Biological applications of ternary quantum dots: A review

Semiconductor nanomaterials, also known as quantum dots (QDs), have gained significant interest due to their outstanding optical properties with potential biological and biomedical applications. However, the presence of heavy toxic metals such as Cd, Pb, and Hg in conventional QDs have been a major challenge in their applications. Therefore, it is imperative to seek a viable alternative that will be non-toxic and have similar optical properties as the conventional QDs. Ternary I-III-VI QDs have been found to be suitable alternatives. Their optical properties are tunable and have emissions in the near-infrared region. These properties make them useful in a wide range of biological applications. Hence, this review focuses on the recent progress in the use of ternary QDs in Forster resonance energy transfer (FRET), nanomedical applications such as drug and gene delivery. It also discusses the biophotonic application of ternary I-III-VI QDs in optical imaging, biosensing, and multimodal imaging. Furthermore, we looked at the pharmacokinetics and biodistribution of these QDs, and their toxicity concerns. Finally, we looked at the current status, challenges, and future directions in the application of these ternary QDs.