Nikolas Sochorakis


We have studied the conditions leading to robust spraying in linear arrays of electrosprays in which the counter electrode is far compared to the inter-emitter separation. In our design, a row of emitter tubes protrude out of a backplate, and the counter electrode is a flat collector plate set at a high negative potential. In addition, electrodes at both ends of the array enable uniform electrical field conditions, while preventing electrical gaseous discharges. We show that this geometry is scalable without bound under different geometrical configurations and operation conditions. This conclusion is in agreement with electric field computations in simplified geometries. The same electrospray setup has been used to generate polymer micro/nano particles loaded with curcumin as an active pharmaceutical ingredient (API). An ethanol solution of curcumin and a highly hydrophilic polymer, polyvinylpyrrollidone (PVP), has been electrospray dried using the linear electrospray array. The result has been PVP-curcumin spherical particles of 0.5 ?m average size, for improving curcumin water solubility. To facilitate the collection of the produced particles a horizontal deflection electrode has been implemented to enforce periodicity in the sprays and the particle collections spots. Also first reported here is the continuous collection of electrosprayed particles onto paper substrates at ambient conditions. Finally, based on the idea of paper as substrate material, a single emitter electrohydrodynamic (EHD) jet printing device has been developed for the deposition of protein lines onto nitrocellulose strips. Through a collaboration with a biology group from the same university we have successfully printed a lateral flow assay biosensor that gives colorimetric signal upon the detection of the specific DNA sequence of human papilloma virus.