3D Nanofabrication of Fluidic Components by Corner Lithography

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2012-12, Vol.8 (24), p.3823-3831
• Main Authors: Berenschot, Erwin J. W., Burouni, Narges, Schurink, Bart, van Honschoten, Joost W., Sanders, Remco G. P., Truckenmuller, Roman, Jansen, Henri V., Elwenspoek, Miko C., van Apeldoorn, Aart A., Tas, Niels R.
• Format: Article
• Language: English
• Subjects: 3D nanofabrication; Animals; Cattle; Cell Separation - instrumentation; Cell Separation - methods; Chondrocytes - cytology; dip-pen nanolithography; microfluidics; Microfluidics - instrumentation; Microfluidics - methods; Microscopy, Atomic Force; Microscopy, Electron, Scanning; Nanostructures; Nanotechnology; Nanotechnology - instrumentation; Nanotechnology - methods; nanowires; Nanowires - ultrastructure; Printing - instrumentation; Printing - methods; Thin films
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201201446

A reproducible wafer‐scale method to obtain 3D nanostructures is investigated. This method, called corner lithography, explores the conformal deposition and the subsequent timed isotropic etching of a thin film in a 3D shaped silicon template. The technique leaves a residue of the thin film in sharp concave corners which can be used as structural material or as an inversion mask in subsequent steps. The potential of corner lithography is studied by fabrication of functional 3D microfluidic components, in particular i) novel tips containing nano‐apertures at or near the apex for AFM‐based liquid deposition devices, and ii) a novel particle or cell trapping device using an array of nanowire frames. The use of these arrays of nanowire cages for capturing single primary bovine chondrocytes by a droplet seeding method is successfully demonstrated, and changes in phenotype are observed over time, while retaining them in a well‐defined pattern and 3D microenvironment in a flat array. A new technique for 3D nanofabrication is introduced and its application to the manufacturing of functional fluidic components is shown. One of the components is a 3D cell trapping device shown in the figure. The array of silicon nitride nanowire frames is created by conformal deposition and subsequent isotropic etching of silicon nitride in a mold containing sharp concave corners. This procedure is named corner lithography.