Microelectronic DNA arrays have been developed for point mutation, single nucleotide polymorphism (SNP), short tandem repeats (STRs) and gene expression analysis. In addition to a variety of molecular biology and genomic research applications, such devices will also be used for infectious disease detection, genetic and cancer diagnostics; forensic and genetic identification; on-chip DNA/RNA amplification and pharmacogenomic applications. These microelectronic array devices are able to produce defined electric fields on their surfaces that allows charged molecules and other entities to be transported to or from any test-site or microlocation on the planar surface of the device. These molecules and entities include DNA, RNA, proteins, enzymes, antibodies, cells, nanoparticles, and even micron scale semiconductor devices. Microelectronic arrays have been developed with 25, 100, 400, 1200, 1600, and 10,000 microlocations (test sites) that can range in size from 30 microns, to 80 microns. The microelectronic chip or array device is incorporated into a cartridge package that provides the electronic, optical, and fluidic interfacing. A complete instrument system provides a chip loader, fluorescent reader; and computer interface and data display screen. In addition to the genomic and diagnostic applications, microelectronic array technology may ultimately lead to nanofabrication processes for the controlled manipulation and heterogeneous integration of molecular scale, nanoscale and microscale components.