The goal of this research is to develop novel, biologically functional DNA nanostructures that dramatically enhance the reproducibility, sensitivity, and spatial density of chip-based DNA assays. These nanostructures will improve applications ranging from point-of-care diagnosis to genomic arrays used in basic research by enabling the development of next generation screening technologies that are faster, more sensitive, more reliable, and possibly more cost effective than those presently available in the life sciences market. To accomplish the stated goals, Nanolnk will develop a DNA patterning methodology based on Dip Pen Nanolithography (DPN) to generate sub-micron sized features of DNA on solid surfaces. This multidisciplinary effort will involve life and physical scientists at Nanolnk, MEMs and instrumentation engineers at our fabrication facility, in addition to support from outside experts in the fields of DNA microarrays and microfabrication. DPN, built upon the technique of Atomic Force Microscopy (AFM), allows one to deposit materials uniformly in a direct-write fashion on surfaces with nanoscale spatial precision. This strategy offers significant advantages over current microarray printing technologies that suffer from poor spot to spot reproducibility in terms of size, shape, and oligonucleotide density, as well as reproducibility across microarray slides. Preliminary work has demonstrated that the DPN technique can be used to deposit 12mer synthetic oligonucleotides on surfaces with extremely uniform sub-100 nm to several micron scale features. The DNA nanostructures formed robust films and exhibited selectivity in binding to complementary oligonucleotides. Thus, DPN can be used to generate uniform features of synthetic DNA far smaller than can be obtained with other spotting or photolithography techniques. In Phase I, Nanolnk will demonstrate feasibility of the DPN-based approach for generating sub-micron scale DNA nanostructures on glass surfaces. The resulting nanostructures will be analyzed using existing fluorescence probe technology to provide benchmarking standards for comparison to conventional microarray assays. In addition, for applications in life sciences and biomedicine, it is desirable and advantageous in terms of speed and throughput to extend the serial patterning capability of DPN to a parallel methodology. Thus, concurrent with ink development and patterning optimization, microfabricated parallel multipen arrays will be explored as a means for faster, simultaneous writing of multiple DNA inks.
