SBIR Phase II: Microfabricated Silicon Devices for Low Cost Microarray

This Small Business Innovation Research (SBIR) Phase II project proposes to develop a new, commercially viable micromachined silicon technology platform for the printing of DNA microarrays that offer significant advantages over current steel pin technology in cost and in quality. The Phase I effort demonstrated very clearly that a silicon pin reliably imbibed DNA printing solution and deposited spots with a size variance better than that of commercial steel printing pins. Phase II work will focus on the development of a new micromachining protocol based on a combination of wet and dry etching that will allow sculpting of the print tip in all three dimensions. This, in turn, will permit the size, shape and fluid delivery characteristics of the tip to be finely tuned. Printing tip sizes (range : 125 microns x 125 microns to 25 microns x 25 microns) and uptake volumes (range : 0 to 100nL) will allow the pins to precisely take up and deliver any volume or spot size/shape desired. Combined with a much denser packing of pins into a newly designed, all-silicon holder, these attributes will allow DNA microarrays to be fabricated at a cost, speed and quality previously unobtainable. The commercial application of this project is in the area of DNA microarrays. Due to the weaknesses in the current manually machined steel pins used for printing DNA microarrays (such as extremely high manufacturing costs and low yield, poor pin-to- pin uniformity, the limited range of spot sizes deposited, waste of valuable DNA in uptake and delivery dead volumes, and deposit variability with time due to rapid tip wear), there is an urgent need for an improved printing technology. The new micromachined silicon printing product to be developed in this project will largely eliminate these drawbacks, and therefore will be well positioned for market entry as a replacement for existing products by virtue of its lower cost, superior accuracy and speed.