Robust manufacturable antimicrobial surfaces enabled by superhard plasmon-enhanced photocatalytic materials

无法治愈的感染是现代社会最大的危险之一，目前的SARS-CoV-2大流行突显了这一点。抗生素的发展是过去100年来的主要医学成就之一。然而，病原体进化并对新抗生素产生抗药性的能力使得它们的有效性必然不稳定。与此同时，对耐甲氧西林金黄色葡萄球菌、呼吸道合胞病毒、诺沃克病毒和新冠肺炎等耐药病原体传播的研究表明，表面是一个主要的传播点，新冠肺炎在塑料和不锈钢表面上会保持感染长达6天。具有抗菌功能的表面可以避免或最大限度地减少抗生素的使用，同时在长期使用后保持良好的效果，这在医院、生活空间和生物医学植入物上是至关重要的，以减少医疗保健获得性和公共场所获得性感染，降低医疗成本，并促进更健康的生活。然而，标准的抗菌表面不够坚固，不足以承受在生物医学植入环境和公共场所遇到的磨损。谢菲尔德哈勒姆大学和伦敦帝国理工学院的目标是开发具有等离子体增强光催化的超硬纳米结构表面，这将使微生物在光照和黑暗环境中都能失活，同时长期保持其健壮性和有效性，因此，这将导致骨科植入物和抗菌表面比目前技术生产的更具功能性。由于使用了磨损率高达传统金属合金1000倍的超硬纳米多层涂层，创新的抗菌表面将更加坚固。同时，坚固的抗菌表面将具有双重功能--(1)活性，它们将能够通过光催化产生高活性的单线态氧来杀灭微生物--单线态氧是最有效的病原体杀手之一。光催化将被来自环境的可见光激活。光将与精心准备的涂层材料相互作用，在其表面诱导等离子体共振，并产生高能电子，这是促进光催化反应所需的。(2)被动的，模仿自然产生的表面，如蝉的翅膀，表面将包含一些尺寸适当的纳米管，这些纳米管将拉伸并机械地破坏微生物的壁。我们开发了一种新型的等离子体纳米多层膜材料，可以在标准(可见光)光下激活光催化作用，并开发了基于高功率脉冲磁控溅射的技术，可以在室温下在聚合物上制备这些材料。我们将研究生产材料和纳米细菌所需的等离子体过程，它们对光激活的反应，以及它们对微生物的影响。这将有助于我们开发具有成本效益的制造技术，通过升级工业上已有的涂层沉积和纳米加工系统，实现大规模生产，并使用由人工智能算法驱动的数字化系统控制。我们将与当地NHS医院信托基金一起，在门家具的金属板和覆盖医院表面(病床、休息区)的聚合物板材上试验这种材料。一旦成功，我们将在坚固的抗菌材料及其制造方面取得一些最令人兴奋的新进展，并向完全有效的感染控制世界更近一步。

Untreatable infections are one of the biggest modern-day dangers to society, which the current SARS-CoV-2 pandemic has highlighted. The development of antibiotics has been one of the major medical successes of the last 100 years. However, the capacity of pathogens to evolve and acquire resistance to new antibiotics makes their effectiveness necessarily precarious. Meanwhile, studies on the spread of drug-resistant pathogens such as MRSA, respiratory syncytial virus, norovirus and CoVID-19 suggest that surfaces are a major point of transmission with CoVID-19 remaining infectious on plastic and stainless steel surfaces for up to 6 days. Surfaces with an antimicrobial function that avoid or minimise the use of antibiotics whilst maintaining good efficacy after prolonged use are critically needed in hospitals, living spaces, and on biomedical implants, to reduce healthcare-acquired and public space-acquired infections, reduce healthcare costs, and promote healthier lives. However standard antimicrobial surfaces are not sufficiently robust to withstand the wear and tear encountered in a biomedical implant environment and in public spaces. Sheffield Hallam University and Imperial College London aim to develop superhard nanostructured surfaces with plasmonically-enhanced photocatalysis which will enable microbial inactivation in both illuminated and dark environments whilst retaining their robustness and effectiveness in the long term and which, as a result, will lead to orthopaedic implants and anti-microbial surfaces that are more functional than those produced with the current technologies. The innovative antimicrobial surfaces will be robust due to the use of superhard nanoscale multilayer coatings with wear rates up to 1000 times better than conventional metal alloys. At the same time the robust antimicrobial surfaces will have a dual functionality - (1) active, they will be able to kill microorganisms by photocatalysing the production of highly reactive singlet oxygen - one of the most effective killers of pathogens. The photocatalysis will be activated by visible light from the environment. The light will interact with a carefully prepared coating material to induce plasmonic resonance on its surface and generate high energy electrons which are needed to boost the photocatalytic reaction. (2) passive, mimicking naturally occurring surfaces such as the cicada wing, the surfaces will contain a number of appropriately dimensioned nanopillars which will stretch and mechanically rupture the walls of microorganisms. This functionality is potent in wet, dry, illuminated or dark environments.We have developed a new plasmonic nanoscale multilayer material which activates photocatalysis under standard (visible) light and have developed technology based on high power impulse magnetron sputtering which can produce these materials at room temperature on polymers. We will study the plasma processes needed to produce the materials and nanopillars, their response to light activation and the effect they have on microbials. This will help us to develop a cost-effective manufacturing technology to enable large scale production by upgrading systems which are already available in industry for coating deposition and nanopatterning with a digitalised system control which is driven by artificial intelligence algorithms. Together with the local NHS hospital trust we will trial the material on metal plates for door furniture and polymer sheets to cover surfaces in hospitals (beds, seating areas). When successful we will have some of the most exciting new developments in robust antimicrobial materials and their manufacturing and take a step closer to a world with fully effective infection control.