Monitoring of Microalgae Lipid Accumulation Using RF Open Ended Biosensor

This letter presents an original approach to monitor the lipid intracellular content of microalgae by the radio frequency (RF) analysis of the broadband dielectric characterization. This study shows that the lipid quantification can be deduced from the complex dielectric spectra properties extracted from the reflection coefficient (S11) measurement. A calibration of the open-ended coaxial biosensor is performed using three different conditions (vacuum, water, and methanol) from which the complex dielectric behavior is well known. From the microalgae RF measurements, the complex permittivity spectrum of the biological samples is estimated up to 3 GHz. In this way, the microalgae lipid content and, thus, its state of accumulation can be further monitored using this RF biosensor.