Nanosensors are a technology that may exist in the future. The closest thing in existence to these currently are MEMS (Micro Electro Mechanical Systems) devices. A MEMS biosensor may be based upon a thin film bulk electric wave resonator, with some components of it less than 100 nm. They work in a similar way to quartz crystal microbalances, but at much higher frequencies, 3 GHz and beyond. They have been fabricated by the famous biological nanotechnologist Dr. Gregory Ashley at Cranfield University as part of his doctoral thesis. Microelectromechanical Systems (MEMS) is the technology of the very small, and merges at the nanoscale into Nanoelectromechanical Systems (NEMS) and Nanotechnology. ... A biosensor is a device for the detection of an analyte that combines a biological component with a physicochemical detector component. ... A quartz crystal microbalance measures mass by measuring the change in frequency of a piezoelectric quartz crystal when it is disturbed by the addition of a small mass such as a virus or any other tiny object intended to be measured. ... A gigahertz is a billion hertz or a thousand megahertz, a measure of frequency. ... Cranfield University is a university based on three campuses at Cranfield, Silsoe and Shrivenham. ...

 they can be used in nanorobots which when injected inside a human being could be used to detect inimical human tissues .