A highly-enhanced electrochemiluminescence luminophore generated by a metal–organic framework-linked perylene derivative and its application for ractopamine assay

Abstract

In this study, a sensitive and effective monitoring method for ractopamine (RAC) was developed based on a sensitive electrochemiluminescence (ECL) aptasensor. Here, we employed a perylene derivative (PTC-PEI) with a Cu-based metal–organic framework (HKUST-1), which could accelerate the electron-transfer (ET) rate and strengthen interactions by the amido bond, resulting in enhanced ECL sensitivity and stability. Astonishingly, compared with the response of PTC-PEI and complex, the ECL signal of the MOF-based ECL material was noticeably raised by 6 times higher than that of PTC-PEI. HKUST-1 exhibited an excellent catalytic effect towards the electrochemical reduction process of S₂O₈²⁻, thus allowing more sulfate radical anions (SO₄˙⁻) to be generated. The strong ECL intensity of HKUST-1/PTC-PEI not only stemmed from the fixation of PTC-PEI that utilized its excellent film-forming abilities but also originated from the high porosity of HKUST-1 that carried more luminophores able to be excited. Satisfyingly, in the presence of the target molecule RAC, we observed an obvious quenching effect of signal, which could be attributed to aptamer recognition resulting in RAC being specifically captured on the electrode. Under optimal conditions, the developed sensor for the RAC assay displayed a desired linear range of 1.0 × 10⁻¹²–1.0 × 10⁻⁶ M and a low detection limit of 6.17 × 10⁻¹³ M (S/N = 3). This ECL sensor showed high sensitivity, good stability and excellent selectivity. More importantly, the proposed aptasensor exhibited excellent determination towards RAC detection and potential practical utility for real samples.