Sensors & Transducers Journal, Vol. 113, Issue 2, February 2010, pp. 1-17
processes over long time scales, which is a unique property. A review on QD biosensors was reported earlier by Sapsford et al. .
It has been found that single QD incorporated nanosensors for DNA detection can reduce significantly or even eliminate the complication of background fluorescence encountered by conventional molecular fluorescence resonance energy transfer (FRET) technique . Zhang, et al.  reported the extraordinary performance characteristics of a QD-FRET nanosensor for DNA detection with ultrahigh sensitivity, discrimination capacity and great simplicity. Fig. 2 shows how FRET induced QD DNA nanosensor works. Tran, et al.  described in their paper how CdSe-ZnS QDs can be designed and used as nanosensors for detection both in water soluble and in solid phase conditions using Förster energy transfer method.
Fig. 2. Schematic of single QD-based DNA nanosensors: a) Conceptual scheme showing the formation of a nanosensor assembly in the presence of targets; b) Fluorescence emission from Cy5 on illumination on QD caused by FRET between Cy5 acceptors and QD donor in a nanosensor assembly; c) Experimental setup [Source: Ref. 35].
Quantum dot technology presents a promising tool in neuroscience research . Several researchers are trying hard to produce new quantum-dot-based tools for applications to neurobiology. Triller, et al.  used antibody functionalized quantum dots to study diffusion of glycine receptors in cultures of primary spinal cord neurons. Vu et al.  tagged nerve growth factor to quantum dots and used them to promote neuronal-like differentiation in cultured pheochromocytoma 12 (PC12) cells. This method could be used to visualize and track functional responses in neurons. A technique of producing biocompatible water-soluble quantum dot micelles that retain the optical properties of individual quantum dots, was developed by Brinker, et al. . Ting, et al.  developed a modified quantum dot labeling approach that presented the relatively large size of antibody–quantum-dot conjugates and the instability of some quantum-dot–ligand interactions. The problems with semiconductor QDs are its toxic effects, which prevent it from being used in-vivo applications.