"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.
