Preparation And Application Of Molecularly Imprinted Nano-Enhanced Solid-State Ru(bpy)₃²⁺ Electroluminescence Sensor

Electrochemiluminescence(ECL)sensing,which combines electrochemical and chemical luminescence,has become a powerful analytical method due to the simplicity,fast response,low background noise and excellent temporal and spatial control.Among various ECL emitters,tris(2,2?-bipyridine)ruthenium(II)(Ru(bpy)₃²⁺)is considered the most favorable ECL emitter because it has high luminescence efficiency,good electrochemical regeneration-ability and wide p H application range.However,the use of Ru(bpy)₃²⁺alone cannot meet a variety of analytical requirements,furthermore many substances have an effect on the ECL signal of Ru(bpy)₃²⁺.Nanomaterials have many excellent characteristics such as large specific surface area,strong electrical conductivity and good catalysis,thus they have huge potential in improving sensitivity and developing new ECL systems.Molecular imprinting is a technique to create molecularly imprinted polymers(MIP)with molecular recognition sites.MIP generally have good stability,reusability and low cost,and are widely combined with sensors to improve the selectivity.Herein,nanomaterials and MIP are introduced to the Ru(bpy)₃²⁺ECL system to improve the analytical performance of the ECL sensor.The main study contents are as follows:1.A three layer nanocomposite of Au NPs-silica dioxide-Ru(bpy)₃²⁺doped silica(Au@Si O₂@Ru DS)was synthesized for the first time and was successfully applied to fabricate a plasmon-enhanced ECL sensor for the highly sensitive detection of glutathione(GSH).Owing to the high luminescence efficiency of Ru DS and the surface plasmon resonance of Au NPs,the resulting sensor showed wide linear response ranges(1.0 f M–1.0 n M and 1.0 n M–1.0?M)and low detection limit(0.5 f M,S/N=3)for GSH detection.2.Polyethyleneimine(PEI)capped Cd S quantum dots(PEI-Cd S QDs)were synthesized and used as coreactant for the first time.They were combined with Au@Si O₂@Ru DS nanocomposite to construct a novel self-enhanced ECL platform.Then,a creatinine imprinted poly(o-aminophenol)film was prepared on its surface by electropolymerization to fabricate a MIP-ECL sensor.A good linear range of 0.05 n M to 5?M and a detection limit of 0.02 n M for creatinine sensing were achieved.The sensor was applied to detect creatinine in human serum and urine samples,and the results were in good agreement with those of commercial enzyme-linked immunosorbent assay kit.3.To overcome the influence of of instrumental or environmental change,a novel potential-resolved ratiometric ECL sensor,using Ru(bpy)₃²⁺doped Ti O₂nanoparticles(Ti O₂-Ru(bpy)₃²⁺NPs)with PEI-Cd S QDs as new ECL emitter unit and MIP as recognition element,was proposed for the detection of sialic acid.The sensor exhibited high sensitivity,selectivity and stability.Under the optimized conditions,the linear range was 1.0 n M–0.1 m M and the detection limit was low to 0.017 n M(S/N=3).Its good practical feasibility was confirmed by detecting sialic acid in human serum and bird's nest samples with satisfactory results.