Direct detection of Listeria monocytogenes DNA amplification products with quartz crystal microbalances at elevated temperatures

Publication date: Available online 7 January 2020Source: Sensors and Actuators B: ChemicalAuthor(s): Sirirat Wachiralurpan, Kosum Chansiri, Peter A. LieberzeitAbstractCurrent methods for identifying Listeria monocytogenes are both time and labor intensive. However, it is highly desirable to detect it rapidly and reliably to prevent and/or identify contamination of foodstuff. Herein we propose a mass-sensitive sensor operating at elevated temperatures, 50-55 °C, for that purpose. Sensitive and selective detection relies on distinguishing genes of genomic extract of L. monocytogenes. A thiol-modified ssDNA probe designed for virulence phosphatidylcholine-phospholipase C (plcB) immobilized on the Quartz Crystal Microbalance (QCM) serves as the recognition element. This hybridizes with synthetic Loop-mediated isothermal amplification (LAMP) products of target DNA on the active surface sensor. Discernible detection limits of approximately 3 × 10-1 to 3 × 10 °CFU mL-1 of L. monocytogenes DMST 17303 gDNA were achieved. The QCM DNA sensor showed high sensitivity and selectivity for L. monocytogenes (100%) with negligible interference by DNA of other food-borne pathogens, such as Salmonella Paratyphi A (24%), Salmonella Weltevreden (24%), Salmonella Typhi (16%), Shigella boydii (22%), and Shigella flexneri (13%). The temperature covered is in the range of 50 to 55 °C for immobilizing DNA probe and DNA targeted hybridization. Hybridization response times were within ...

Source: Sensors and Actuators B: Chemical - January 11, 2020 Category: Chemistry Source Type: research