21-03-2012, 01:46 PM
Sensor
Nanosensors.ppt (Size: 10.19 MB / Downloads: 226)
A sensor is an instrument that responds to a physical stimulus (such as heat, light, sound, pressure, magnetism, or motion)
It collects and measures data regarding some property of a phenomenon, object, or material
Sensors are an important part to any measurement and automation application
The sensor is responsible for converting some type of physical phenomenon into a quantity measurable by a data acquisition (DAQ) system
Why Nanosensors
Particles that are smaller than the characteristic lengths associated with the specific phenomena often display new chemistry and new physics that lead to new properties that depend on size
When the size of the structure is decreased, surface to volume ratio increases considerably and the surface phenomena predominate over the chemistry and physics in the bulk
The reduction in the size of the sensing part and/or the transducer in a sensor is important in order to better miniaturise the devices
Science of nano materials deals with new phenomena, and new sensor devices are being built that take advantage of these phenomena
Sensitivity can increase due to better conduction properties, the limits of detection can be lower, very small quantities of samples can be analysed, direct detection is possible without using labels, and some reagents can be eliminated.
Size and compatibility
Nano sensors deliver real-time information about the antibodies to antigens, cell receptors to their glands, and DNA and RNA to nucleic acid with a complimentary sequence
Sensitivity of the conventional biosensors is in the range between 103 and
104 colony forming units (CFU)/ml. The dimensional compatibility of nanostructured materials renders nanotechnology as an obvious choice derived from its ability to detect ~ 1 CFU/ml sensitivity