Active microelectronic chip devices which utilize controlled electrophoretic fields for multiplex DNA hybridization and other genomic applications

Microelectronic DNA chip devices that contain planar arrays of microelectro des have been developed for multiplex DNA hybridization and a variety of ge nomic research and DNA diagnostic applications. These devices are able to p roduce almost any desired electric field configuration on their surface. Th is ability to produce well-defined electric fields allows charged molecules (DNA, RNA, proteins, enzymes, antibodies, nano-beads, and even micron scal e semiconductor devices) to be electrophoretically transported to or from a ny microlocation on the planar surface of the device. Of key importance to the device function is the permeation layer which overcoats the microelectr odes. The permeation layer is generally a porous hydrogel material that all ows water molecules and small ions (Na+, Cl-, etc.) to freely contact the m icroelectrode surface, but impedes the transport of the larger analytes (ol igonucleotides, DNA, RNA, proteins, etc.). The permeation layer prevents th e destruction of DNA at the active microelectrode surface, ameliorates the adverse effects of electrolysis products on the sensitive hybridization rea ctions, and serves as a porous support structure for attaching DNA probes a nd other molecules to the array. In order to maintain rapid transport of DN A molecules,facilitate hybriziation, and work within constrained current an d voltage ranges, low conductance buffers and various electronic pulsing sc enarios have also been developed. These active microelectronic array device s allow electrophoretic fields to be used to carry out accelerated DNA hybr idization reactions and to improve selectivity for single nucleotide polymo rphism (SNP), short tandem repeat (STR), and point mutation analysis.