Use of magnetic nanoparticles for mixing in microarrays and microsystems
Doctor of Philosophy
Microarrays have found widespread use for probing genomic and proteomic 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. This thesis describes various approaches for providing solution movement and mixing within this confined geometry by employing functionalized magnetite nanoparticles that are included within the target solution and an external applied magnetic field that together provide mixing within the microarray chamber. The effects of particle size, the concentration, the magnetic path and its movement have each been investigated, resulting in an optimization of accelerated mixing within the chamber. The nanoparticles used in this study were prepared to include surface functional groups to make them non-interacting with the microarray surface or toward target molecules in solution. They are readily removed from the system during a rinsing step prior to reading of a microarray. The approach of mixing by magnetic nanoparticles accelerated timescales for microarray experiments and also improved quality of data sets.