2023-08-30 ロイヤルメルボルン工科大学(RMIT)
◆微規模な突起模様をチタンのインプラントなどに導入し、薬剤不要で細菌やカビから保護する効果を示しました。特に多剤耐性の致死的なカンジダ菌に対する効果が確認され、細胞の死を引き起こすことで抵抗力の形成を抑制する可能性が示されました。これにより、耐性菌に対する新たなアプローチが開拓される一方で、表面模様の最適化や実用的な応用への展開が今後の課題とされています。
<関連情報>
- https://www.rmit.edu.au/news/all-news/2023/aug/antifungal-titanium
- https://onlinelibrary.wiley.com/doi/full/10.1002/admi.202300314
- https://www.sciencedirect.com/science/article/abs/pii/S2589152918302370
微細構造化チタン表面における多剤耐性カンジダ種のアポトーシス Apoptosis of Multi-Drug Resistant Candida Species on Microstructured Titanium Surfaces
Phuc H. Le, Denver P. Linklater, Arturo Aburto-Medina, Shuai Nie, Nicholas A. Williamson, Russell J. Crawford, Shane Maclaughlin, Elena P. Ivanova
Advanced Materials Interfaces Published: 17 August 2023
DOI:https://doi.org/10.1002/admi.202300314
Abstract
The proportion of hospital-acquired medical device infections caused by pathogenic, multi-drug resistant Candida species occurs in up to 10% of implantations. In this study, a unique antifungal micro-pillared titanium surface pattern is developed, which demonstrates both fungicidal and fungistatic activity, persistently deterring biofilm formation by Candida albicans and multi-drug resistant Candida auris fungi for up to 7 days. The Ti micropillars of 3.5 µm height are fabricated using maskless inductively coupled plasma reactive ion etching. The micro-textured surface consistently kills ≈50% of Candida spp. irreversibly attached cells and prevent the proliferation of the remaining cells by inducing programmed cell death. Proteomic analysis reveals that Candida cells undergo extensive metabolic stress, preventing the transformation from yeast to the filamentous/hyphal cell phenotype that is essential for establishing a typical in vitro biofilm. The mechanical stress imparted following interaction with the micropillars injures attaching cells and induces apoptosis whereby the Candida cells are unable to be revived in a non-stress environment. These findings shed new insight toward the design of durable antifungal surfaces that prevent biofilm formation by pathogenic, multi-drug resistant yeasts.
階層的表面構造を有するチタン基材による黄色ブドウ球菌および緑膿菌の機械的不活性化 Mechanical inactivation of Staphylococcus aureus and Pseudomonas aeruginosa by titanium substrata with hierarchical surface structures
Denver P Linklater, Saulius Juodkazis, Russell J. Crawford, Elena P. Ivanova
Materialia Available online :23 December 2018
DOI:https://doi.org/10.1016/j.mtla.2018.100197
Abstract
Titanium is the material of choice for the manufacture of orthopaedic and dental implants because of excellent corrosion resistance and proven biocompatibility. The occurrence of premature implant failure due to implant-associated infections, however, remains a prominent concern for clinicians. In this work, titanium substrata possessing micron-scale surface architectures were fabricated using a process of mask-less plasma etching of bulk titanium for periods of 5, 10, 20, 30 and 40 minutes. The resultant surfaces were characterised using two-dimensional Fast-Fourier Transforms (2D-FFT), scanning electron microscopy (SEM) and atomic force microscopy (AFM), which highlighted the formation of a two-tier pillared surface topology at the maximum etch period. Each of the substrata were assessed for antibacterial efficiency against two common human pathogens, Pseudomonas aeruginosa and Staphylococcus aureus bacteria, achieving maximum antibacterial efficiencies of 87.2 ± 2% and 72.5 ± 13%, respectively. Significantly, the formation of these three-dimensional (3D) hierarchical features was found to minimise the extent of attachment of S. aureus cells, directionally trapping the cells inside the micron size pillars with the second tier of pillars acting to kill the cells. The results of this work shed new light on the development of smart mechano-bactericidal surfaces based on tuning their micron-scale surface topology and suggest that such complex hierarchical surfaces can be particularly effective towards inactivation of cocci bacteria, such as S. aureus.
