Synergetic Surface Enhancement of Quantum Dots-Based Electrochemiluminescence with Photonic Crystal Light Scattering and Metal Surface Plasmon Resonance for Sensitive Bioanalysis

Abstract

Noble metal nanostructures and photonic crystals (PhCs) have been widely investigated as the substrates for the construction of surface enhanced electrochemiluminescence (SE-ECL) biosensors due to the surface plasmon resonance (SPR) and light scattering effect. However, challenges still existed, such as limited enhanced intensity for SPR and the incomplete mechanism for photonic enhancement effect. Besides, in most detection scenarios with trace target, weak signal responses often accompanied which called for high detection performances. Hence, it is extremely urgent to further explore the enhanced mechanism and develop SE-ECL strategy with better signal enhanced capability and higher signal detection sensitivity for sensitive bioanalysis.Here, a synergistically SE-ECL strategy was developed for sensitive determination of prostate specific antigen (PSA) protein. The randomly arranged PS spheres and PS PhC arrays was applied to enhance the ECL emission of CdS quantum dots (QDs) and the results suggested that the PhC arrays displayed superior intensity (0.22) than the r-PS interface (0.10). Gold nanoparticles (Au NPs) were introduced onto the two kinds of surface and further boosted the ECL intensity. According to the ECL measurements, Au NPs modified at the r-PS surface exhibited only slight increase (0.13) while the PhC arrays showed approximately 5-fold enhancement (0.92) benefited on the synergistically enhancement. The finite-difference time-domain (FDTD) simulation indicated that the ECL enhancement was ascribed to the coupled electromagnetic (EM) field at the surface of PS PhCs and Au NPs. The SE-ECL could achieve the detection range from 1 pg/mL to 1μg/mL and detection limit of 0.41 pg/mL (S/N=3).The PhC arrays and metal surface plasmon nanostructure was firstly combined for synergetic enhancement in the SE-ECL biosensors for bioanalysis. The enhancement mechanism of the SE-ECL strategy was deeply discussed which opened a new venue for the rational design of the advanced SE-ECL biosensors. A synergistically enhanced platform was constructed with high sensitivity which showed great perspective for clinical diagnosis.

Keywords: electrochemiluminescence, photonic crystal, surface plasmon resonance, prostate specific antigen, synergetic surface enhancement