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

非技术描述：该研究项目的目标是开发合成和加工路线，以优化基于二氧化钛的纳米颗粒灭活SARS-CoV-2替代冠状病毒的功效。二氧化钛颗粒的化学和化学计量通过一种新的流动合成工艺路线和随后的热退火进行调整，使材料在电磁光谱的可见光范围内具有光活性。这种光活化导致活性氧物质的产生，据信活性氧物质是这种氧化物材料的抗病毒活性的核心。能够控制和优化二氧化钛等材料的抗病毒活性，这些材料可以很容易地涂覆到表面上或集成到纤维中，可以对抗菌涂料和个人防护设备（PPE）的生产产生直接和直接的影响。因此，研究结果积极针对研究及开发针对COVID-19疫情的个人防护装备材料的团体。参与研究的研究生将在一个高度跨学科和社会相关的研究活动中进行团队指导，该研究活动涵盖材料研究，光化学，病毒学和材料制造。技术支持：该研究计划旨在发展将二氧化钛或二氧化钛的化学性质与其抗病毒特性联系起来的基础科学。这项研究的动机是迫切需要开发能够抵抗COVID-19病毒的涂层和个人防护设备（PPE）。 在这项研究中，精确的二氧化钛纳米粒子的合成是通过一个微尺度的流动合成平台与原位诊断。高通量实验平台使研究团队能够系统地研究粒径，相和掺杂浓度对二氧化钛光吸收和光动力学性质的重要变量。研究中的一个重要变量是氧的化学计量，这是通过低分压氧退火系统控制。还原反应将氧空位引入到二氧化钛晶格中，这反过来又降低了材料的光学带隙。然而，对于抗病毒功效至关重要的活性氧产生的后果先前尚未确定。因此，本研究测量纳米颗粒化学计量对单个活性氧物种的产生的影响：超氧化物，单线态氧，过氧化氢和羟基自由基在可见光照射下。最后，对灭活SARS-CoV-2替代冠状病毒的功效进行了评估，从而为这种重要的抗微生物光动力材料的完整合成-结构-性质-功能关系的发展奠定了基础。此外，该研究将最有效材料的知识和加工条件转化为生产COVID-19危机抗病毒材料的团体。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，这为他们提供了材料设计过程中的独特经验，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NSF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.