DNA as Invisible Ink for AFM Nanolithography

Jian Liang†, Matteo Castronovo†‡, and Giacinto Scoles*†

Department of Biology, Temple University, 1900 North 12th Street, Philadelphia, Pennsylvania 19122, United States

Experimental and Clinical Pharmacology Unit, CRO-National Center Institute, Via Franco Gallini 2, I-33081 Aviano Pordenone, Italy

J. Am. Chem. Soc., Article ASAP

DOI: 10.1021/ja2076845

We have used nanografting, an atomic force microscopy (AFM)-based nanolithography technique, to fabricate thiolated DNA nanostructures on gold surfaces. The tip-guided assembly offers opportunities for locally controlling the packing order, density, and thus the thickness of the DNA patterns. By selecting proper nanografting parameters, we can embed single-stranded DNA (ssDNA) patches into a background composed of the same DNA molecule prepared by self-assembly, in which the patches remain topographically (and chemically) invisible but have much improved packing order. When the complementary DNA (cDNA) is added, the thickness of the nanografted layer increases much more dramatically than that of the self-assembled layer during the hybridization process, and as a result, the pattern emerges. Interestingly, the pattern can be reversibly hidden and shown with high fidelity simply by dehybridizing and appending the cDNA repeatedly.