Functional extensions of Dip Pen NanolithographyTM: active probes and microfluidic ink delivery

Dip Pen Nanolithography (DPN) is an important technique for nanotechnology and a fundamental new tool for studying the consequences of miniaturization. In this scanning probe technique a sharp tip is coated with a functional molecule (the ‘ink’) then brought into contact with a surface where it deposits ink via a water meniscus. The DPN process is a direct-write pattern transfer technique with nanometer resolution and is inherently general with respect to usable inks and substrates, including biomolecules such as proteins and oligonucleotides. We present functional extensions of the basic DPN process by showing multiple active probes along with the ability to load different inks onto probe tips. We present the fabrication process and characterization of thermomechanically actuated probes that use the bimorph effect to induce deflection of individual cantilevers as well as the integration of these probes with control electronics and an interface module. As an additional improvement to DPN functionality, we developed the capability to write with different inks on the probe array, permitting the fabrication of multicomponent nanodevices in one writing session. For this purpose, we fabricate passive microfluidic devices and present the microfluidic behavior and ink loading performance of these components. (Some figures in this article are in colour only in the electronic version)