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Quantum dots are nanoplatforms made from semiconductor materials as they possess tunable “quantum size effects.” Approximately, 1000 to 100000 atoms are present in the quantum dots due to which they are classified neither as an extended solid structure or single molecular entity. The properties of quantum dots that can be tuned by controlling the size and composition of particles are brightness of the spectrum, photo- and chemical stability of particles, width of emission spectrum, etc. [53]. Fluorescence and FRET-based biosensors used for ultrasensitive detection of biomolecules like acids, enzymes, sugars, antibodies, and antigens are generally synthesized using quantum dot [71]. These particles are generally fabricated from elements of Group II (e.g., Zn, Cd), VI (e.g., Se, S), III–V, and IV–VI of the periodic table. The quantum dots can be synthesized by heating/combustion method, hydrothermal technique, microwave/ultrasonic-assisted method, electrochemical synthesis, acid oxidation, arc discharge, laser ablation, and plasma treatment [46]. The application of quantum dots in drug delivery is limited due to inherent toxicity of cadmium and lead present in these particles. Despite formulation of Cd- and Pb-free quantum dots, not much decrease in the toxicity has been observed.