Ag Nanoparticle-Decorated Oxide Coatings Formed via Plasma Electrolytic Oxidation on ZrNb Alloy

Abstract

Plasma electrolytic oxidation (PEO) can provide an ideal surface for osteogenic cell attachment and proliferation with further successful osteointegration. However, the same surface is attractive for bacteria due to similar mechanisms of adhesion in prokaryotic and eukaryotic cells. This issue requires the application of additional surface treatments for effective prevention of postoperative infectious complications. In the present work, ZrNb alloy was treated in a Ca-P solution with Ag nanoparticles (AgNPs) for the development of a new oxide layer that hosted osteogenic cells and prevented bacterial adhesion. For the PEO, 0.5 M Ca(H2PO2)2 solution with 264 mg L−1 of round-shaped AgNPs was used. Scanning electron microscopy with energy-dispersive x-ray and x-ray photoelectron spectroscopy were used for morphology and chemical analysis of the obtained samples; the SBF immersion test, bacteria adhesion test, and osteoblast cell culture were used for biological investigation. PEO in a Ca-P bath with AgNPs provides the formation of a mesoporous oxide layer that supports osteoblast cell adhesion and proliferation. Additionally, the obtained surface with incorporated Ag prevents bacterial adhesion in the first 6 h after immersion in a pathogen suspension, which can be an effective approach to prevent infectious complications after implantation.

In Vitro Biological Characterization of Silver-Doped Anodic Oxide Coating on Titanium

“…On the basis of the obtained results analysis and previous investigations, we can conclude that, after the PEO process, an oxide layer composed of titanium oxide and calcium phosphates was formed [ 41 ]. In the case of process conducted in the AgNP electrolytes, the oxide layer was enriched in silver, which was in the form of oxide [ 28 , 42 , 43 ]. Numerous data demonstrate the antibacterial effect of AgNPs incorporated into PEO coatings, but in most studies, AgNP use decreased the biocompatibility of implants [ 24 , 28 ].…”

“…In the case of process conducted in the AgNP electrolytes, the oxide layer was enriched in silver, which was in the form of oxide [ 28 , 42 , 43 ]. Numerous data demonstrate the antibacterial effect of AgNPs incorporated into PEO coatings, but in most studies, AgNP use decreased the biocompatibility of implants [ 24 , 28 ]. The principal idea of the current research was loading of the implant surface with an antibacterial agent (AgNPs) to kill planktonic bacteria in implant tissue and to prevent bacterial adhesion and biofilm development.…”

“…It has been shown that the various components of the electrolyte can impact formation of the oxide layers and deposition of the desired components [ 27 ]. Different nanoparticles (NPs) have been incorporated into classical calcium–phosphate PEO solutions to provide functional antibacterial effects, but some research still demonstrates different toxicity levels [ 28 ]. It should be noted that AgNP incorporation via PEO can prevent the release of Ag ions into the bloodstream due to immobilization of AgNPs deep inside the oxide layer and can prevent expected toxic effects [ 29 ].…”

Formation of a Bacteriostatic Surface on ZrNb Alloy via Anodization in a Solution Containing Cu Nanoparticles

“…Some researchers have effectively anodized an alloy containing Zr and Nb, which opens up perspectives for the wide application of PEO for medical implant production [15]. To enhance antibacterial properties of the modified surface, antibiotics [33] and silver nanoparticles [23] have been added to the PEO solution. Despite the antibacterial effect, antibiotics and AgNPs exhibit different levels of toxicity that limited their application for clinical use [21], stimulating the development of new ways to overcome the current limitations.…”

“…These properties indicate that CuNPs could be a promising alternative to silver. The PEO method has been already used to produce dental implant Ag-doped surfaces on Ti substrates [23], but there is no information about CuNPs applied for ZrNb implant treatment. Substantial evidence is needed to estimate the antimicrobial properties and biocompatibility of the ZrNb alloy treated with PEO.…”