Nano-liter size droplet dispenser using electrostatic manipulation technique

A new dispenser made of Teflon that uses electrostatic manipulation technique to dispense nano-liter size droplets based on the electrostatic actuation mechanism has been developed. Two types of dispensers were developed, viz. a single-hole type (Teflon tube) and a multiple-hole dispenser (Teflon block). The single-hole type dispenser successfully dispensed droplets of a solution supplied by a syringe pump on an electrode panel surface; and thus the droplets become available for subsequent manipulation on the electrode panel. Based on the same principle, a compact Teflon block dispenser was designed that can simultaneously dispense five different solutions in a small area (30 mm). The size of dispensed droplets can be controlled by various factors, e.g., flow rate of solution, dispensing height, applied voltage, frequency of voltage pattern. We could dispense the droplets in the range of 55–210 ± 8 nL. This technique can be applied for automation of repetitive pipetting and screening operations in protein crystallization.