Sensitive Fluorescent Determination of Matrix Metalloproteinase-2 (MMP-2) Using the Inner Filter Effect (IFE) with Carbon Dots and Aggregated Gold Nanoparticles

Matrix metalloproteinase-2 (MMP-2) is a key biomarker involved in various pathological processes, so its sensitive and selective detection is of great clinical significance. A fluorescent sensor for the detection of MMP-2 was successfully designed based on the inner filter effect (IFE) between carbon dots (CDs) and gold nanoparticles (AuNPs). In the presence of MMP-2, peptide chains are hydrolyzed, releasing short peptides that contain thiol groups and positive charges, thereby inducing the aggregation of AuNPs. This aggregation disrupts the IFE between AuNPs and CDs, leading to a significant enhancement of the fluorescence. By monitoring the change in fluorescence intensity of CDs, the concentration of MMP-2 was accurately determined. The sensor exhibited a linear response across the concentration range from 1.0 to 150 ng/mL, with a detection limit as low as 0.23 ng/mL, which is lower than those of previously reported methods. Furthermore, the sensor demonstrated minimal interference from coexisting biochemical substances for MMP-2 in human serum. Notably, the sensor was successfully applied to determine MMP-2 in human serum, showing satisfactory recovery rates ranging from 98.8 to 1106.0%. In conclusion, this fluorescent sensor offers high selectivity and sensitivity for MMP-2 detection, making it a promising tool for clinical diagnosis of related diseases.