Silver activation on thin films of Ag–ZrCN coatings for antimicrobial activity

Abstract

Nowadays, with the increase of elderly population and related health problems, knee and hip joint prosthesis are being widely used worldwide. However, failure of these invasive devices occurs in a high percentage thus demanding the revision of the chirurgical procedure. Within the reasons of failure, microbial infections, either hospital or subsequently-acquired, contribute in high number to the statistics. Staphylococcus epidermidis (S. epidermidis) has emerged as one of the major nosocomial pathogens associated with these infections. Silver has a historic performance in medicine due to its potent antimicrobial activity, with a broad-spectrum on the activity of different types of microorganisms. Consequently, the main goal of this work was to produce Ag-ZrCN coatings with antimicrobial activity, for the surface modification of hip prostheses. Thin films of ZrCN with several silver concentrations were deposited onto stainless steel 316 L, by DC reactive magnetron sputtering, using two targets, Zr and Zr with silver pellets (Zr+Ag target), in an atmosphere containing Ar, C2H2 and N2. The antimicrobial activity of the modified surfaces was tested against S. epidermidis and the influence of an activation step of silver was assessed by testing samples after immersion in a 5% (w/v) NaClO solution for 5 min. The activation procedure revealed to be essential for the antimicrobial activity, as observed by the presence of an inhibition halo on the surface with 11 at.% of Ag. The morphology analysis of the surface before and after the activation procedure revealed differences in silver distribution indicating segregation/diffusion of the metallic element to the film's surface. Thus, the results indicate that the silver activation step is responsible for an antimicrobial effect of the coatings, due to silver oxidation and silver ion release.

Antibacterial Metallic Touch Surfaces

“…For example, Chu et al [48] observed that the antimicrobial performance of Ag-containing ZrTiAl and AlAgTi thin films is similar to that of a pure Ag coating. In several other studies Ag was incorporated as an element in thin films [49,50,51] to tune the antimicrobial performance, but the alteration of another parameter (roughness, size of crystal formation, etc.) makes it difficult to assess whether the killing effectiveness can be only attributed to compositional differences.…”

“…In order to promote Ag ionisation, the oxidising compound sodium hypochlorite can be used in Ag-containing coatings. This process is called silver activation and has been successfully used to promote the antimicrobial effect of the coatings [49]. Another method for eliminating pathogens, photocatalysis disinfection using ultraviolet light, involves promoting the release of reactive oxygen species resulting from redox reactions at the surface of the TiO 2 films [59]; this also has self-cleaning properties [59,60,61].…”

Hip prosthesis biomaterials: a challenge in prevention of biofilm formation

“…Biomaterials used on hip arthroplasties were researched to identify their possible influence on biofilm formation prevention on hip prosthesis. The presence of factors that interfere on biofilm formation was evidenced: metal roughness, antibiotic coatings action, difference in biofilm adhesion on distinct biomaterials, ions action, different concentrations of titanium and silver, coating activity of HD-CLPE(VE) with PMPC and acylase activity in disrupting quorum-sensing signals (RAMAGE et al, 2003;PARVIZI et al, 2004;TOMÁŠ;NACHTNEBL;OTIEPKA, 2007;HENRIQUES et al, 2009;HOSMAN et al, 2009HOSMAN et al, , 2011NURYASTUTI et al, 2011;GÓMEZ-BARRENA et al, 2012;NEUT et al, 2012NEUT et al, , 2015LASS et al, 2014;FERRERI et al, 2015;KYOMOTO et al, 2015;GROVER et al, 2016).…”

“…Various studies were performed to develop and evaluate new coatings with the ability to minimize microbial colonization (PARVIZI et al, 2004;HENRIQUES et al, 2009;LEWIS et al, 2010;NEUT et al, 2012NEUT et al, , 2015FERRERI et al, 2015;KYOMOTO et al, 2015;GROVER et al, 2016). Silver-zirconium carbonitride (Ag-ZrCN) thin films and cross-linked polyethylene combined with vitamin E-blended and a poly(2methacryloyloxyethyl phosphorylcholine) layer -(HD-CLPE(VE) with PMPC) coatings presented antimicrobial activity (FERRERI et al, 2015;KYOMOTO et al, 2015). Moreover, the biomaterial developed with an acylase-containing polyurethane coating disrupted quorum-sensing signals 1397 Hip prosthesis biomaterials… MARQUES, D. M. et al responsible by communication and progression of biofilm formation (GROVER et al, 2016).…”

Macrophages adhesion rate on Ti-6Al-4V substrates: polishing and DLC coating effects

“…Different materials have been used as coatings on implants in order to improve cell adhesion and to prevent their wear, such as: ultra-fine hydroxyapatite powders (Kaya, 2008), carbon nanotubes (Kaya, 2008), Ag-ZrCN films (Ferreri et al, 2015) and DLC films (Casiraghi et al, 2005). All these coatings have shown good results, however only the DLC thin film has been considered able to promote a reduction on metal friction at the same time that increases the wear resistance, the hardness, and the cell adhesion rate (Grill et al, 1988;Grill, 2003;Ianno et al, 1995;Jelinek et al, 2016;Khatir et al, 2015;Marciano et al, 2009).…”