Ascorbic Acid-Loaded Apoferritin-Assisted Carbon Dot-MnO₂ Nanocomposites for the Selective and Sensitive Detection of Trypsin

A novel “turn-on” fluorescent trypsin detection platform dependant on carbon dot-MnO₂ (CD-MnO₂) nanocomposites and ascorbic acid-loaded apoferritin (APOAA) was fabricated. The detection mechanism relied on trypsin-catalyzed enzymolysis of APOAA, which released ascorbic acid (AA) as a reducing agent to disintegrate the MnO₂ nanosheets, causing the recovery of the fluorescence of CDs. An excellent performance and high sensitivity of trypsin determination were observed with a detection limit (LOD) of 0.3411 ng/mL. This work provides us with a unique strategy for trypsin detection in human serum samples, which reveals the potential applications in clinical detection.