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

Carbon dots (CDs) are fluorescent carbon-based nanomaterials 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 for biological field due to 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 method and wavelength modulation strategy 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 current challenges and clinical prospects, aiming to deepen researchers' understanding and promote further advancements in this burgeoning field.