Recent Advances in Near-Infrared II-Emitting Carbon Dots for Ultrasensitive Detection of Disease-Related Biomarkers

Carbon dots (CDs) have emerged as widely used functional nanomaterials in biomedical sensing due to their tunable fluorescence emission wavelength, excellent biocompatibility, and ease of functional modification. Fluorescent CDs operating in the near-infrared region II (NIR-II, 1000–1700 nm) offer advantages such as deep tissue penetration, low tissue autofluorescence background, and a high imaging signal-to-noise ratio, making them widely used in the detection of disease biomarkers. This article systematically reviews the latest research progress of NIR-II CDs in the detection of disease-related biomarkers. Firstly, we summarize the classification of fluorescent CDs and two types of chemical synthesis strategies. Subsequently, the research progress of NIR-II CDs in the detection of disease-related physiological markers is reviewed, and the fluorescence biosensing mechanism of NIR-II CDs is analyzed in depth. Finally, we explore the advantages of NIR-II fluorescent CDs in disease diagnosis and molecular imaging, analyze their current key challenges, and provide insights into their future development directions. This review aims to garner increased attention for the development of a new generation of high-performance NIR-II fluorescent CD biosensors.