Adhesion and Resuspension of Biological Particulate Matter in Early-Childhood Indoor Microenvironments

婴幼儿90%以上的时间在室内度过，因此暴露在室内环境中的许多制剂中。房屋灰尘富含令人难以置信的各种微生物和过敏原。早年吸入室内粉尘中的微生物和致敏物质，在哮喘和过敏性疾病的发病和预防中都发挥着重要作用。当婴儿爬行、玩耍和学习走路时，他们会从尘埃中激起(重新悬浮)浓缩的生物微粒物质云(生物微粒：细菌、真菌、花粉)。室内生物可吸入颗粒物的再悬浮和粘附性仍不是很好。需要新的研究来揭示在人类免疫学发展的这一关键时期管理生物PM暴露的潜在运输机制。该项目的目标是明确阐明儿童早期微环境中生物PM的黏附、再悬浮和空气传输的基本机制。将使用一种新型机器人来确定暴露情况，该新型机器人旨在模拟婴儿在室内环境中的运动和暴露在生物PM中。这项研究有可能改变我们对婴儿在发育的关键阶段暴露于生物PM的理解。通过一个机械框架，该项目将对从根本上理解复杂的附着和人类驱动的再悬浮过程做出实质性贡献，这些过程控制着室内环境中尘埃落定的生物PM的排放、空气传输和命运。具体目标是：1)通过原子力显微镜研究生物PM与室内表面之间的粘附力相互作用，并探索生物PM的形态、疏水性、电荷和湿度对附着力的影响；2)开发一种新型机器人平台，以根据普渡米勒儿童发展实验学校(MCDLS)收集的生物统计学数据来模拟婴幼儿的运动，并研究空气动力学、振动和静电生物PM的去除力；以及3)通过与机器人的室内实验，了解婴儿/幼儿的运动如何重新悬浮生物PM，并开发物质平衡模型来预测生物PM的命运和运输。这项研究将为生物颗粒的物理化学特性如何影响室内表面的粘附力创造新的知识。将首次确定由婴儿特有的运动形式诱导的生物PM去除机制。该项目将产生大量关于生物微粒附着力和再悬浮分数的经验数据。这项研究的新颖性进一步体现在将儿童保育中心收集的6周至3岁婴儿/幼儿的加速度计数据整合到机器人的设计中，用于气溶胶物理和微生物学的接口研究。最后，本研究将创新性地利用基于树莓PI的低成本颗粒传感器阵列来探索再悬浮生物PM浓度的时空变化，这将为多区域物质平衡模型的发展提供参考。本科生将作为社区服务跨学科工程项目(EPICS)团队的一部分，参与生物PM实验，参与K-12学校关于室内空气质量问题的服务学习项目，并参与基于树莓PI的传感器和机器人的开发。将创建关于生物PM材料平衡建模的新的研究生课程内容。该项目将积极邀请普渡MCDLS教师、家长、看守人员和建筑设施经理参与那些与婴儿及其室内环境直接互动的人员。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Infants and toddlers spend over 90% of their time indoors and are thus exposed to numerous agents in the indoor environment. House dust is heavily enriched with an incredible diversity of microbes and allergens. Early-life inhalation exposures to the microbial and allergenic content of indoor dust can play a significant role in both the development of, and protection against, asthma and allergic diseases. As infants crawl, play, and learn to walk, they stir-up (resuspend) concentrated clouds of biological particulate matter (bioPM: bacteria, fungi, pollen) from settled dust. The resuspension and adhesion of indoor bioPM remains poorly characterized. New research is needed to uncover the underlying transport mechanisms that govern bioPM exposures during this critical period in human immunological development. The goal of this project is to explicitly elucidate the fundamental mechanisms governing the adhesion, resuspension, and airborne transport of bioPM in early-childhood microenvironments. Exposure will be determined using a novel robot designed to simulate the movement of infants in the indoor environment and exposure to bioPM. This research has the potential to transform our understanding of infant exposure to bioPM at a critical stage in their development. Through a mechanistic framework, this project will make substantial contributions towards a fundamental understanding of the complex adhesion and human-driven resuspension processes that control the emissions, airborne transport, and fate of bioPM from settled dust in indoor environments. The specific objectives are: 1) investigate the adhesive interactions between bioPM and indoor surfaces through atomic force microscopy and explore the impact of bioPM morphology, hydrophobicity, charge, and humidity on adhesion forces; 2) develop a novel robotic platform to simulate infant/toddler movements informed by biometric data collected at the Purdue Miller Child Development Laboratory School (MCDLS) and to investigate aerodynamic, vibrational, and electrostatic bioPM removal forces; and 3) discover how infant/toddler movements resuspend bioPM through chamber experiments with the robot and develop a material balance model to predict bioPM fate and transport. This research will create new knowledge on how bioPM physiochemical properties affect adhesion forces to indoor surfaces. For the first time, bioPM removal mechanisms induced by forms of locomotion unique to infants will be determined. This project will generate extensive empirical data on bioPM adhesion forces and resuspension fractions. The novelty of the research is further exemplified by the integration of accelerometry data collected in a childcare center with infants/toddlers from 6 weeks to 3 years of age into the design of a robot for use in research at the interface of aerosol physics and microbiology. Lastly, the study will make innovative use of a Raspberry Pi-based low-cost particle sensor array to explore spatiotemporal variations in concentrations of resuspended bioPM which will infom the development of a multi-zone material balance model. Undergraduate students will participate in the bioPM experiments, in service learning projects on indoor air quality issues in K-12 schools as part of an interdisciplinary Engineering Projects in Community Service (EPICS) team, and in the development of the Raspberry Pi-based sensors and robot. New graduate course content on bioPM material balance modelling will be created. The project will actively involve Purdue MCDLS teachers, parents, custodial staff, and building facility managers to engage those who interact directly with infants and their indoor environments.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.