TopSpot® Vario: a novel microarrayer system for highly flexible and highly parallel picoliter dispensing

The standard TopSpot® technology has been successfully used in the recent years for the highly parallel nanoliter dispensing of bio-chemical substances for microarray printing. It is based on a pneumatically actuated printhead which enables non-contact microarray fabrication at a pitch of typically 500 µm. This paper reports on a new and improved way of operating the printheads termed TopSpot® Vario technology, using an incompressible material between the piezo actuator and the dispensing medium. The advantage of the incompressible medium is the direct relation between the displacement amplitude and the ejected liquid volume. Earlier reports stated that the filling of the printheads is a key issue. In this paper we report on the implementation and characterization of a new printhead design including microchannels for bubble free priming of blind channels. Microarray fabrication was successfully conducted with four different types of protein.