Quantum dots for biomedical innovation: overview, applications, and biosafety

Quantum dots (QDs), a class of versatile semiconductor nanomaterials, have emerged as revolutionary tools in biomedical research due to their unique optical properties, tunable surface chemistry, and biocompatibility. This review provides a systematic overview of the fundamental characteristics of QDs, encompassing their diverse types, quantum confinement effects, photostability, synthesis strategies, and advanced characterization techniques. We discuss the cytotoxicity mechanisms of QDs and highlight surface functionalization strategies for enhancing the biocompatibility and targeting efficiency. Through precise functionalization and surface engineering, QDs have successfully been tailored for a wide array of biomedical applications, including cellular imaging, drug delivery, and single-virus tracking. However, their potential biosafety remains a paramount concern, as toxicity profiles are highly dependent on the chemical composition, particle size, and surface modifications. A key focus of this review is on recent breakthroughs in QDs-based single-virus tracking, which provides a robust framework for optimizing QDs platforms in virology research and therapeutic development. We also address the major challenges in clinical translation, such as insufficient targeting accuracy, protein corona formation, immune recognition, and scalable manufacturing. Finally, we discuss the biosafety considerations and future perspectives for the clinical translation of QDs technologies, addressing key challenges including long-term fate, regulatory hurdles, and the development of heavy-metal-free alternatives.