Bacteria Death and Osteoblast Metabolic Activity Correlated to Hydrothermally Synthesised TiO2 Surface Properties

Abstract

Orthopaedic surgery comes with an inherent risk of bacterial infection, prolonged antibiotic therapy and revision surgery. Recent research has focused on nanostructured surfaces to improve the bactericidal and osseointegrational properties of implants. However, an understanding of the mechanical properties of bactericidal materials is lacking. In this work, the surface properties of hydrothermal TiO2 nanostructured surfaces are investigated for their effect on bactericidal efficiency and cellular metabolic activity of human osteoblast cells. TiO2 nanostructures, approximately 307 nm in height and 14 GPa stiffness, were the most effective structures against both gram-positive (Staphylococcus aureus) and gram-negative (Pseudomonas aeruginosa) bacteria. Statistical analysis significantly correlated structure height to the death of both bacteria strains. In addition, the surface contact angle and Young’s modulus were correlated to osteoblast metabolic activity. Hydrophilic surfaces with a contact angle between 35 and 50° produced the highest cellular metabolic activity rates after 24 hours of incubation. The mechanical tests showed that nanostructures retain their mechanical stability and integrity over a long time-period, reaffirming the surfaces’ applicability for implants. This work provides a thorough examination of the surface, mechanical and wettability properties of multifunctional hydrothermally synthesised nanostructured materials, capable of killing bacteria whilst improving osteoblast metabolic rates, leading to improved osseointegration and antibacterial properties of orthopaedic implants.

Adaptations and Lessons from COVID-19: A Perspective on How some Industries will be Impacted

“…We have recently shown that surfaces with nanoscale topography can significantly reduce respiratory syncytial virus and rhinovirus [77]. We have also shown that a range of nanostructured surfaces such as titanium and aluminium kill bacterial cells [78][79][80][81][82][83][84]. It is believed that such nanoscale surfaces will also be able to inactivate the SARS-CoV-2.…”

Researcher of the Year 2020-To Recognize the Significant Efforts for COVID-19

“…Later, a thorough examination of the surface, mechanical and wettability properties of multifunctional hydrothermally synthesised nanostructured materials were found to be capable of killing bacteria whilst improving osteoblast metabolic rates, leading to improved osseointegration and antibacterial properties of orthopaedic implants (Fig. 4(C)) [3]. Further to this, the mechanical properties, surface morphology, and stability of the TiO2 surface as a function of NaOH concentration were observed.…”

“…Nano-pillared titanium [1][2][3][4] substrates have been fabricated using hydrothermal processing. The surface architecture has been selectively modulated using the fabrication processing parameters such as temperature, reaction time, and reactant molarity.…”

Bactericidal efficiency of micro- and nanostructured surfaces: a critical perspective

“…However, micro/ nano-topography of the surfaces of MNSS have shown to be most critical in determining the BE. 26,31,33,36,39,[44][45][46][47] In addition, BE has been reported to be inuenced by a number of other parameters such as the type of medium used for bacterial cell incubation, 48 bacterial inoculum concentration, 49,50 incubation time, 39,45,51,52 strain of bacteria. 26,45,53 Despite the popular belief that micro/nanoscale topographies are more effective against Gram-negative strains, numerous studies have also reported higher or equivalent BE of MNSS against Gram-positive strains.…”

“…26,45,53 Despite the popular belief that micro/nanoscale topographies are more effective against Gram-negative strains, numerous studies have also reported higher or equivalent BE of MNSS against Gram-positive strains. 26,[36][37][38][39]51,54 For example, in a study, Jaggessar et al, fabricated six different TiO 2 nanopillars on titanium substrates and studied their bactericidal effect against both Gram-negative (Pseudomonas aeruginosa) and Gram-positive (Staphylococcus aureus) bacteria. 36 All six surfaces tested for bacterial viability, which showed a higher bactericidal rate on Gram-positive than on Gram-negative strains.…”