Resonance light scattering technique for sensitive detection of heparin using plasmonic Cu_2-xSe nanoparticles

Heparin (Hep) is a mucopolysaccharide sulfate anticoagulant drug widely used in clinic and thus the quantification of Hep concentration is of great significance. In this work, a simple resonance light scattering (RLS) method for the determination of Hep concentration using plasmonic copper selenide nanoparticles (Cu_2-xSe NPs) was developed. The positively-charged Cu_2-xSe NPs capped by cetyltrimethyl ammonium bromide (CTAB) were aggregated by negatively-charged Hep, consequently inducing a significant enhancement in the RLS signals of plasmonic Cu_2-xSe NPs. Under the optimal reaction conditions, the increased RLS intensity is linearly correlated with the concentrations of Hep in the range of 0.01-0.60 μg mL^-1 (R² = 0.999), with a low detection limit (LOD) of 4.0 ng mL^-1 (3σ). This method offered a simple, sensitive and selective strategy for determining Hep, which can be further successfully applied to quantify Hep in the heparin sodium injection.