Nanotechnology-Based Environmental Smart Sensors for Personal Health Exposure Monitoring

 描述(由申请人提供)：拟议研究的一个广泛目标是开发个人暴露监测仪，包括可穿戴的无线传感器阵列，以检测呼吸区内的有害空气污染物，并改进流行病学研究中对致因性暴露-剂量-反应关系的评估。由功能化碳纳米管(CNT)谐振器组成的异质正交探测器将设计并与智能手机平台集成，目标是检测第一阶段的环境臭氧(O3)、第二阶段的颗粒物、NOx和VOCs。臭氧不仅通过温室气体排放影响全球气候变化，而且通过交通和工业污染产生的前体，作为城市雾霾中的二次污染物，对人类健康产生不利影响。作为一种强大的氧化剂气体，臭氧一旦吸入就会引发一系列生理反应，包括肺功能下降和呼吸道发炎，加剧哮喘等呼吸道疾病。许多研究工作解决了臭氧暴露与健康结果之间的关系，包括死亡率和发病率(住院、肺功能下降和哮喘状况)，但由于缺乏个人暴露数据，在评估剂量-反应关系方面可能会引入相当大的误差。目前，市场上还没有适用于呼吸区内臭氧暴露实时测量的传感器。第一阶段研究开发臭氧暴露探测器阵列，使用两类纳米传感器制造：(A)聚丁二烯聚合物功能化碳纳米管薄膜，(B)用铂或钯金属纳米颗粒装饰的碳纳米管薄膜。两者对臭氧的敏感度最高，同时降低了对NOx等干扰物的交叉敏感度。这些探测器薄膜与紧凑的射频(RF)谐振器集成在一起，这些谐振器通过分子水平的气体吸附在薄膜界面上引起独特的共振位移来响应。与化学电阻不同的是，这种射频纳米传感器中的幅度和频率偏移都可以用来最大限度地减少假阳性，从而实现稳健的区分。初级传感器和参考传感器(纯碳纳米管)之间的差异信号补偿了湿度等环境因素，进一步提高了选择性。差动信号通过微控制器和智能电话无线连接，用于显示浓度水平的数据，并通过参与性和无处不在的传感向公共卫生专业人员或监管机构进行数据通信。此外，嵌入在移动电话中的传感器可以提供与曝光相关的对象的运动、身体活动、时间戳和GPS位置的信息。将开发一个原型臭氧传感器，并在受控的实验室和环境条件下表征其性能。将在人类志愿者身上进行现场测试，以检测几天内环境臭氧随时间的变化，并将结果直接与标准徽章采样器的测量结果进行比较。将与环境流行病学家合作，通过在暴露后测量eNO浓度来探索因果关系。

 DESCRIPTION (provided by applicant): A broad goal of the proposed research is to develop personal exposure monitors comprising wearable, wireless sensor arrays to detect harmful air pollutants within the breathing zone, and improve the assessment of causative exposure-dose-response relationships in epidemiological studies. Heterogeneous orthogonal detectors comprising functionalized carbon nanotube (CNT) based resonators will be designed and integrated with a smart phone platform, targeting the detection of ambient ozone (O3) in Phase 1, particulate matter, NOx and VOCs in Phase 2. Ozone not only influences climatic changes globally through greenhouse gas emissions, but also produces adverse health effects in humans as a secondary pollutant in urban smog through precursors generated in traffic and industrial pollution. As a powerful oxidant gas, O3 can elicit a range of physiological responses once inhaled, including reduced lung function and inflamed airways, exacerbating respiratory diseases such as asthma. Numerous research efforts address the relationship between ozone exposure and health outcomes including mortality and morbidity (hospitalizations, decrements in lung function, and asthma status), but due to lack of personal exposure data, considerable error may be introduced in assessing dose-response relationships. Currently, there are no existing sensors in the market suitable for real- time O3 exposure measurement within the breathing zone. Phase 1 research develops an ozone exposure detector array, fabricated using two classes of nanosensors: (a) polybutadiene polymer-functionalized CNT thin-films, (b) CNT thin-films decorated with Pt or Pd metallic nanoparticles. Both offer maximum sensitivity to ozone while reducing cross-sensitivity to interferents such as NOx. These detector films are integrated with compact radio-frequency (RF) resonators, which respond with unique resonance shift caused by molecular level gas adsorption on the film interface. In contrast to a chemiresistor, both amplitude and frequency shifts in this RF nanosensor may be used to minimize false positives for robust discrimination. Differential signaling between the primary sensor and a reference sensor (pure CNTs) compensates for environmental factors such as humidity, further improving selectivity. The differential signal is wirelessly interfaced through a microcontroller t a smart phone for data display of concentration levels and data communication to public health professionals or regulatory bodies via participatory and ubiquitous sensing. Additionally, sensors embedded in the mobile phone yield information on motion, physical activity, time stamp and GPS location of the subject that can be correlated to the exposure. A prototype O3 sensor will be developed and its performance characterized under controlled laboratory and ambient conditions. Field tests will be conducted on human volunteers to detect ambient ozone as a function of time over several days, and results compared directly with measurements made by standard badge samplers. Causative relationships will be explored by measuring eNO concentrations following the exposure, in collaboration with an environmental epidemiologist.