Authors: A. Meister, J. Przybylska, P. Niedermann, C. Santschi, H. Heinzelmann
Affilation: CSEM SA, Switzerland
Pages: 273 - 276
Keywords: nanoscale dispensing, AFM, microarray
The demand for specific tools intended for the deposition of small amount of material on a nanoscale at predefined location is continuously increasing. Several dispensing tools for liquid, such as ink-jet or pin-spotting heads have been developed. They are currently widely used for various applications, such as for writing microarrays used in proteomics and genomics. However, such printing tools have some limitation regarding the volume of deposited material. To enable the printing of nanometer sized droplets with volumes in the femto and attoliter range and sub-micron droplet spacing, a nanoscale dispenser (NADIS) based on an atomic force microscopy (AFM) probe has been developed. The probe consists of a cantilever with a hollow core, which is connected to a reservoir located in the chip. The hollow cantilever acts as a microfluidic channel that connects the reservoir to the dispensing tip located at the free end of the cantilever. The tip possesses an opening at its apex with typical size of 200 nm, in order to allow a transfer of liquid towards the surface. The transfer of liquid from the tip to the surface occurs during an approach-contact-withdrawal cycle and is driven by capillary pressure alone.