Introduction O157:H7 is one of the most dangerous foodborne pathogens, infecting an estimated 63,000 people in the US each year, including 20 deaths, and having an infective dose as low as 10 cells [1,2]
Introduction O157:H7 is one of the most dangerous foodborne pathogens, infecting an estimated 63,000 people in the US each year, including 20 deaths, and having an infective dose as low as 10 cells [1,2]. A linear relationship between bacteria concentration and impedance value was obtained between 104 cfumL?1 and 107 cfumL?1. Though impedance measurement was carried out in the presence of a redox probe, analysis of the equivalent circuit model showed that the impedance change was primarily due to two elements: Double layer capacitance and resistance due to electrode surface roughness. The magnetic field and impedance were simulated using COMSOL Multiphysics software. O157:H7, rapid detection 1. Introduction O157:H7 is one of the most dangerous foodborne pathogens, infecting an estimated 63,000 people in the US each year, including 20 deaths, and having an infective dose as low as 10 cells [1,2]. Infection of O157:H7 may cause a life-threatening complication known as hemolytic uremic syndrome in 10%C15% of patients with hemorrhagic colitis. O157:H7 infections have primarily been associated with ground beef and leafy green produce but increased integration of the food supply chain has resulted in O157:H7 contamination of unusual food products, such as cookie dough and hazelnuts . Contaminated food products not only threaten human health but also cost food producers millions of dollars in economic loss . As such, a method to rapidly detect O157:H7 in food products is needed. Bacterial culture and plating and polymerase chain reaction are the traditional methods for O157:H7 detection, but these methods are time-consuming and require trained personnel and specialized Aldicarb sulfone laboratories and equipment. Results Aldicarb sulfone may take days, during which food products may have been shipped to consumers or to other producers. Biosensors have attracted attention in the field of foodborne pathogen detection due to their speed, simplicity, and low cost. Several types of biosensors have been developed for the detection of O157:H7 including quartz crystal microbalance [5,6,7,8], surface plasmon resonance [9,10,11,12] and electrochemistry [13,14,15,16,17,18,19,20,21]. Many of the developed biosensors relied on immobilization of antibodies within the sensing surface to concentrate and hold the bacterial cells close plenty of to the sensing surface for measurement. This method has Aldicarb sulfone the problem of low capture effectiveness, often being as low as 35% actually after extensive optimization . A method not reliant on electrode immobilization should be used to conquer the problem of low capture effectiveness. Magnetic nanoparticles have been used extensively in biosensors for bacterial detection though usually for immunomagnetic separation of the bacteria from a sample [13,14,15] or as labels to increase the sensitivity of the biosensor [7,8]. Magnetic nanoparticles may also be used to concentrate the bacterial cells onto the sensing surface, as carried out by Varshney and Li , where a magnetic field was applied under the electrode to pull the bacteria close to an interdigitated microelectrode array for sensitive detection. The interdigitated microelectrode arrays used by Varshney and Li , while being highly sensitive, were time-consuming and expensive to produce, making them impractical for commercial use. Screen imprinted interdigitated electrodes are capable of being produced at a much lower cost and in high volume, making them practical for use in Rabbit polyclonal to Hemeoxygenase1 commercialized quick tests. Recently, a screen imprinted interdigitated electrode was successfully used for the development of an impedance biosensor for detection of avian influenza (AI) disease , but this reported biosensor required transmission amplification with labels. The impedance immunosensor developed in this study was a label-free detection approach. In addition, the size of AI virus is definitely 80C120 nm in diameter, whereas an O157:H7 cell is about 1C1.5 m long and 0.5 m (or 500 nm) in diameter, and there are several variations in biological components; e.g. physical structure and binding sites, between AI disease and bacterial cells. Consequently, we have attempted to explore a new software of the display imprinted interdigitated electrode centered impedance immunosensor for bacteria detection. Aldicarb sulfone In this study, an impedance immunosensor for the detection of O157:H7 was developed using antibody-coated magnetic nanobeads and display imprinted interdigitated electrodes. In the research the antibody-coated magnetic nanobeads served three tasks: (1) to specifically independent O157:H7 cells from press and place them in redox probe for measurement; (2) to concentrate the separated O157:H7 into.