Detection of Bacillus Subtilis Spores Using Peptide-Functionalized Cantilever Arrays

Author(s): Dhayal, Babita, Walter A. Henne, Derek D. Doorneweerd, Ronald G. Reifenberger, Philip S. Low

Journal: J. Am. Chem. Soc. (2006) 128: 3716-3721.

Abstract:
We move beyond antibody-antigen binding systems and demonstrate that short peptide ligands can be used to efficiently capture Bacillus subtilis (a simulant of Bacillus anthracis) spores in liquids. On an eight-cantilever array chip, four cantilevers were coated with binding peptide (NHFLPKV-GGGC) and the other four were coated with control peptide (LFNKHVP-GGGC) for reagentless detection of whole B. subtilis spores in liquids. The peptide-ligand-functionalized microcantilever chip was mounted onto a fluid cell filled with a B. subtilis spore suspension for ~40 min; a 40 nm net differential deflection was observed. Fifthmode resonant frequency measurements were also performed before and after dipping microcantilever arrays into a static B. subtilis solution showing a substantial decrease in frequency for binding-peptidecoated microcantilevers as compared to that for control peptide cantilevers. Further confirmation was obtained by subsequent examination of the microcantilever arrays under a dark-field microscope. Applications of this technology will serve as a platform for the detection of pathogenic organisms including biowarfare agents.