Ultrasensitive detection of Vibrio cholerae O1 using microcantilever-based biosensor with dynamic force microscopy

This work presents the first demonstration of a cantilever based cholerae sensor. Dynamic force microscopy within atomic force microscope (AFM) is applied to measure the cantilever's resonance frequency shift due to mass of cell bound on microcantilever surface. The Vibrio cholerae 01, a food and waterborne pathogen that caused cholera disease in human, is a target bacterium cell of interest. Commercial gold-coated AFM microcantilevers are immobilized with monoclonal antibody (anti-V. cholerae 01) by self-assembled monolayer method. V. cholerae 01 detection experiment is then conducted in concentrations ranging from 1 x 10(3) to 1 x 10(7) CFU/ml. The microcantilever-based sensor has a detection limit of similar to 1 x 10(3) CFU/ml and a mass sensitivity, Delta m/Delta F, of similar to 146.5 pg/Hz, which is at least two orders of magnitude lower than other reported techniques and sufficient for V. cholerae detection in food products without pre-enrichment steps. In addition, V. cholerae 01 antigen-antibody binding on microcanilever is confirmed by scanning electron microscopy. The results demonstrate that the new biosensor is promising for high sensitivity, uncomplicated and rapid detection of V. cholerae O1. (C) 2010 Elsevier B.V. All rights reserved.