Nano-contact printing of DNA monolayers

Abstract

Technology today is directed towards building smaller devices. To accommodate this development, printing methods are needed. Some printing methods that are used include lithography, micro-contact printing, and inkjet printing. These methods all require specialized instrumentation, hazardous chemicals, and complicated and tedious steps that increase cost of manufacturing. Nano-contact printing is an alternative solution which relies on the specificity of DNA to direct molecules into precise patterns. This study attempts to find the limitations of nano-contact printing through the printing of oligonucleotide monolayers. Eight pattern transfers were made with one master copy and the oligonucleotide surface coverage was analyzed using tapping mode atomic force microscopy (AFM). The percent coverage of oligonucleotide was then calculated from the tapping mode AFM phase images. Two general trends were found. The oligonucleotide surface coverage on the master increased slightly, while the surface coverage on the pattern transfers decreased. One possible explanation for the trends is that the decrease in contact between master and secondary substrate is due to both the accumulation of dirt and the wear and tear of' the master. By improving the contact between master and secondary substrate, the printing method can be expanded from printing monolayers to high resolution patterns.