Rapid detection of heparin by gold nanorods and near-infrared fluorophore ensemble based platform via nanometal surface energy transfer

As a mucopolysaccharide sulfate anticoagulant drug, heparin plays important roles in clinic. In this work, heparin was analyzed based on the nanometal surface energy transfer (NSET) between gold nanorods (AuNRs) and tetrakis (4-sulfophenyl) porphyrin (TPPS4) fluorescent molecules. The results showed that AuNRs could bind TPPS4 by electrostatic interaction and coordination to quench its fluorescence. While heparin was able to bind AuNRs with a stronger electrostatic interaction to compel TPPS4 to leave AuNRs surface, leading to the fluorescence recovery of TPPS4, which was proportional to the concentration of heparin in a range of 0.05∼2 μg/mL with the detection limit as low as 6.7 ng/mL (3σ). Based on this, a NSET platform for the analysis of trace heparin sodium was proposed with fast response, high sensitivity and excellent specificity, which was successfully applied to the detection of heparin in injection with the satisfactory result. Importantly, the NSET mechanism was fully discussed.