Carcinoembryonic antigen (CEA) is the most widely adopted biomarker for the early determination of various cancers, thus it is very important to design a simple and highly effective sensing method to detect CEA. Herein, by synthesizing Fe-MOF nanohybrid loaded with platinum nanoparticles (Pt NPs/Fe-MOF) nanozyme and selecting CEA aptamer (Apt) as the specific recognition element, a simple nanozyme-based voltammetric sensor was designed to detect CEA based on Apt-controlled the catalytic activity of Pt NPs/Fe-MOF nanozyme. The as-synthesized Pt NPs/Fe-MOF nanozyme could catalyze effectively 1,2-diaminobenzene oxidation to produce electroactive 2,3-diaminophenazinc (DAP) which can exhibit a strong reduction current. Nonetheless, when Pt NPs/Fe-MOF is covered fully by Apt of CEA, the peroxidase activity of the as-synthesized Pt NPs/Fe-MOF nanozyme is remarkably restricted and the peak current of DAP would disappear nearly. Interestingly, this catalytic activity could be recovered effectively in the presence of CEA owing to the specific identification of Apt toward CEA. Through optimizing several experimental factors, the as-designed nanozyme voltammetric sensor offers superior detective performance for CEA. In addition, the as-designed sensor possesses superior specificity and selectivity, reproducibility and stability as well as practical applications, showing great potentials for achieving simple, sensitive and highly effective determination of CEA.
Zijing Xu,Dalan Jin,Xiaoyi Lu,Yonglun Zhang,Weilu Liu
Ovalbumin (OVA) is the main allergen in vaccines, and the sensitive detection of it could protect hypersensitive people. However, traditional detection technologies usually require natural antibodies, natural enzymes and long analysis time, which is not conducive to transportation, preservation and rapid detection. To solve this problem, the sandwich colorimetric strategy using Ni-Fe-MOF nanozyme linked with magnetic silicon dioxide surface molecularly imprinted particles (MSi-MIPs) are proposed for the first time to rapidly detect OVA in vaccines. The high sensitivity of this strategy depends on the sandwich structure of surface molecularly imprinted nanoparticles, OVA and nanozymes. Ultra-thin Ni-Fe-MOF nanozyme exhibits large specific surface area and more peroxidase active sites. This has enabled the establishment of a specific and stable detection tool for OVA in vaccines. Under the optimal conditions, the assay exhibited a wide linear response range of 2.5 to 25 ng mL −1 . The low limit of detection (1.02 ng mL −1 ) and the short analysis time (20 min) demonstrated the great potential of the strategy for OVA detection in vaccine samples.
The development of simple, efficient and low-cost methods for rapid on-site monitoring have always been a challenging topic in the field of analysis. Here, we successfully constructed a selective, sensitive and rapid colorimetric sensor for the sensing of diethylstilbestrol (DES) by using molecular imprinting technology to construct specific recognition sites on the surface of Fe-based metal organic frameworks (Fe-MOF) peroxidase-like nanozyme. The surface of obtained sensor (Fe-MOF@MIP) had abundant channels and imprinted cavities that allowed the substrate to enter and responded with Fe-MOF core to drive the chromogenic reaction of 3,3′,5,5′-tetramethylbenzidine (TMB). When DES was present, it could specifically enter the cavities and obstruct the channels of substrate into the Fe-MOF core, thereby inhibiting the chromogenic reaction. The experimental results demonstrate that the sensor had excellent selectivity, anti-interference and catalytic stability. In the linear range of 0 – 1.67 μ M, the detection limit is as low as 8.43 nM, which is superior to peer sensors. To better adapt to in-situ analysis, we have further developed a rapid analysis method based on photo colorimetry, which performed well in real sample analysis and recovery test with the results consistent with the gas chromatograph-mass spectrometer (GC–MS), demonstrating its great potential for rapid on-site monitoring.
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