ZnO nanoparticle incorporated nanostructured metallic titanium for increased mesenchymal stem cell response and antibacterial activity

Abstract

Recent trends in titanium implants are towards the development of nanoscale topographies that mimic the nanoscale properties of bone tissue. Although the nanosurface promotes the integration of osteoblast cells, infection related problems can also occur, leading to implant failure. Therefore it is imperative to reduce bacterial adhesion on an implant surface, either with or without the use of drugs/antibacterial agents. Herein, we have investigated two different aspects of Ti surfaces in inhibiting bacterial adhesion and concurrently promoting mammalian cell adhesion. These include (i) the type of nanoscale topography (Titania nanotube (TNT) and Titania nanoleaf (TNL)) and (ii) the presence of an antibacterial agent like zinc oxide nanoparticles (ZnOnp) on Ti nanosurfaces. To address this, periodically arranged TNT (80-120 nm) and non-periodically arranged TNL surfaces were generated by the anodization and hydrothermal techniques respectively, and incorporated with ZnOnp of different concentrations (375 μM, 750 μM, 1.125 mM and 1.5 mM). Interestingly, TNL surfaces decreased the adherence of staphylococcus aureus while increasing the adhesion and viability of human osteosarcoma MG63 cell line and human mesenchymal stem cells, even in the absence of ZnOnp. In contrast, TNT surfaces exhibited an increased bacterial and mammalian cell adhesion. The influence of ZnOnp on these surfaces in altering the bacterial and cell adhesion was found to be concentration dependent, with an optimal range of 375-750 μM. Above 750 μM, although bacterial adhesion was reduced, cellular viability was considerably affected. Thus our study helps us to infer that nanoscale topography by itself or its combination with an optimal concentration of antibacterial ZnOnp would provide a differential cell behavior and thereby a desirable biological response, facilitating the long term success of an implant.

Antimicrobial dental implant functionalization strategies —A systematic review

“…The overall antimicrobial efficiency of nanomaterials is however controversial. Some authors did not find a convincing decrease or even an increase in bacterial colonization on nanomaterials in comparison to untreated titanium 59,134,136,137) . Others found reductions in bacterial counts in vitro of up to 90% compared to commercially pure titanium on nano-Ti surfaces and of up to 100% for nano-AgHA when tested against E. coli, S. epidermidis and S. aureus [52][53][54][55][56]62,138) .…”

“…It has recently been shown that a titanium nanotube surface exhibited antimicrobial properties and down-regulated the glycosyltransferase genes of S. mutans 171) . All studies that tested surfaces with a combination of nanostructures and organic or inorganic antimicrobial chemical compounds on the nano-level found reduced bacterial adhesion and viability 31,34,43,[59][60][61][62]97,135,137) . Surfaces containing Ag NPs show excellent biocidal activity towards P. aeruginosa, S. oralis, S. mutans, P. gingivalis, S. aureus 143,144) , S.…”

A decomposable silica-based antibacterial coating for percutaneous titanium implant

“…Over the past few decades, the incorporation of antimicrobial agents, including antimicrobial peptides, cationic polymers, and inorganic metallic nanoparticles, at the location of the titanium implants has been sparsely investigated. [15][16][17][18][19][20] These methods have been well established to possess sustained antimicrobial properties. For instance, Chen et al successfully incorporated titanium implant surfaces with an antimicrobial peptide melamine coating that significantly reduced biofilm formation.…”

Nanoparticulate Platforms for Targeting Bone Infections: Meeting a Major Therapeutic Challenge

“…In this context, silver nanoparticles either isolated or associated with HA are the most frequent coating materials (Table 2). However, both zinc oxide and titanium oxide nanoparticles have also been used [61,63]. Elizabeth et al reported the coating of a nanostructured titanium implant with zinc oxide nanoparticles [61].…”

“…However, both zinc oxide and titanium oxide nanoparticles have also been used [61,63]. Elizabeth et al reported the coating of a nanostructured titanium implant with zinc oxide nanoparticles [61]. The nanostructured surface of titanium implants has greatly improved osteoblast adhesion and osteointegration, however, it is also known to have enhanced bacterial attachment and biofilm formation.…”