(619a) Magnetically Driven Mixing within a Microarray Geometry Using Functionalized Magnetic Nanoparticles

Microarrays have found widespread use for probing genomic and proteinomic functions. These systems consist of a purposefully spotted microscopic slide of different biological samples (the microarray), a sub-milliliter solution volume containing target molecules of interest, and a coverslip to contain and spread the solution over the microarray surface. Incubation times for the target solution with the microarray can be as long as a day to allow binding of target molecules to probes on the array surface. These times are limited by the reliance on diffusional processes for transport within this thin-film geometry. We have pursued approaches for providing solution movement and mixing within this confined geometry enlisting functionalized magnetite nanoparticles that are included within the target solution and an externally sweeping magnetic field that together provide mixing within the microarray chamber. The effects of particle size, concentration, magnetic path, and movement velocity have each been investigated, resulting in an optimization of accelerated mixing within the chamber. The particles have been prepared to incorporate surface functional groups that make them non-interacting with functionalities present on the DNA microarray surface or toward DNA target molecules in solution, thereby providing a component that is readily removed from the system prior to reading of a microarray. A goal of this work has been to reduce the timescale for performing a microarray from roughly a day to a few hours. Our experiments demonstrate the ability for both accelerating timescales as well as for improving the quality and uniformity of data sets by use of the developed mixing strategy.