Development of an in Situ Lost-Cost Radiofrequency Sensor to Monitor Bacteria and / or Biofilm Growth

This paper presents the use of a real-time and label-free radiofrequency sensor applied to the monitoring of marine bacteria and / or biofilm growth. Its principle is based on an openended coaxial probe sensitive to the variation of the electrical conductivity of the probed medium in the microwave range. A well-known marine bacterium (vibrio fischeri) was considered. Two different probes were used. The solution was monitored as a function of time at different frequencies (100,300 and 500 MHz). Sensibility to bacteria growth differed between probes. In addition, the high conductivity of the nutrient liquid makes it difficult to monitor bacteria growth.