Affinity-Selected Filamentous Bacteriophage as a Probe for Acoustic Wave Biodetectors of Salmonella typhimurium

• Main Authors: Olsen, Eric V, Sorokulova, Iryna B, Petrenko, Valery A, Chen, I-Hsuan, Barbaree, James M, Vodyanoy, Vitaly J
• Format: Report
• Language: English
• Subjects: ACOUSTIC WAVES; Active & Passive Radar Detection & Equipment; ADSORPTION; BACTERIOPHAGES; BIOLOGICAL AGENT DETECTORS; Chemical, Biological and Radiological Warfare; CRYSTALS; DEPOSITION; ELECTRON MICROSCOPY; FILAMENTS; FLUORESCENCE; LINEAR REGRESSION ANALYSIS; Microbiology; PIEZOELECTRIC TRANSDUCERS; PROBES; QUARTZ; RESONANT FREQUENCY; SALMONELLA TYPHIMURIUM; SCANNING ELECTRON MICROSCOPES; VISCOSITY

Proof-in-concept biosensors were prepared for the rapid detection of Salmonella typhimurium in solution, based on affinity-selected filamentous phage prepared as probes physically adsorbed to piezoelectric transducers. Quantitative deposition studies indicated that 3 x 10 to the 10th power phage particles per square cm could be irreversibly adsorbed for 1 h at room temperature to prepare working biosensors. The quality of phage deposition was monitored by fluorescent microscopy. Specific bacterial binding resulted in resonance frequency changes of prepared sensors, which were evaluated using linear regression analysis. Sensors possessed a rapid response time 180 s, had a low detection limit of 100 cells/ml and were linear over a range of 10 to 10 to the 7th power cells/ml with a sensitivity of 10.9 Hz per order of magnitude of S. typhimurium concentration. Viscosity effects due to increasing bacterial concentration and non-specific binding were not significant to the piezoelectric platform as confirmed by dose-response analysis. Phage-bacterial binding was confirmed by fluorescence and scanning electron microscopy. Overall, phage may constitute effective bioreceptors for use with analytical platforms for detecting and monitoring bacterial agents, including use in food products and possibly biological warfare applications. Supported in part by DARPA (contract no. MDA972-00-1-0011); ARO/DARPA (contract no. DAAD19-01-1-0454); NIH (contract no. NIH-1-R21-AI055645); and USDA (contract no. 99-34394-7546).