Nanosensors optically selective

Optically Selective Nanosensors for Trace-Level Toxic Ions... 

Kopelman et al.73 have prepared fiber optic sensors that are selective for nitric oxide and do not respond to most potential interferents. Both micro-and nanosensors have been prepared, and their response is fast (<1 s), reversible, and linear up to 1 mM concentrations of nitric oxide. The respective "chemistry" at the fiber tip was contacted with the sample, light was guided to the sample through the microfiber, and emitted light was collected by a microscope (without the use of fibers, however). 

Some bead materials possess porous structure and, therefore, have very high surface to volume ratio. The examples include silica-gel, controlled pore glass, and zeolite beads. These inorganic materials are made use of to design gas sensors. Indicators are usually adsorbed on the surface and the beads are then dispersed in a permeation-selective membrane (usually silicone rubbers). Such sensors possess high sensitivity to oxygen and a fast response in the gas phase but can be rather slow in the aqueous phase since the gas contained in the pores needs to be exchanged. Porous polymeric materials are rarer and have not been used so far in optical nanosensors. 

Baker SLR, Kopelman R, Meyer TE, Cusanovich MA (1998) Fiber optic nitric oxide selective biosensors and nanosensors. Anal Chem 70 971-976... 

In this chapter we have defined the key factors for the development of receptors as indicator dyes , and surface-confined nanomaterials as carriers , for the creation of optical chemical sensors capable of selectively discriminating trace levels of toxic analytes. Our aim was to widen the knowledge base with regards to the causes of- and solutions to - metal-ion toxicity. A key factor when designing optical nanosensors to sense mercury, cadmium, lead and antimony is the stable immo-... 

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