There is an expanding nano-technology based applications of biosensor for health, medical, food, environmental and other important applications. These biosensor can be used for continuous online and real-time monitoring of changes in life-related processes. 

US scientists have, for example, developed durable biosensors that can be printed directly onto clothing thus allow continuous biomedical monitoring outside hospitals. Read the story!

http://www.rsc.org/Publishing/ChemTech/Volume/2010/05/biosensors_in_briefs.asp