Carbon Dots: Synthesis, Characterization, and Applications in the Detection of Bilirubin - Recent Advances and Challenges.

Bilirubin (BR) is a yellow tetrapyrrole compound present in digestive juice, formed from the breakdown of hemoglobin (Hb). Normal serum bilirubin levels range from 0.30 to 1.20 mg/dL. Elevated BR levels act as a crucial biomarker for diagnosing and managing liver diseases, underscoring the importance of its accurate measurement. In recent decades, carbon dots (CDs) have garnered significant attention for their exceptional properties, including strong compatibility and ease of synthesis. These attributes have driven extensive research into developing highly efficient CD-based probes for the rapid and selective detection of bilirubin. This review presents a thorough introduction to CDs and bilirubin metabolism, systematically categorizes the synthetic methodologies for CDs, outlines key characterization techniques, and critically analyzes various sensing approaches, including fluorescence-based and colorimetric sensors. Furthermore, it discusses current challenges and highlights potential future research directions to advance the development of high-performance CDs and enhance bilirubin detection technologies.