Novel 3-Dimensional Biosensor for Rapid Detection and Accurate Identification of Salmonella in Food Products

“这项奖励是根据2009年美国复苏和再投资法案（公法111-5）资助的。”目的：研制一种新型的三维交错微电极阵列阻抗生物传感器。这种生物传感器是独特的，在其增加的传感表面积与体积比相比，一个单一的二维交叉微电极传感器。这将提高阻抗检测的灵敏度，以及将几个活细菌细胞限制在纳升量级的体积内的能力，以便快速检测和准确鉴定沙门氏菌。该项目的目标是在简单、轻便、便携和低成本的系统中提供显著改进的检测技术，该系统可以在几分钟内检测出沙门氏菌，具有高选择性和灵敏度。项目目标如下：1)设计制造基于MEMS的阻抗生物传感器系统；2)采用自组装多层法固定抗体；3)与固定抗体结合使用时，利用阻抗测量对花生酱、哈密瓜、芒果和番茄中的沙门氏菌进行检测和选择性鉴定。智力优势：提出的设备代表了生物传感器领域的一个转变。传统的二维生物传感器检测需要相对较大的样本量和大量的细胞。基于三维交叉指状微电极阵列的阻抗生物传感器的灵敏度显著提高，可以在小样本量中轻松检测到少量活细胞。提出的设计采用两组三维交错微电极阵列。第一组使用正电介质电泳将沙门氏菌转移并集中到另一个更窄的通道中，在那里放置了第二组用于检测沙门氏菌的交叉微电极阵列。与单个二维交叉微电极传感器相比，这种交叉微电极阵列增加了传感表面积与体积比。为了检测单个或几个细菌细胞，该阵列装置将被设计成具有接近细菌大小的交叉电极之间的空间。这将使未来一代更小、更轻、更便宜的阻抗生物传感器能够快速检测沙门氏菌。更广泛的影响：这项研究将有利于美国在生物传感器技术方面的竞争力，教育下一代科学家/工程师，并通过保护人类健康、食品和水供应以及防止产品召回来影响经济。它将在设计和理解三维生物传感器方面引入新的基础科学，从而产生低成本的便携式设备。其应用范围包括食品和包装工业、作物保护和生物恐怖主义威胁预防。通过改变生物识别层和器件粘附层，同样的结构可用于检测其他病原体（如大肠杆菌O157:H7、李斯特菌）。研究生和本科生将接受最先进的微纳米和生物技术的教育。PI（密苏里大学）和Co-PI（林肯大学；HBCU）将把研究产生的硬件和软件集成到他们的课程中，使学生能够获得与21世纪科学技术相关的实践经验，并为他们在微电子、生物技术、半导体和微机电系统（MEMS）等不断发展的领域的就业做好准备。学生——包括那些来自代表性不足群体的学生——将参与这个项目，并得到共同的建议。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)."Objectives:A novel 3-dimensional interdigitated microelectrode array based impedance biosensor will be developed. This biosensor is unique in its increased sensing surface area to volume ratio compared to a single 2-dimensional interdigitated microelectrode sensor. This will enhance the sensitivity of impedance detection, and the capability to confine a few live bacterial cells into a volume on the order of nano liters for rapid detection and accurate identification of Salmonella. The project goal is to provide significantly improved detection technology in a simple, lightweight, portable and low-cost system that can detect Salmonella within minutes, with high selectivity and sensitivity. The project objectives are as follows: 1) to design and fabricate MEMS based impedance biosensor system; 2) to immobilize the antibody using the Self-Assembled Multilayer process; 3) to test the device using impedance measurements for the detection and selective identification of Salmonella in peanut butter, cantaloupe, mango and tomato when used in conjunction with immobilized antibodies.Intellectual Merit:The proposed device represents a transformation in the field of biosensors. Detection with conventional 2-dimensional biosensors requires a relatively large sample volume with significantly large number of cells. With 3-dimensional interdigitated microelectrode array based impedance biosensors, the sensitivity is significantly enhanced and a few live cells can be easily detected in a small sample volume. The proposed design uses two sets of 3-dimensional interdigitated microelectrode arrays. The first set uses positive dielectrophoresis to divert and concentrate the Salmonella into another narrower channel where the second set of interdigitated microelectrode arrays-used to detect Salmonella-are located. This interdigitated microelectrode array set increases the sensing surface area to volume ratio compared to a single 2-dimensional interdigitated microelectrode sensor. The array sets will be designed with spaces between the interdigitated electrodes nearly the size of the bacteria in order to detect a single or a few bacteria cells. This will enable a future generation of smaller, lighter, inexpensive impedance biosensors for fast Salmonella detection.Broader Impact: The research will benefit US competitiveness in biosensor technology, educate the next generation of scientists/engineers, and impact the economy though the protection of human health, food and water supplies and prevention of product recalls. It will introduce new basic science in the design and understanding of 3-dimensional biosensors, resulting in a low cost, portable device. The range of applications includes the food and packing industry, protection of crops, and bioterrorism threat prevention. The same structure can be used for detection of other pathogens (e.g., Escherichia coli O157:H7, Listeria) by changing the bio-recognition layer and device adhesion layer. Graduate and undergraduate students will be educated in state-of-the art micro/nano and bio technologies. The PI (University of Missouri) and Co-PI (Lincoln University; HBCU) will integrate the hardware and software generated by the research into their courses, enabling students to receive hands-on experience relevant to 21st century science and technology, and preparing them for employment in the growing fields of microelectronics, biotechnology, semiconductor and microelectromechanical systems (MEMS). Students-including those from underrepresented groups-will work on the project and be co-advised.