SENSORS: A Novel Lateral Field Excited Acoustic Wave Sensor for Chemical and Biological Agents

用于灵敏和选择性检测化学剂和生物剂的传感器正在开发中。传感器结构由一个压电平台组成，该平台涂有一层膜，可以选择性地吸收感兴趣的化学或生物制剂。传感器的灵敏度体现在传感器平台上，该平台由一个受侧向电场激励的石英晶体组成。激励电极与传感表面相对放置，传感膜直接附着在传感器平台上。这种安排与标准石英微天平（QCM）形成对比，后者的传感表面通常涂有一层金膜，它提供了更高的灵敏度和选择性。这种新型的横向场激发（LFE） QCM具有很高的灵敏度，这是由于该传感器可以测量由吸附的化学或生物制剂引起的传感膜的电学和机械性能变化。通过直接在传感膜中进行分子滤波，获得了LFE-QCM传感器的选择性。在这个具体的项目中，设计了LFE-QCM传感器来检测两种特定的化学物质和一种生物制剂。目标化学物质是二甲基磷酸酯（DMMP），一种类似VX和G神经毒剂的化学物质，以及一种与许多其他化学战剂化学性质相似的有机磷农药。这种生物制剂是大肠杆菌O157:H7，它可能出现在食物或供水中。为了实现所需的化学和生物传感器，研究小组正在探索与LFE-QCM平台和传感膜有关的几个问题。这些问题包括LFE-QCM平台的最佳电极几何形状，用于检测水中有机磷酸盐的新型聚合物和二氧化硅膜的开发，以及大肠杆菌抗体与传感表面的偶联。国土安全以及环境和工业健康问题要求必须开发和部署改进的化学和生物传感器。将各种山梨酸选择膜附着在LFE-QCM表面后，将其暴露于化学模拟剂和生物制剂中，以确定其传感性能。预计这些有机磷化学物质和大肠杆菌的研究工作可以扩展到其他重要化学和生物制剂的选择性传感器的开发。此外，通过与现有的GK-12和REU项目相结合，该项目将有助于一些参与研究项目的学生和教师的教育。

Sensors for the sensitive and selective detection of chemical agents and a biological agent are being developed. The sensor structure consists of a piezoelectric platform that is coated with a film that selectively sorbs a chemical or biological agent of interest. The sensitivity of the sensor is embodied in the sensor platform, which consists of a quartz crystal that is excited by a lateral electric field. The exciting electrodes are placed opposite to the sensing surface, and the sensing film is attached directly to the sensor platform. This arrangement is in contrast to the standard quartz microbalance (QCM), where the sensing surface is normally coated with a gold film, and it offers increased sensitivity along with selectivity. The high sensitivity exhibited by this novel lateral-field-excited (LFE) QCM is attributed to the fact that the sensor can measure both electrical and mechanical property changes in the sensing film caused by the sorbed chemical or biological agent. The selectivity of the LFE-QCM sensor is obtained by performing molecular filtering directly in the sensing film. In this specific project the LFE-QCM sensor is being designed to detect two specific chemicals and one biological agent. The target chemicals are dimethyl phosponate (DMMP), which simulates VX and G nerve agents, and an organophosphate pesticide that is chemically similar to many other chemical-warfare agents. The biological agent is E. coli O157:H7, which could appear in food or water supplies. In order to realize the desired chemical and biological sensors, the research team is exploring several issues relating to the LFE-QCM platform and the sensing film. These issues include the optimum electrode geometry in the LFE-QCM platform, the development of novel polymer and silica films for the detection of organophosphates in water, and the coupling of E. coli antibodies to the sensing surface. Homeland security as well as environmental and industrial health concerns dictate that improved chemical and biological sensors must be developed and deployed. After various sorbate-selective films have been attached to the LFE-QCM surface, they will be exposed to the chemical simulants and the biological agent in order to determine the sensing properties. It is anticipated that the proposed work on these organo-phosphorus chemicals and E. coli can be extended to development of selective sensors for other significant chemical and biological agents. In addition, by coupling with existing GK-12 and REU programs, this project will contribute to the education of a number of students and teachers who will participate in the research program.