Bactericidal nanospike surfaces via thermal oxidation of Ti alloy substrates

Abstract

Highlights Thermal oxidation was used to grow bioinspired nanospikes on Ti alloy. Nanospike dimension and arrangement could be controlled. The method worked on arbitrary shaped Ti alloy surfaces. A 40 % reduction of E. Coli viability was achieved on Ti alloy nanospike surfaces. AbstractWith the aim to fabricate bio-inspired antibacterial nanotopography surfaces, nanospikes with varying dimensions were grown on Ti alloy surfaces using a thermal oxidation method. By controlling the acetone vapour concentration inside the tube furnace, the resulting oxide surface changed from nanocolumn shapes to nanospikes with approximately 20 nm diameters. The nanospikee growth was demonstrated to work on 3D Ti alloy bead surfaces, which means translation of the method to implant surfaces would be possible. Microbiology studies using Escherichia coli. showed that the nanospikes on the Ti alloy surfaces has potential to reduce bacterial viability. More dead bacteria were present on the nanospike surfaces compared to a smooth control and a 40 % reduction of viability was noted in bacterial suspensions incubated with a nanospike surface. It was shown that by annealing the Ti alloy surfaces prior to thermal oxidation, it is possible to grow vertically aligned nanospikes. This could be highly valuable when designing implant surfaces with antimicrobial properties.

Shape-dependent antibacterial effects of non-cytotoxic gold nanoparticles

“…This increase is higher for the AuNFs because their increased surface area may allow them to more readily form complexes with the bacteria. The antibacterial mechanism may have similarities to that observed previously where nanostructured surfaces with a high-aspect ratio, spikes 30 and pillars, 31 induced high local stress on the bacteria membrane inducing membrane rupture. Ultimately, this interaction kills the bacteria, causing a drop in OD, as observed.…”

“…Most research on morphological interactions has been performed on micro-and nano-patterned surfaces, 28,29 where surfaces with a high aspect ratio, spikes or pillars have been shown to reduce bacterial colonization and induce bacterial lysis due to high local stresses on the bacterial cell wall. 30,31 Other physical anti-bacterial methods have recently been shown, based on disrupting the bacterial membrane utilizing magnetic NPs in combination with radiofrequency current or bimetallic NPs, to induce a loss of bacterial membrane potential. 32,33 These strategies, belonging to the emerging field of nanomedicine, show the possibility of ridding humanity of some of its biggest bacterial threats and could help save the lives of millions.…”

Antibacterial effects of nanopillar surfaces are mediated by cell impedance, penetration and induction of oxidative stress

“…The unique bactericidal properties of cicada and dragonfly wings have drawn significant research interest [7][8][9][10] , as the physical nature of bacterial killing could provide an effective strategy to prevent biofilm formation, and infection of indwelling and implantable devices, while negating the current need to use materials impregnated with antibiotics. To date, a wide range of nanofabrication techniques have been utilised to generate bactericidal nanotopographies on synthetic materials, including black silicon (bSi) 2 , titanium 11 , titanium alloy 12 and polymers 13 .…”

Multifunctional Coatings and Nanotopographies: Toward Cell Instructive and Antibacterial Implants

“…Inspired by nature, a number of studies have since been carried out to develop bactericidal nanotopographies on synthetic materials. They include silicon and diamond coated silicon, titanium and its alloy, polymers, stainless steel, and aluminium . Table 3 lists a summary of biomimetic bactericidal surfaces on various materials currently in development.…”

“…Nanowire surfaces exhibited bactericidal properties against S. aureus and E. coli as well as osteogenesis from bone cells. Similarly, nanowire surfaces were generated on Ti alloy substrates using a controlled thermal oxidation method, which also showed bactericidal and osteogenic properties. Crucially, this method could be applied to porous and complex shaped Ti substrates, which paves the way to develop cell‐instructive nanotopographies for implant applications.…”