(579g) Microelectrode-Based System for Cell Adhesion Detection and in Vivo Biofilm Monitoring

Bacteria frequently attach to medical devices such as intravascular catheters by forming multicellular communities known as biofilms, which are the source of many infections that are unable to be tamed by systemic antibiotic therapy. This research is devoted to the characterization of the passive electrical parameters of biological cells adhered to the surface by means of the time-domain impedance spectroscopy in combination with chrono-potentiometry measurements. When a small perturbation signal applied to a microorganisms adhered to the surface changes the distribution of ions in the electrostatic double layer, as well as the diffusive part of double layer just outside of the double layer. High polarization is manifested as a relative complex permittivity that may be much greater than that of the suspending medium. Specially designed micron-sized electrode allows to monitor bacterial adhesion at the level of single colony-forming unit. As a result of biofilm growth, exponential changes in open circuit potential of the microelectrode surface were observed. Combination of fluorescence microscopy and impedance analysis allows monitoring of total bacterial amount and structural organization of biofilms. Experimental data and theoretical model of biofilm development and corresponding changes in the impedance spectra are discussed.