Rapid laboratory diagnosis of Wilson’s disease: One-step simultaneous detection of exchangeable copper and ceruloplasmin in serum based on nanotechnology

Abstract Monitoring the level of exchangeable copper (CuEXC) and ceruloplasmin (Cp) in serum is of great significance for Wilson’s disease (WD). In this work, a facile one-step competitive immunoassay for rapid and simultaneous detection of CuEXC and Cp has been developed based on antigens coated magnetic nanoparticles (immuno-MNPs) and antibodies functionalized quantum dots (QDs-Abs). Just by mixing immuno-MNPs, with diluted serum and QDs-Abs together, the antigens on immuno-MNPs compete with the target in serum and bind to QDs-Abs, thereby causing the changes in fluorescence intensity of QDs. Under selected conditions, this one-step method exhibited excellent precision and selectivity with the measured limit of detection of 0.2 nM and 7.0 μg/L for CuEXC and Cp, respectively. Most importantly, this method was successfully applied to detect CuEXC and Cp without the usual time-consuming pretreatment. The results showed no significant difference ( P >0.01) from those of ICP-AES and ELISA; moreover, CuEXC significantly decreased to a normal level after the treatment of preliminarily diagnosed WD patients, while the changes of Cp level is not significant ( P  > 0.01). Therefore, the proposed one-step competitive immunoassay has great potential applications in the rapid laboratory diagnosis of WD with distinct advantages over the existing methods in terms of multi-target, accuracy, facile, fast and cost-effectiveness.