Mesoporous zirconia surfaces with anti-biofilm properties for dental implants

Abstract

Cytocompatible bioactive surface treatments conferring antibacterial properties to osseointegrated dental implants are highly requested to prevent bacteria-related peri-implantitis. Here we focus on a newly designed family of mesoporous coatings based on zirconia (ZrO2) microstructure doped with gallium (Ga), exploiting its antibacterial and pro-osseo-integrative properties. The ZrO2 films were obtained via sol–gel synthesis route using Pluronic F127 as templating agent, while Ga doping was gained by introducing gallium nitrate hydrate. Chemical characterization by means of x-ray photoelectron spectroscopy and glow discharge optical emission spectroscopy confirmed the effective incorporation of Ga. Then, coatings morphological and structural analysis were carried out by transmission electron microscopy and selected area electron diffraction unveiling an effective stabilization of both the mesoporous structure and the tetragonal ZrO2 phase. Specimens’ cytocompatibility was confirmed towards gingival fibroblast and osteoblasts progenitors cultivated directly onto the coatings showing comparable metabolic activity and morphology in respect to controls cultivated on polystyrene. The presence of Ga significantly reduced the metabolic activity of the adhered oral pathogens Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans in comparison to untreated bulk zirconia (p < 0.05); on the opposite, Ga ions did not significantly reduce the metabolism of the oral commensal Streptococcus salivarius (p > 0.05) thus suggesting for a selective anti-pathogens activity. Finally, the coatings’ ability to preserve cells from bacterial infection was proved in a co-culture method where cells and bacteria were cultivated in the same environment: the presence of Ga determined a significant reduction of the bacteria viability while allowing at the same time for cells proliferation. In conclusion, the here developed coatings not only demonstrated to satisfy the requested antibacterial and cytocompatibility properties, but also being promising candidates for the improvement of implantable devices in the field of implant dentistry.

Gallium-Based Liquid Metal Materials for Antimicrobial Applications

“…Likewise, Agostino et al [ 131 ] took advantage of the antibacterial and osseointegration properties of Ga and fabricated mesoporous zirconia (ZrO 2 ) materials with Ga coating. The results showed that the existence of Ga 3+ dramatically reduced the metabolism of oral symbiotic Streptococcus salivarius and Aggregatibacter actinomycetemcomitans ( P. gingivalis and A. actinomycetemcomitans ) along with confirming the protective effect of Ga coating on cells against bacterial infestation The protective effect of Ga coating on cells against bacterial infection was also confirmed.…”

Team Approach: Metal Hypersensitivity in Total Joint Arthroplasty

“…Hypoallergenic implants offer several benefits over traditional implants beyond decreased immunogenicity. The design objective is to reduce infection risk because hypoallergenic implants are made from materials that resist bacterial growth [34][35][36] . Furthermore, they may reduce prosthetic-related complications because they can be absorbed fully by the body.…”

Antibacterial titanium dioxide coatings for CoCrMo orthopaedic implants

“…Silver nitrate is a common source of silver ions, whose impact on bacteria and human cells is well known [55,56]. Recently, the ability of gallium nitrate to prevent the formation of biofilm and to eradicate was already assessed [23,24]. On the basis of previous studies [57,58], MIC (minimal inhibitory concentration) of silver and gallium has been considered to prepare effective antibacterial coatings.…”

“…A possible method to provide CoCrMo alloys with antimicrobial properties is to develop coatings integrating cations with well-known antibacterial behaviour [16,17], such as silver (Ag) [18,19], copper (Cu) [20], zinc [20,21] and gallium (Ga) [22][23][24]. Among them, Ag has aroused lively interest in the biomedical field as well as some applications have reached the maturity for clinical use [25,26].…”

“…The renowned antibacterial activity of Ag, although the working mechanisms are not fully known, is attributed to the interaction between the positive charge of the Ag ions and the anionicity of the cell membrane and DNA structure of bacteria [27]. In addition to Ag, recent studies indicated that Ga possesses bactericidal properties thanks to its capability of inhibiting biofilm formation [24] owing to its ability to mimic the iron's action in several mechanisms in bacteria metabolism [28].…”