Rapid and sensitive detection of cholera toxin using gold nanoparticle-based simple colorimetric and dynamic light scattering assay

• Published in: Analytica chimica acta 2015-09, Vol.892, p.167-174
• Main Authors: Khan, Sadia Afrin, DeGrasse, Jeffrey A., Yakes, Betsy Jean, Croley, Timothy R.
• Format: Article
• Language: English
• Subjects: Antibodies - chemistry; Antibodies - immunology; Cholera toxin; Cholera Toxin - analysis; Cholera Toxin - immunology; Colorimetric assay; Dynamic Light Scattering; Dynamic light scattering assay; Gold - chemistry; Gold nanoparticle; Metal Nanoparticles - chemistry; Spectrophotometry, Ultraviolet; Water Microbiology
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2015.08.029

Herein, a rapid and simple gold nanoparticle based colorimetric and dynamic light scattering (DLS) assay for the sensitive detection of cholera toxin has been developed. The developed assay is based on the distance dependent properties of gold nanoparticles which cause aggregation of antibody-conjugated gold nanoparticles in the presence of cholera toxin resulting discernible color change. This aggregation induced color change caused a red shift in the plasmon band of nanoparticles which was measured by UV–Vis spectroscopy. In addition, we employed DLS assay to monitor the extent of aggregation in the presence of different concentration of cholera toxin. Our assay can visually detect as low as 10 nM of cholera toxin which is lower than the previously reported colorimetric methods. The reported assay is very fast and showed an excellent specificity against other diarrhetic toxins. Moreover, we have demonstrated the feasibility of our method for cholera toxin detection in local lake water. [Display omitted] •Gold nanoparticle based colorimetric and dynamic light scattering assay was developed for cholera toxin.•The reported assay is sensitive enough to visually detect as low as 10 nM of cholera toxin.•This assay is very fast and can specifically recognize cholera toxin over other diarrhetic toxins.