Ultrasensitive electrochemiluminescence immunosensor based on gold-functionalised NiFe layered double hydroxide and...

Electrochemiluminescence (ECL) technology has become an essential analytical methodology in biomolecular detection, attaining both profound research advancements and extensive practical applications in this domain. Herein, we used carboxylated mesoporous silica (MSN-COOH) as a container to encapsulate Tris(2,2-bipyridyl)ruthenium(II)²⁺ (Ru(bpy)₃²⁺)-a luminophore-in its pores to achieve enrichment (RuMSN). The reactive intermediates Ru(bpy)₃³⁺ and TPrA^•+ are attracted by the electro-negative carboxyl group on the MSN-COOH surface, substantially reducing the reaction distance and improving the ECL response efficiency. The flower-like NiFe layered double hydroxide (NiFe-LDH) nanostructure possesses significantly high specific surface area and good electrocatalytic performance, while gold nanoparticles also demonstrate excellent electrical conductivity and biocompatibility. To enhance sensor sensitivity, gold nanoparticles were loaded onto the NiFe-LDH surface forming the Au@NiFe-LDH composite, which improves performance by enhancing conductive properties and increasing antigen-antibody binding sites. This study established a sandwich-configuration electrochemiluminescence detection platform capable of highly sensitive PSA analysis.The biosensor demonstrated excellent stability, specificity and selectivity, with a linear detection range of 0.1 pg/mL-50 ng/mL and a detection limit as low as 63 fg/mL (S/N = 3). This confirms the clinical application value of the detection system in the early screening of prostate cancer.