RAPID: Defect-Chemistry Design of Titanium Dioxide for Enhanced Virucidal Photodynamic Properties

非技术描述：本研究项目的目标是开发合成和加工路线，以优化钛基纳米颗粒灭活SARS-CoV-2代冠状病毒的功效。通过一种新的流动合成加工路线和随后的热退火，调整了二氧化钛颗粒的化学和化学计量学，使材料在电磁波谱的可见光范围内具有光活性。这种光激活导致活性氧的产生，这被认为是这种氧化物材料抗病毒活性的核心。能够控制和优化材料（如二氧化钛）的抗病毒活性，可以很容易地涂覆到表面或集成到纤维中，可以对抗菌涂层和个人防护装备（PPE）的生产产生直接和直接的影响。因此，研究成果将主动用于研究和开发COVID-19大流行PPE材料的小组。参与研究的研究生由团队指导进行高度跨学科和社会相关的研究活动，涵盖材料研究，光化学，病毒学和材料制造。技术细节：这项研究计划旨在发展基础科学，将二氧化钛的化学成分与其抗病毒特性联系起来。这项研究的动机是迫切需要开发能够灭活COVID-19病毒的涂料和个人防护装备（PPE）。在本研究中，通过具有原位诊断的微尺度流动合成平台实现了二氧化钛纳米颗粒的精确合成。高通量实验平台使研究团队能够系统地研究粒径、相、掺杂浓度等重要变量对二氧化钛光吸收和光动力性能的影响。研究中的一个重要变量是氧化学计量，它是通过低分压氧退火系统控制的。还原反应在二氧化钛晶格中诱导氧空位，从而降低了材料的光学带隙。然而，对活性氧产生的影响，这对抗病毒效果至关重要，以前还没有确定。因此，本研究测量了纳米粒子化学计量学对可见光照射下超氧化物、单线态氧、过氧化氢和羟基自由基等单个活性氧生成的影响。最后，评估了SARS-CoV-2代冠状病毒灭活的功效，从而为这种重要的抗菌光动力材料建立了完整的合成-结构-性能-功能关系。此外，该研究还将最有效材料的知识和加工条件转化为生产应对新冠病毒危机的抗病毒材料的团体。参与的研究生参与了这项高度跨学科的研究活动的各个方面，这为他们在材料设计过程中提供了独特的经验，同时为遏制COVID-19病毒的实际解决方案做出了贡献。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL DESCRIPTION: The goal of this research project is to develop synthesis and processing routes to optimize the efficacy of titania-based nanoparticles for inactivating SARS-CoV-2 surrogate coronaviruses. The chemistry and stoichiometry of titania particles are tuned through a novel flow-synthesis processing route and subsequent thermal annealing to make the material photoactive in the visible-light range of the electromagnetic spectrum. Such light activation leads to the production of reactive oxygen species, which are believed to be central to the antiviral activity of such oxide materials. Being able to control and optimize the antiviral activity of materials such as titania, which can easily be coated onto surfaces or integrated into fibers, can have direct and immediate impact on the production of antimicrobial coatings and personal protective equipment (PPE). As such, the research results are proactively directed towards groups researching and developing PPE materials for the COVID-19 pandemic. The graduate students involved in the research are team-mentored in a highly interdisciplinary and societally relevant research activity that spans materials research, photochemistry, virology, and materials manufacturing.TECHNICAL DETAILS: This research program aims to develop the fundamental science linking the chemistry of titanium dioxide, or titania, to its antiviral properties. The research is motivated by the urgent need to develop coatings and personal protective equipment (PPE) that can inactivate the COVID-19 virus. In this research, precise synthesis of titania nanoparticles is achieved via a micro-scale flow synthesis platform with in situ diagnostics. The high-throughput experimental platform enables the research team to study systematically the important variables of particle size, phase, and doping concentrations on the light absorption and photodynamic properties of titania. An important variable in the study is oxygen stoichiometry, which is systematically controlled through low-partial-pressure oxygen annealing. The reduction reaction induces oxygen vacancies into the titania lattice, which, in turn, lower the optical band gap of the material. The consequences for reactive oxygen species generation, which are critical for antiviral efficacy, have not, however, previously been established. Therefore, this research measures the effects of nanoparticle stoichiometry on the generation of individual reactive oxygen species: superoxide, singlet oxygen, hydrogen peroxide and hydroxyl radicals under visible light illumination. Finally, the efficacy for inactivating SARS-CoV-2 surrogate coronaviruses is assessed, allowing for the development of full synthesis-structure-property-function relationships for this important antimicrobial photodynamic material. Moreover, the research translates the knowledge and processing conditions of the most efficacious materials to groups producing antiviral materials for the COVID-19 crisis. The participating graduate students are involved in all aspects of this highly interdisciplinary research activity, which provides them unique experience in the material design process, while contributing to practical solutions for the containment of the COVID-19 virus.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.