ABSTRACT
Quantum dots (QDs) are semiconductor nanomaterials with diameters ranging between 2 and 10 nm that are characterized by a broadband excitation wavelength and narrow emission wavelength. They emit size-dependent bright fluorescence that is very resistant to photo- bleaching. The nanotechnology industry is receiving a lot of attention in the development of novel sensing systems, as well as in the enhancement of the performance of bioanalytical assays. The surface modification of the QD surface involves prior conversion from the organic-soluble form into the water-soluble form. Ligand exchange is one of the methods by which the surfaces of QDs are modified to make them water-soluble in preparation for nanobiosensor development. A ligand can be an ion, atom, molecule, or functional group forming a complex with QDs that results in an interface between the core QDs or core/shell and the surroundings. The surface modification of the QD surface involves prior conversion from the organic-soluble form into the water-soluble form.
