A Novel Nanoliter Liquid Dispensing Technology for Protein Crystallization

Recently, high-throughput protein crystallization requires the ability to transfer submicroliter volumes of sample with a large range of viscosities. In this paper, a solenoid-based non-contact liquid handling instrument with high-speed flow sensor was developed to meet this requirement. The flow sensor-driven dispenser with feedback control automatically compensates for encountered differences or changes in sample viscosity by adjusting the valve opening time or system pressure. Also, the non-contact liquid dispensing process was investigated with computational fluid dynamics (CFD) models, which make us understand the droplet breakup process in more detail and make dispensing nanoliter droplet fall off successfully without attach to the nozzle. Experiments were carried out with different dispensing volumes, coefficient of variance (CV) has been shown to be below 3% at 1 μl and approach 8% at 50 nl.