Selection of affinity peptides for interference-free detection of cholera toxin

초록

Cholera toxin is a major virulent agent of Vibrio cholerae, and it can rapidly lead to severe dehydration, shock, causing death within hours without appropriate clinical treatments. In this study, we present a method wherein unique and short peptides that bind to cholera toxin subunit B (CD-B) were selected through M13 phage display. Biopanning over recombinant CIX-B led to rapid screening of a unique peptide with an amino acid sequence of VQCRLGPPWCAIC, and the phage-displayed peptides analyzed using ELISA, were found to show specific affinities towards CTX-B. To address the use of affinity peptides in development of the biosensor, sequences of newly selected peptides were modified and chemically synthesized to create a series of affinity peptides. Performance of the biosensor was studied using plasmonic-based optical techniques: localized surface plasmon resonance (LSPR) and surface-enhanced Raman scattering (SERB). The limit of detection (LOD) obtained by LSPR with 3a-rule was 1.89 ng/mL, while SERS had a LOD of 3.51 pg/mL. In both cases, the sensitivity was much higher than the previously reported values, and our sensor system was specific towards actual CIX-B secreted from V. cholera, but not for CTX-AB5.

키워드