Semiconducting quantum dots: Modification and applications in biomedical science

Semiconductor quantum dots (SQDs) have received much attention due to their high quantum yield (QY), tunable emission spectrum, and excellent photostability. These unique optical properties endow SQDs with excellent biomedical application prospects, including biomedical imaging, drug delivery, clinical diagnosis, photodynamic therapy, DNA hybridization, and RNA profiling. This review introduces the classification of QDs and provides a brief description of the characteristics of QDs under each classification. Taking the type II B-VI A QDs as an example, inorganic and organic modification methods, and the corresponding advantages and disadvantages are summarized and discussed. Controlled modification approaches make them exhibit different functions in the bioimaging and drug delivery fields. The typical or classic instances are also listed to present the highlights of the applications of SQDs in the biomedical field. Based on these, this review raises a variety of possible challenges and perspectives of SQDs in biomedical applications in the future.