Robotic liquid handling system for microdispensing of highly viscous reagent

A robotic liquid handling system is developed for dispensing highly viscous reagent with nanoliter volumes. The robot in question is of immediate need in protein crystallization research and in electronics packaging field. In this paper, the system structure is introduced which mainly consists of three modules: motion control module, dispense control module and droplet volume measure module. Highly viscous reagent can be dispensed in nanoliter through controlling the dispense control module and the motion control module correctly, and the volume of micro-drop can be measured based on robotic vision technique. The factors that influence the successful delivery of nanoliter volumes of highly viscous reagent are discussed through analysis of the dispensing process. And the two critical values that the dispense height should be kept are derived. Finally, three kinds of reagent with different viscosity are used for dispensing experiments to verify the theoretical results. The accuracy of the system has been shown to be below 7%, and the coefficient of variance (CV) has been shown to be below 10%.