A Bioanalytical Platform for Simultaneous Detection and Quantification of Biological Toxins

Abstract

Prevalent incidents support the notion that toxins, produced by bacteria, fungi, plants or animals are increasingly responsible for food poisoning or intoxication. Owing to their high toxicity some toxins are also regarded as potential biological warfare agents. Accordingly, control, detection and neutralization of toxic substances are a considerable economic burden to food safety, health care and military biodefense. The present contribution describes a new versatile instrument and related procedures for array-based simultaneous detection of bacterial and plant toxins using a bioanalytical platform which combines the specificity of covalently immobilized capture probes with a dedicated instrumentation and immuno-based microarray analytics. The bioanalytical platform consists of a microstructured polymer slide serving both as support of printed arrays and as incubation chamber. The platform further includes an easy-to-operate instrument for simultaneous slide processing at selectable assay temperature. Cy5 coupled streptavidin is used as unifying fluorescent tracer. Fluorescence image analysis and signal quantitation allow determination of the toxin’s identity and concentration. The system’s performance has been investigated by immunological detection of Botulinum Neurotoxin type A (BoNT/A), Staphylococcal enterotoxin B (SEB), and the plant toxin ricin. Toxins were detectable at levels as low as 0.5–1 ng·mL−1 in buffer or in raw milk.

Diverse Applications of Electronic-Nose Technologies in Agriculture and Forestry

“…The strongest trend appears to be the expanded utilization of e-nose devices as a monitoring tool in the food industry, assuring the safety and quality of consumable plant products, continuing with the development of new methods to detect chemical contaminants [350,391], adulterations with baser elements [190,259,260], food-borne microbes and pathogens [263,351,392–395], and toxins [84,311,396] in crops and food products. Similarly, new food-analysis e-nose methods are being developed to detect changes in VOCs released from foods and beverages in storage to assess shelf-life [346,397,398] and quality [185,206,399–403], and for chemical analyses [404,405], classifications [227,232,346,406,407], and discriminations [162,218,228,408] of food types, varieties and brands.…”

Ricin detection: Tracking active toxin

“…The use of microspheres generated an increase in collective surface area, providing improvements in sensitivity and assay time, while a magnetoelastic sensor surface also helped to reduce total assay time. The use of microarrays, which include panels of antibodies for simultaneous detection of a variety of antigenic targets of interest, allowed multiplexed detection of ricin in parallel with other harmful toxic agents, such as cholera toxin, staphylococcal enterotoxins A and B, Bacillus globigii, botulinum toxin A, Yersinia pestis, and heat labile toxin of Escherichia coli, and provided dramatic improvements in assay utility and flexibility (Delehanty and Ligler, 2002;Garber et al, 2010;Simonova et al, 2012;Wadkins et al, 1998;Weingart et al, 2012). In other works, the toxin capture antibodies used as receptors were substituted by DNA/RNA aptamers (Haes et al, 2006;Kirby et al, 2004;Lamont et al, 2011), single domain antibodies (Anderson et al, 2013;Shia and Bailey, 2013;Stine et al, 2005), and sugar-conjugated materials (Huebner et al, 2013;Liu et al, 2011).…”

Conjugated fluorescent polymer sensor for proteolytic activity detection with designed specificity

“…Overall, our feasibility study reveals that functional detection of 5 pg or 33 amol of BoNT‐A in 5 µL samples in under 2 h is possible. Detection of BoNT‐A at a picomolar concentration is comparable to that achieved by other methods, such as immuno‐based microarray, lab‐on‐a‐chip and fluorescent resonance energy transfer . While detection of BoNT‐A has been reported at even lower, femtomolar, concentrations using surface plasmon resonance, microfluidic arrays with self‐assembled monolayers, flow cytometry and enzyme‐linked immunosorbent assay, our approach is flexible and open to further optimization, which can possibly improve the sensitivity of the method in the future.…”