Quantum Dots (QDs), whose diameters are often limited to 10 nm, have been of interest to
researchers for their unique optical characteristics, which are attributed to quantum confinement.
Following their early application in the electrical industry as light-emitting diode materials, semiconductor
nanocrystals have continued to show great potential in clinical diagnosis and biomedical applications.
The conventional physical and chemical pathways for QD syntheses typically require
harsh conditions and hazardous reagents, and these products encounter non-hydrophilic problems due
to organic capping ligands when they enter the physiological environment. The natural reducing abilities
of living organisms, especially microbes, are then exploited to prepare QDs from available metal
precursors. Low-cost and eco-friendly biosynthesis approaches have the potential for further biomedical
applications which benefit from the good biocompatibility of protein-coated QDs. The surface
biomass offers many binding sites to modify substances or target ligands, therefore achieving
multiple functions through simple and efficient operations. Biosynthetic QDs could function as bioimaging
and biolabeling agents because of their luminescence properties similar to those of chemical
QDs. In addition, extensive research has been carried out on the antibacterial activity, metal ion detection
and bioremediation. As a result, this review details the advanced progress of biomedical applications
of biosynthesized QDs and illustrates these principles as clearly as possible.