In order to preserve the environment from toxic contaminants and pathogens that can be released into a variety of media (such as air, soil, and water), the detection of biological and chemical species in atmosphere, process gases, water, and soil is of a great concern. In particular, the ability to quickly and efciently detect the presence or absence of specic chemicals can be a matter of life or death. Leaks of toxic gases, monitoring of glucose or anesthetics in the bloodstream, and testing for harmful compounds in foods all require selective, sensitive, fast, and reliable devices.