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Morel J, McNeilly O, Grundy S, Brown T, Gunawan C, Amal R, Scott JA. Nanoscale Titanium Surface Engineering via Low-Temperature Hydrothermal Etching for Enhanced Antimicrobial Properties. ACS APPLIED MATERIALS & INTERFACES 2023; 15:46247-46260. [PMID: 37738302 DOI: 10.1021/acsami.3c09525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/24/2023]
Abstract
Bioinspired nanotopography artificially fabricated on titanium surfaces offers a solution for the rising issue of postoperative infections within orthopedics. On a small scale, hydrothermal etching has proven to deliver an effective antimicrobial nanospike surface. However, translation to an industrial setting is limited by the elevated synthesis temperature (150 °C) and associated equipment requirements. Here, for the first time, we fabricate surface nanostructures using comparatively milder synthesis temperatures (75 °C), which deliver physicochemical properties and antimicrobial capability comparable to the high-temperature surface. Using a KOH etchant, the simultaneous formation of titania and titanate crystals at both temperatures produces a one-dimensional nanostructure array. Analysis indicated that the formation mechanism comprises dissolution and reprecipitation processes, identifying the deposited titanates as hydrated layered tetra-titanates (K2Ti4O9·nH2O). A proposed nanospike formation mechanism was confirmed through the identification of a core and outer shell for individual nanostructures, primarily comprised of titanates and titania, respectively. Etching conditions dictated crystalline formation, favoring a thicker titanate core for nanorods under higher synthesis temperatures and etchant concentrations. A bactericidal investigation showed the efficacy against Gram-negative bacteria for a representative low-temperature nanosurface (34.4 ± 14.4%) was comparable to the higher temperature nanosurface (34.0 ± 17.0%), illustrating the potential of low-temperature hydrothermal synthesis. Our results provide valuable insight into the applicability of low-temperature etching protocols that are more favorable in large-scale manufacturing settings.
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Affiliation(s)
- James Morel
- School of Chemical Engineering, University of New South Wales, Kensington, NSW 2052, Australia
| | - Oliver McNeilly
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Broadway, NSW 2007, Australia
| | - Sarah Grundy
- School of Chemical Engineering, University of New South Wales, Kensington, NSW 2052, Australia
| | - Toby Brown
- Corin Australia, Pymble, NSW 2073, Australia
| | - Cindy Gunawan
- Australian Institute for Microbiology and Infection, University of Technology Sydney, Broadway, NSW 2007, Australia
| | - Rose Amal
- School of Chemical Engineering, University of New South Wales, Kensington, NSW 2052, Australia
| | - Jason A Scott
- School of Chemical Engineering, University of New South Wales, Kensington, NSW 2052, Australia
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Bright R, Hayles A, Wood J, Palms D, Barker D, Vasilev K. Interplay between Immune and Bacterial Cells on a Biomimetic Nanostructured Surface: A "Race for the Surface" Study. ACS APPLIED BIO MATERIALS 2023; 6:3472-3483. [PMID: 37384836 DOI: 10.1021/acsabm.3c00351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
Biomaterial-associated infection is an ever-increasing risk with devasting consequences for patients. Considerable research has been undertaken to address this issue by imparting antibacterial properties to the surface of biomedical implants. One approach that generated much interest over recent years was the generation of bioinspired bactericidal nanostructures. In the present report, we have investigated the interplay between macrophages and bacteria on antibacterial nanostructured surfaces to determine the outcome of the so-called "race for the surface". Our results showed that macrophages can indeed outcompete Staphylococcus aureus via multiple mechanisms. The early generation of reactive oxygen species by macrophages, downregulation of bacterial virulence gene expression, and the bactericidal nature of the nanostructured surface itself collectively acted to help the macrophage to win the race. This study highlights the potential of nanostructured surfaces to reduce infection rates and improve the long-term success of biomedical implants. This work can also serve as guidance to others to investigate in vitro host-bacteria interactions on other candidate antibacterial surfaces.
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Affiliation(s)
- Richard Bright
- College of Medicine and Public Health, Flinders University, Bedford Park, SA 5042, Australia
| | - Andrew Hayles
- College of Medicine and Public Health, Flinders University, Bedford Park, SA 5042, Australia
| | - Jonathan Wood
- Academic Unit of STEM, University of South Australia, Mawson Lakes, Adelaide, SA 5095, Australia
| | - Dennis Palms
- College of Medicine and Public Health, Flinders University, Bedford Park, SA 5042, Australia
| | - Dan Barker
- Corin Australia, Sydney, NSW 2153, Australia
| | - Krasimir Vasilev
- College of Medicine and Public Health, Flinders University, Bedford Park, SA 5042, Australia
- Academic Unit of STEM, University of South Australia, Mawson Lakes, Adelaide, SA 5095, Australia
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Senevirathne SWAI, Mathew A, Toh YC, Yarlagadda PKDV. Bactericidal Efficacy of Nanostructured Surfaces Increases under Flow Conditions. ACS OMEGA 2022; 7:41711-41722. [PMID: 36406483 PMCID: PMC9670296 DOI: 10.1021/acsomega.2c05828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
Bacterial colonization on solid surfaces creates enormous problems across various industries causing billions of dollars' worth of economic damages and costing human lives. Biomimicking nanostructured surfaces have demonstrated a promising future in mitigating bacterial colonization and related issues. The importance of this non-chemical method has been elevated due to bacterial evolvement into antibiotic and antiseptic-resistant strains. However, bacterial attachment and viability on nanostructured surfaces under fluid flow conditions has not been investigated thoroughly. In this study, attachment and viability of Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus) on a model nanostructured surface were studied under fluid flow conditions. A wide range of flow rates resulting in a broad spectrum of fluid wall shear stress on a nanostructured surface representing various application conditions were experimentally investigated. The bacterial suspension was pumped through a custom-designed microfluidic device (MFD) that contains a sterile Ti-6Al-4V substrate. The surface of the titanium substrate was modified using a hydrothermal synthesis process to fabricate the nanowire structure on the surface. The results of the current study show that the fluid flow significantly reduces bacterial adhesion onto nanostructured surfaces and significantly reduces the viability of adherent cells. Interestingly, the bactericidal efficacy of the nanostructured surface was increased under the flow by ∼1.5-fold against P. aeruginosa and ∼3-fold against S. aureus under static conditions. The bactericidal efficacy had no dependency on the fluid wall shear stress level. However, trends in the dead-cell count with the fluid wall shear were slightly different between the two species. These findings will be highly useful in developing and optimizing nanostructures in the laboratory as well as translating them into successful industrial applications. These findings may be used to develop antibacterial surfaces on biomedical equipment such as catheters and vascular stents or industrial applications such as ship hulls and pipelines where bacterial colonization is a great challenge.
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Affiliation(s)
- S. W.
M. A. Ishantha Senevirathne
- Centre
for Biomedical Technologies, Queensland
University of Technology, Brisbane, QLD4000, Australia
- School
of Mechanical, Medical, and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD4000, Australia
| | - Asha Mathew
- Centre
for Biomedical Technologies, Queensland
University of Technology, Brisbane, QLD4000, Australia
- School
of Mechanical, Medical, and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD4000, Australia
| | - Yi-Chin Toh
- Centre
for Biomedical Technologies, Queensland
University of Technology, Brisbane, QLD4000, Australia
- School
of Mechanical, Medical, and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD4000, Australia
| | - Prasad K. D. V. Yarlagadda
- Centre
for Biomedical Technologies, Queensland
University of Technology, Brisbane, QLD4000, Australia
- School
of Mechanical, Medical, and Process Engineering, Faculty of Engineering, Queensland University of Technology, Brisbane, QLD4000, Australia
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