A novel self-enhanced electrochemiluminescence sensor based on PEI-CdS/Au@SiO2@RuDS and molecularly imprinted polymer for the highly sensitive detection of creatinine

In this work, a novel self-enhanced solid state electrochemiluminescence (ECL) platform, based on polyethyleneimine (PEI) capped CdS quantum dots (PEI-CdS QDs) as coreactant and Au@SiO2@Ru(bpy)3(2+) doped silica (Au@SiO2@RuDS) nanocomposite as ECL emitter, was constructed. The PEI-CdS QDs integrated double coreactant of PEI and CdS QDs, thus significantly promoted the ECL of Au@SiO2@RuDS. Polyaniline hydrogel was introduced to boost the electron transfer and to improve the immobilization of PEI-CdS/Au@SiO2@RuDS. In addition, creatinine imprinted poly(o-aminophenol) film was electrodeposited on the PEI-CdS/Au@SiO2@RuDS surface as recognition element. Thus, the obtained sensor possessed high sensitivity, stability, reproducibility and selectivity for creatinine sensing. The change of ECL intensity and logarithm of creatinine concentration showed a good linear relationship in the range of 0.05 nM to 5 mu M, and the detection limit was low to 0.02 nM. 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.