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ARS Home » Pacific West Area » Albany, California » Western Regional Research Center » Foodborne Toxin Detection and Prevention Research » Research » Publications at this Location » Publication #321557

Title: Low cost charged-coupled device (CCD) based detectors for Shiga toxins activity analysis

item Rasooly, Reuven
item PRICKRIL, BEN - National Institutes Of Health (NIH)
item BRUCK, HUGH - University Of Maryland
item RASOOLY, AVRAHAM - National Institutes Of Health (NIH)

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 1/26/2017
Publication Date: 3/10/2017
Citation: Rasooly R., Prickril B., Bruck H.A., Rasooly A. 2017. Low-cost charged-coupled device (CCD) based detectors for Shiga toxins activity analysis. In: Rasooly A., Prickril B., editors. Biosensors and Biodetection. Methods in Molecular Biology. Volume 1571. New York, NY: Humana Press. p. 233-249. doi: 10.1007/978-1-4939-6848-0 15

Interpretive Summary: In recent years, charged-coupled devices (CCDs) 1-9 or complementary metal–oxide–semiconductors (CMOSs) 10-13 are increasingly utilized as optical detectors because of their low cost, small size, sensitivity, and low power consumption. Their ability to image large surfaces makes them ideal for sample detection, because many samples can be imaged and analyzed simultaneously. The cost of technical and scientific-grade CCD and CMOS imagers for biodetection is typically high. While webcams, digital cameras, digital imagers for amateur astronomy, and other consumer electronics incorporating imaging components are more affordable, there is a need for low-cost alternatives providing sufficient sensitivity and imaging quality for biodetection at significantly lower cost. This is especially important for Point-of-Care (POC) diagnostics for global health, where it is desirable to enhance the quality of health care delivery at very low cost for underserved populations.

Technical Abstract: To improve food safety there is a need to develop simple, low-cost sensitive devices for detection of foodborne pathogens and their toxins. We describe a simple and relatively low-cost webcam-based detector which can be used for various optical detection modalities, including fluorescence, chemiluminescence, densitometry, and colorimetric assays. The portable battery-operated CCD-based detection system consists of four modules: (1) a webcam to measure and record light emission, (2) a sample plate to perform assays, (3) a Light Emitting Diode (LED) for illumination, and (4) a portable computer to acquire and analyze images. To demonstrate the technology, we used a cell based assay for fluorescence detection of the activity of the food borne Shiga toxin type 2 (Stx2), differentiating between biologically active toxin and inactive toxin which is not a risk. The assay is based on Shiga toxin inhibition of cell protein synthesis measured through inhibition of the green fluorescent protein (GFP). In this assay, GFP emits light at 509 nm when excited with a blue LED equipped with a filter at 486nm. The emitted light is then detected with a green filter at 535 nm. Toxin activity is measured through a reduction in 509 nm emission. In this system the level of detection (LOD) for Stx2 was 0.1 pg/ml similar to the LOD of commercial fluorometers. These results demonstrate the utility and the potential of low cost detectors for toxin activity; this approach could be readily adapted to the detection of other food-borne toxins