High-speed, Thermo-chemical Nanolithography for Biological Applications

Scanning probe-based chemical nanolithography has been recognized as an essential part of future nanofabrication processes. However, most of the present strategies still have significant limitations in terms of throughput, resolution and substrate variety. Recently, we have developed a new chemical nanolithography technique called thermo-chemical nanolithography (TCNL). TCNL utilizes a resistively-heated atomic force microscope tip to thermally activate a chemical reaction on an arbitrary organic or inorganic substrate surface. TCNL can write well-defined chemical features at a rate of mm/s, with sub-15 nm resolution [1]. In particular, we have demonstrated that carboxylic ester groups on a polymer surface can be deprotected by TCNL to give carboxylic acids and further modified to form anhydrides [2]. Therefore, TCNL can tune surface wettability with in situ write-read-overwrite capability. In addition, nanoarrays of TCNL-activated amine groups have been used as anchor sites to immobilize a variety of biological ligands [3]. This proves TCNL to be a powerful tool to control the physical placement of biomolecules and cells. It can be applied to a range of molecular cell biology studies such as ligand-receptor recognition and cell signaling.1. R. Szoszkiewicz, T. Okada, S. C. Jones, T.-D. Li, W. P. King, S. R. Marder, and E. Riedo, Nano Lett. 7, 1064 (2007).2. D. B. Wang, R. Szoszkiewicz, T. Okada, S. C. Jones, M. Lucas, J. Lee, W. P. King, S. R. Marder, and E. Riedo, Appl. Phys. Lett. 91, 243104 (2007).3. D. Wang, V. Kodali, W. D. Underwood, J. E. Jarvholm, T. Odaka, S. J. Jones, C. Rumi, W. P. King, S. R. Marder, J.E. Curtis and E. Riedo, (2008) in preparation.