We attempted evaluation of biofilm formation by the electrochemical quartz
crystal microbalance (EQCM) method. The EQCM method is applicable to in situ
settings and may be able to determine corrosion and a chemical reaction on materials
under the influence of biofilm formation. We used Au having high chemical stability to
measure frequency and changes of the potential with biofilm formation alone.
Additionally, sample surfaces were examined by a conventional biofilm formation
assay such as fluorescent X-ray analysis and Raman spectroscopy. We conducted three
types of experiments, 1st: rest-potential measurement, 2nd: spontaneous-potential
measurement, and 3rd: constant-potential measurement. From the results of these
measurements, it was concluded that frequency changes depend on changes in the
potential. We investigated biofilm formation by conventional methods of evaluation
and found that the above phenomenon was caused by concentration of ions such as Ca2+
and Cl− from tap water in biofilm. In the positive voltage range, the magnitude of
biofilm formation was inhibited by a halogen ion such as Cl−, whereas in the negative
range, cations such as Ca2+ were concentrated at an accelerated rate. Therefore,
electrochemical evaluation of biofilm formation was carried out successfully by means
of Au, with high chemical stability. In conclusion, the EQCM method appears to be
able to measure biofilm formation.
Keywords: Biofilm, Electrochemical, EQCM, Evaluation, In-situ measurement.
