Effectively detect enoxaparin using polymyxin B as medium through fluorescent strategy based on carbon dots with antioxidant activity

Low molecular weight heparin (LMWH) plays an important role in the prevention and treatment of venous thromboembolism. Sensitive and facile monitoring of LMWH is of great significance for clinical special populations. Herein, using enoxaparin (Enox) as the typical representative of LMWH, a convenient and accurate fluorescence method was developed for Enox detection using carbon dots with antioxidant activity (A-CDs) as probe and polymyxin B (PMB) as medium agent. Compared with the simple Enox or PMB, the formed complex of PMB and Enox (PMB-Enox) based on the electrostatic interaction exhibited a new absorbance peak at 340 nm. Correspondingly, the absorbance of PMB-Enox overlapped with the exciting wavelength of A-CDs at 350 nm and effectively quenched the fluorescence of A-CDs through inner filter effect (IFE). The decreased fluorescence intensities of A-CDs were controlled by the increased Enox with constant PMB. A linear fitting equation was obtained between the quenching efficiency (QE) of A-CDs and variable contents of Enox in the range of 0.8–25.0 μg/mL. And the limit of detection (LOD) was 0.64 μg/mL. The recovery of the injection of Enox in human plasma was acceptable with rational relative standard deviations. Moreover, this fluorescence sensing strategy possesses the prospect of developing reliable pharmaceutical analysis method based on the consideration of drug’s property and pharmacological action and the controllable design of fluorescence probes.