Abstract
A simple, sensitive and selective colorimetric biosensor for the detection of Staphylococcal enterotoxin B (SEB) was developed using SEB-binding aptamer (SEB2) as recognition element and unmodified gold nanoparticles (AuNPs) as colorimetric probes. The assay is based on color change from red to purple due to conformational change of aptamer in the presence of SEB, and the phenomenon of salt-induced AuNPs aggregation which could be monitored by naked eye or UV–vis spectrometer. Results showed that the AuNPs can effectively differentiate the SEB induced conformational change of the aptamer in the presence of a given high salt concentration. A linear response in the range of 50 μg/mL to 0.5 ng/mL of SEB concentration was obtained. The assay was highly specific to SEB as compared to other related toxins. The limit of detection (LOD) of SEB achieved within few minutes was 50 ng/mL visually and spectrometric method improved it to 0.5 ng/mL. Robustness of the assay was tested in artificially spiked milk samples and cross-checked using in house developed sandwich ELISA (IgY as capturing and SEB specific monoclonal as revealing antibody) and PCR. This colorimetric assay could be a suitable alternative over existing methods during biological emergencies due to its simplicity, sensitive and cost effectiveness.
Highlights
Development of highly sensitive, rapid response and super miniaturized sensors against toxin which can be weaponized to even a sub toxic dose is of uttermost importance for food security
Staphylococcal enterotoxin B (SEB) with its high stability to thermal and proteolytic activity is the primary cause of food poisoning and induces gastrointestinal symptoms such as emesis and diarrhea currently listed as a category B Bio-weapon agent (Singh et al, 2010)
In our previous report we have reported a single-stranded DNA aptamer (SEB2) that binds to enterotoxin B and able to detect in low nanomolar range (Mondal et al, 2015)
Summary
Development of highly sensitive, rapid response and super miniaturized sensors against toxin which can be weaponized to even a sub toxic dose is of uttermost importance for food security. Over the last few years, several sensitive and selective methods to detect SEB have been reported based on different detectors. These are based on electrical methods, electrochemical sensor (Chatrathi et al, 2007), magneto elastic sensor (Ruan et al, 2004), piezoelectric sensors (Lin and Tsai, 2003), cantilever sensor (Campbell et al, 2003) and electrical percolation-based sensor (Yang M et al, 2010). A number of optical method have been developed based on Colorimetric Detection of SEB
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
