Ultra-sensitive Electrochemiluminescence Platform Based on Magnetic Metal-Organic Framework for the Highly Efficient Enrichment

In this work, an original magnetic ECL platform with remarkable electrochemiluminescence (ECL) performance was proposed which based on the co-growth of the CdSnS nanocrystallines (NCs) and UiO-66-NH2 on the surface of the magnetic metal-organic framework (MMOF). Herein, the carboxyl groups (-COOH) CdSnS NCs participated in the further growth of MMOF and formed octahedron-shaped MMOF@CdSnS nanoparticles, this strategy prevented the aggregation of CdSnS NCs and resulted in an excellent ECL emission intensity, which could be applied as the promising ECL tag. Besides, the MMOF@CdSnS nanoparticles exhibited superior superparamagnetism that achieved outstanding performance in magnetic enrichment. Due to these advantages, the proposed ECL platform was applied in detecting alpha-fetoprotein (AFP) as an example. Under optimized conditions, the ECL response was decreased as the concentration of AFP increased that followed a good linear relationship from 1 fg/mL to 100 ng/mL with an ultra-low detection limit of 0.2 fg/mL (S/N = 3). With favorable sensitivity, specificity and reproducibility, the proposed sensing platform was firstly introduced in ECL bioanalysis, which broadened the applications of MMOF and created a new method in enhancing the ECL intensity. This work demonstrated the strategy that MMOF-immobilized CdSnS NCs nanocomposite which was further magnetic enriched shed light on new way in ECL detection.