Advanced synthesis and biomedical applications of colloidal quantum dots: Innovations in Imaging, drug delivery, and theranostics

Colloidal quantum dots (CQDs) are semiconductor nanoparticles with unusual optical and electrical characteristics due to quantum confinement effects, and hence are versatile in a number of applications. One characteristic that has been of utmost interest is their great tunability in light emission by size and composition, especially in applications for cancer therapy and biomedicine. The recent success of hot-injection, heat-up, and microwave-assisted syntheses of QDs has enabled better control in the size, shape, and surface chemistry of QDs, leading to their performance improvement in bioimaging, drug delivery, and photodynamic therapy. In cancer therapy, QDs are applied to targeted drug delivery and imaging enhancement because of their superior brightness and resistance to photodegradation. However, there are some other significant challenges, such as biocompatibility and toxicity issues linked to heavy metals in some QDs. Research is now evolving both safer, more biocompatible QDs and ways to target them for precision in treatment. The development of synthesis methods will continue with regard to quantum dots and will play an important role in the combination of diagnostic and therapeutic functions on one platform—advancing theranostics within integrated cancer therapy.