The Whole Cell Sol-Gel Imprinting on Au Interface: A Tool for Detection

Accurate and fast identification and sensitive detection of microorganisms is required to optimize the clinical management of infected patients, and to limit food poisoning and environmental disasters on a wider range. Molecular imprinting is a method in which an appropriate functional monomer is polymerized in the presence of a template forming covalent or non-covalent bonds with the functional monomer. Afterward, following polymerization process, the template is removed that leaves a space or cavity originally occupied by the tem-plate molecule, in its original shape. These cavities due to their steric shape can adopt and bind similar or analogous molecule with pronounced selectivity and sensitivity. The next step in this interesting methodology was to imprint much more complex organic structures such as whole cells in sol-gel matrices, termed macromolecular imprinting. In this work a detection strategy that does not require expensive biological affinity agents and can be tailored at will to any microorganism target with minimal change in the technological approach was developed. This goal was obtained by the development of a bacteria imprinted matrix deposited on gold interfaces allowing the use of electrochemical impedance spectroscopy. We used the potential of microorganism imprinting into sol-gel for the selective capture of pathogens. Chemically removing the biological template results in complementary cavities that spatially fit and recognized a specific microorganism. Firstly, the non-imprinted and imprinted electrodes have been prepared using sol-gel method. Several microscopic and spectroscopic techniques have been applied for characterization of the prepared electrodes. Finally, electrochemical impedance spectroscopy has been utilized for determination of bacteria in the range of 102 CFU/mL-106CFU/mL.