Carbon dots (CDs): basics, recent potential biomedical applications, challenges, and future perspectives

From the commencement of this century, the emerging fluorescent carbon dots (CDs)—the new member of the carbonaceous nanomaterial family—have stimulated significant attention worldwide due to their inimitable advantages such as non-blinking strong fluorescence emission, low cost, facile synthesis methods, good physicochemical properties, good water solubility, low toxicity, high chemical and photo stability, and tunable photoluminescence. CDs have provided a promising platform for biological, environmental, and energy-related applications such as bioimaging, biosensing, medical diagnosis, catalysis, multicolor light-emitting diode production, phototherapy, drug and gene delivery, food safety, and energy conversion owing to their innovative and fascinating multifunctional properties together with excellent biocompatibility and environmental friendliness. This mini review aims to present a comprehensive framework of the unique advantages and up-to-date advanced biomedical applications of CDs to date, and to place special emphasis on the recent progress in phototherapy, and drug and gene delivery. Besides the applications, an overview of CDs along with some important methodologies of synthesis are also discussed herewith. Lastly, the key issues to be challenged and perspectives for the future development of CDs in the field of biomedical sector are highlighted in this article which will help give valuable insights into new research directions.