“…Various approaches for qualitative as well as quantitative analysis of these bioanalytes have been developed, mainly based on electroanalytical techniques, , high-performance liquid chromatography (HPLC), , capillary electrophoresis separation, immunoassays based on derivatization with fluorescent/phosphorescent reagents, spectrophotometric methods, etc. , Unfortunately, all of these methods require either expensive reagents or equipment or skilled manpower to ensure reproducibility. In this context, much attention is being paid to the development of simple and cheap fluorescent probes, without compromising selectivity and sensitivity. − Nanoparticles have been proven to be an efficient substitute for organic fluorophores, particularly for developing emission “turn on/off” sensors. − Among various nanoparticles, quantum dots (QDs) are of particular interest in developing novel biosensors owing to their unique properties such as broad absorption band, emission in the visible region, photostability, etc. − Moreover, the potential of QDs to transfer electrons or holes to biologically important molecules, interacting covalently or noncovalently with their surface, can be used to tune the QD emission intensity and thus generate charge transfer-based emission “on/off” signaling. − …”