There is strong current interest in the use of GaN- and ZnO-based materials for gas, biological and chemical sensing. Both ZnO and the AlGaN/GaN heterostructure systems are piezoelectric, leading to large changes in charge density when the ambient or surface condition is changed and nitride HEMTs are also being developed for next generation wireless communication systems. Therefore it is possible to integrate on-chip wireless data transmission with the sensors, providing remote sensing capability and the ability to integrate with blue or ultra-violet light-emitting diodes (LEDs) for directed cell growth or remediation. In this talk we will give examples of using ZnO nanorods and nitride HEMTs for pH sensing in the range of interest for human blood (7-8 pH), detection of DNA hybridization and detection of Hg. The mercury (II) (Hg2+) ion is one of the environmentally most important cations whose toxicity has long been recognized as a chronic environmental problem. Development of the basic science of improving the detection efficiency for nuclear agents such as Pu-240 (weapons-grade plutonium typically contains about 5 percent plutonium-240) is needed. In all of these sensor systems, integrating the resulting sensors with modern GPS and wireless communication systems in a convenient module is important for ease of use and monitoring applications.