Near-infrared carbon dots: Pioneering emerging frontiers in biomedical applications

Carbon dots (CDs) are fluorescent carbon-based nanomaterials with sizes smaller than 10 nm, renowned for their exceptional properties, including superior anti-photobleaching, excellent biocompatibility, and minimal toxicity, which have garnered significant interest. Near-infrared (NIR) light has emerged as ideal light source for biological field due to its advantages like minimal light scattering and absorption, long wavelength emission, enhanced tissue penetration, and reduced interference from biological backgrounds. Notably, CDs exhibiting efficient absorption and/or emission characteristics in the NIR spectrum have demonstrated remarkable promise in the biomedical arena. This study provides a comprehensive overview of the preparation methods and wavelength modulation strategies for near-infrared CDs (NIR-CDs). It also systematically reviews the research progress of NIR-CDs in the areas of biosensing, bioimaging, and therapy. Additionally, it discusses the current challenges and clinical prospects, aiming to deepen researchers' understanding and promote further advancements in this burgeoning field.