Conferring Antioxidant Activity to an Antibacterial and Bioactive Titanium Surface through the Grafting of a Natural Extract

Abstract

The main unmet medical need of bone implants is multifunctional activity, including their ability to induce rapid and physiological osseointegration, counteract bacterial biofilm formation, and prevent in situ chronic inflammation at the same time. This research starts from an already developed c.p. titanium surface with proven bioactive (in vitro hydroxyl apatite precipitation) and antibacterial activities, due to a calcium titanate layer with nano- and micro-scale roughness and loaded with iodine ions. Here, antioxidant ability was added to prevent chronic inflammation by grafting polyphenols of a green tea extract onto the surface, without compromising the other functionalities of the surface. The surface was characterized before and after functionalization through XPS analysis, zeta potential titrations, ion release measurements, in vitro bioactivity tests, SEM and fluorescence microscopy, and Folin–Ciocalteu and biological tests. The presence of grafted polyphenols as a homogeneous layer was proven. The grafted polyphenols maintained their antioxidant ability and were anchored to the surface through the linking action of Ca2+ ions added to the functionalizing solution. Iodine ion release, cytocompatibility towards human mesenchymal stem cells (hMSC), and antibacterial activity were maintained even after functionalization. The antioxidant ability of the functionalized surface was effective in preserving hMSC viability in a chemically induced pro-inflammatory environment, thus showing a scavenger activity towards toxic active species responsible for inflammation.

Development, Analytical Characterization, and Bioactivity Evaluation of Boswellia serrata Extract-Layered Double Hydroxide Hybrid Composites

“…A specific role of boswellic acids has been also clarified regarding their antioxidant properties, as they are involved in the inhibition of the pro-inflammatory NF-κB activator and in the modulation of other relevant inflammatory molecular targets, such as AP-1 and β-catenin, as well as enzymes like COX-2 and pro-inflammatory cytokines (TNF-α, IL-1β) [ 45 ]. Accordingly, a pro-inflammatory condition was induced by oxidative stress chemically generated by hydrogen peroxide addition into the culture medium; afterwards, supernatants were collected and used to cultivate cells, as previously reported by the authors [ 46 , 47 , 48 ]. In such a pro-inflammatory scenario, the well-known scavenger ability of the boswellic acids [ 49 , 50 ] was expected to significantly reduce the amount of the cytotoxic oxygen- and nitrogen-derived (ROS) active species, thus protecting cells from intracellular accumulation.…”

“…The composites’ ability to act as antioxidants via scavenging activity was evaluated regarding their ability to protect cells from the intracellular accumulation of toxic active species in a pro-inflammatory scenario. Accordingly, oxidative stress was chemically induced by adding hydrogen peroxide (H 2 O 2 , 3 h/day, 300 μM) into the medium to generate oxygen-derived toxic active species (ROS), as previously shown by the authors [ 46 , 47 , 48 ]. Accordingly, H 2 O 2 was added to the medium in the presence of the composites and agitated (100 rpm) at room temperature for 3 days.…”

Pioneering nanomedicine in orthopedic treatment care: a review of current research and practices

“…The latter could help reduce the risk of infections in medical implants. Particles could be designed with a targeting ability to destroy bacteria and, at the same time, minimize the risk of developing resistance to bacteria (Cazzola et al, 2023;Gamna et al, 2024). However, there are disadvantages to consider as well.…”

“…One must observe such changes in the performance of medical implants. Further studies and developments will need to be done to optimize such surfaces for safety and effectiveness (Cazzola et al, 2023;Gamna et al, 2024).…”

Laser-Induced Fabrication of Micro-Optics on Bioresorbable Calcium Phosphate Glass for Implantable Devices

“…The enhanced dissolution rate of the laser-modified region could be attributed to the depolymerization of the glass network due to the P − O bond cleaving upon photon absorption. Finally, in addition to the bioresorbability of the phosphate glass, the presence of antibacterial ions, such as copper, in the glass network could potentially contribute to the antibacterial property of the glass [49][50][51][52]. Thus, the controlled laser structuring of micro-optics on the Cu-doped calcium phosphate glass network would simultaneously provide a multifunctional capability in both diagnostics followed by the delivery of therapeutic agents (Cu 2+ ions) upon dissolution after the intended optical functionality.…”