Highly selective fluorometric detection of streptokinase via fibrinolytic release of photoluminescent carbon dots integrated into fibrin clot network

Abstract

This work pioneers a selective fluorometric assay for the fibrinolytic agent streptokinase by strategically coupling its thrombolytic action to fluorescence signaling using carbon dots integrated into fibrin clot network. Streptokinase triggers clot lysis and caused release of photoluminescent carbon dots integrated within the fibrin network in a concentration-dependent manner. Transmission electron microscope (TEM) imaging verifies distinct aggregation of the carbon dots upon addition to fibrin. The carbon dots are derived via an eco-friendly hydrothermal approach using cucumber peel as the source of carbon. Structural and optical characterization of the carbon dots were performed using different techniques including X-ray diffraction, TEM, Fourier-transform infrared spectroscopy, and ultraviolet–visible absorption and fluorescence spectroscopies. All experimental parameters influencing the formation of the fibrin clot and factors governing the release of carbon dots upon the addition of streptokinase have been fully optimized. This fluorescence assay offers high selectivity for streptokinase over potential interferences in addition to excellent sensitivity with a 0.017 μg/mL limit of detection and a wide linear range (0.05–500 μg/mL). Successful application to pharmaceutical formulations is demonstrated with excellent recovery and precision. By ingeniously linking streptokinase activity to carbon dot fluorescence, this novel assay provides a rapid, simple and eco-friendly method for selective streptokinase detection.