors 2T-110, and HUVECs [ 201 ].…”

Enhancement of Biomimetic Enzymatic Mineralization of Gellan Gum Polysaccharide Hydrogels by Plant-Derived Gallotannins

“…For the mineralization, various biomolecules have been used, including polyphenols, which have been successfully used for prevention and treatment of osteoporosis due to their protective effects on the bone mineral density [12,13]. In addition, polyphenols promoted biological mineralization of Ti6Al4V alloy by deposition of hydroxyapatite by mesenchymal stem cells cultured on this implant material, which is currently used in clinical practice [14]. In our earlier studies, polyphenols promoted mineralization of chitosan and gellan gum hydrogels (i.e., other materials that are promising for bone tissue engineering [15,16].…”

“…Due to the increasing prevalence of antibiotic-resistant bacteria, endowing biomaterials for implantation with antibacterial properties is desirable. Since gallotannins have shown antibacterial activity [14,26], they are expected to be promising antibacterial materials.…”