Chlorella sensors in liquid marbles and droplets

The use of live organisms in electrically-coupled sensing devices has been suggested as an alternative low-cost, low-environmental footprint and robust technology for continuous monitoring and sensing applications. The utility of Chlorella vulgaris algae as living biosensor media inside liquid marbles (LMs), micro-wells and surface recesses is here explored, through noninvasive measurement of electrical activity via indirect monitoring of culture media. We present results demonstrating the suitability of this organism in several experimental setups which may be adapted to a wide range of applications, and evaluate how to maximise sensing performance through optimising electrode geometry, environmental controls and, in the case of LMs, coating parameters. We conclude by discussing potential applications and further optimisations.