Bio-droplet manipulation and characterization by ferroelectric photovoltaic platforms

Ferroelectric crystals generate electric fields under optical and thermal excitation. Recently, photo-induced electric fields generated in photovoltaic ferroelectric crystals have been applied to act on liquid droplets, either to manipulate droplets or to generate tiny droplets from a liquid reservoir. In this work, we investigate the migration of water and aqueous biodroplets under the light-induced electric fields generated in ferroelectric platforms based on iron doped lithium niobate. Different parameters affecting droplet manipulation have been analysed in detail. Light intensity, distance to the photovoltaic substrate and orientation of the polar axis of the active substrate play a key role. The behaviour and analysis of the droplet motion combined with numerical simulations allow to characterize the droplets and, in particular to distinguish between neutral and charged droplets. The results show the potential of this technique in biotechnology and biomedicine for applications such as bio-droplet analysis or sensing.