Improved Magnetoelastic (ME) Sensing By Using Gelatin for Salmonella Pick-up from Large Scale Surfaces

Abstract

ME sensing, as a fast, on-site, and label-free measurement technique, has been studied in the recent decade for the detection of Salmonella. During the development of ME sensors, there has been a dilemma – to increase sensitivity, the size of a ME sensor must be reduced, while in direct surface detection, a reduced sensor size results in a smaller detection area, larger edge effect, and is harder to handle. To solve this problem, in this paper we introduce a novel gelatin assisted ME sensing system. A gelatin solution at a concentration of 0.05 g/ml was prepared and uniformly applied to the sample surface. A thin gelatin film formed after 2 hours of drying and was easily peeled off to remove most of the Salmonella colonies from the surface. With the application of gelatin, the detection area of one ME sensor was improved from 0.2 mm x 1 mm to 30 mm x 30 mm. In our previous study, swabbing, as an inexpensive, easy-to-use, and widely accepted sampling method, has been used to improve the ME biosensing system for quick detection of surface pathogens. Compared with the swab sampling method, not only was the recovery rate of gelatin assisted ME sensing system much higher, but the detection limit can be significantly improved.