Rapid SERS Detection of Botulinum Neurotoxin Type A

Abstract

Surface-enhanced Raman scattering (SERS) is a powerful technique for decoding of 2-5-component mixes of analytes. Low concentrations of analytes and complex biological media are usually non-decodable with SERS. Recognition molecules, such as antibodies and aptamers, provide an opportunity for a specific binding of ultra-low contents of analyte dissolved in complex biological media. Different approaches have been proposed to provide changes in SERS intensity of an external label upon binding of ultra-low contents of the analytes. In this paper, we propose a SERS-based sensor for the rapid and sensitive detection of botulinum toxin type A. The silver nanoisland SERS substrate was functionalized using an aptamer conjugated with a Raman label. The binding of the target affects the orientation of the label, providing changes in an analytical signal. This trick allowed detecting botulinum toxin type A in a one-stage manner without additional staining with a monotonous dose dependence and a limit of detection of 2.4 ng/mL. The proposed sensor architecture is consistent with the multiarray detection systems for multiplex analyses.

Nanoisland SERS-Substrates for Specific Detection and Quantification of Influenza A Virus

“…The possible reason for a high LoD is a distortion in the nanostructured surface similar to that reported in references [22,23]. Recently, the production of silver nanoislands on silica oxide substrates was optimized to increase the adhesion of the nanoparticles [26]. Here we step-by-step optimize the setup of our aptasensor, decreasing the distortion of the surface and providing characteristics comparable to the best examples of the published SERS aptasensors.…”

Recent Advances in Aptamer-Based Biosensors for Bacterial Detection

“…However, the selection of aptamers to target small-molecule toxins faces challenges such as the inefficient separation of bound and unbound DNA, limited binding motifs on target surfaces, a lack of chemical groups for target immobilization, and difficulties in distinguishing between molecules with similar structures. Among the few aptamers for toxins documented in the current literature are enterotoxins, cholera toxins, and botulinum toxins, produced by S. aureus, Vibrio cholerae, and C. botulinum, respectively [43][44][45][46][47][48][49][50][51][52].…”

Aptamer-Based Biosensors for Bacterial Detection

“…Indeed, some bacterial toxins can survive the pasteurization process and have a high degree of resistance to high temperatures (<100 °C), making them indicative of the past or current presence of bacteria. For instance, SELEX methods against toxins have been implemented, and aptamers have been discovered to identify toxins of S. aureus, Vibrio cholerae, and C. botulinum, named enterotoxins, cholera toxin, and botulinum toxins, respectively [41][42][43][44][45][46].…”