A single thiolated-phage displayed nanobody-based biosensor for label-free detection of foodborne pathogen

• Published in: Journal of hazardous materials 2023-02, Vol.443 (Pt A), p.130157, Article 130157
• Main Authors: Wang, Peng, Yu, Gege, Wei, Juan, Liao, Xingrui, Zhang, Yao, Ren, Yarong, Zhang, Cui, Wang, Yueqi, Zhang, Daohong, Wang, Jianlong, Wang, Yanru
• Format: Article
• Language: English
• Subjects: Bacteriophages; Biosensing Techniques; Colorimetric detection; Gold; Humans; Immunoassay; Immunosensor; Limit of Detection; Metal Nanoparticles; Nanobody; Phage; Vibrio parahaemolyticus
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2022.130157

Rapid and sensitive detection of bacterial pathogens present in food and environmental samples is of crucial importance to ensure human health and safety. Here, we present a one-step label-free colorimetric strategy based on M13 bacteriophage-displayed nanobody (phage-Nb) derived from camelid heavy-chain antibodies specific to Vibrio parahaemolyticus (V. parahaemolyticus). The thiolation of phage-Nb (Phage-Nb-SH) on pVIII shell proteins induces the aggregation of gold nanoparticles (AuNPs), whereas the specific interaction between nanobody and bacteria prevents the aggregation of AuNPs, resulting in visible color change due to alteration of surface plasmon resonance properties. Based on this phenomenon, a simple and sensitive colorimetric immunosensor for V. parahaemolyticus was developed. The assay can be accomplished within 100 min, and exhibits a visual detection limit of 104 cfu/mL and a quantitative detection limit of 103 cfu/mL, with no cross-reactivity towards other bacterial species. This strategy takes full advantages of both the high specificity of phage-Nbs and the optical properties of AuNPs, enabling simple and rapid detection of bacterial pathogens. [Display omitted] •This is the first report on the establishment of the phage-displayed nanobody library of V. parahaemolyticus.•This work successfully obtained five phage-displayed nanobodies with high affinity and excellent specificity.•This is the first to construct a single phage-Nb-based colorimetric biosensor for bacterial pathogen detection.•This assay can be briefly completed within a one-step addition.•This assay making quantification detection limit of 103 cfu/mL of this biosensor was achieved within 100 min