The Construction And Application Of Electrochemiluminescence Immunosensor Based On Metal-organic Framework

Metal organic frameworks?MOF?are widely used owing to their porosity and large specific surface area,structural and functional diversity,and unsaturated metal sites.By regulating the chemical composition to regulate the function,their ordered crystal pores form providing more active sites in the MOF structure.The easy diffusion and multi-channel properties of the molecules also make them widely used in the field of catalysis.Electrochemiluminescence?ECL?is a powerful analytical technique with a wide linear range and a simple background.Due to its fast detection speed,high sensitivity and cost saving,it has become an important method for in vitro diagnosis and detection.Luminol as a luminescent substance is an important electroluminescent system.As nanomaterials?such as carbon nanotubes and metal nanoparticles?have high specific surface area and good electrical conductivity,they are often used as signal amplification platforms in biosensors.Until now,it has been reported that luminol reduced Au or Ag nanoparticles to enhance ECL luminescence and further used to detect bio-molecules.The key point of this paper is to enhance the electrochemiluminescence by using cobalt-ion-rich MOFs material.In this paper,two works were carried out to prepare a cobalt-nickel ultra-thin nanosheet structural material and a cobalt-based dodecahedral MOF material,which were respectively combined with luminol-Ag NPs to utilize its higher electrochemistry.After building the label-free immunosensor,the change of ECL signals are used to detect ?-fetoprotein?AFP?and cardiac troponin I?c Tn I?.The main contents are as the following:1)Co/Ni ultra-thin nanosheets enhance ECL and its application in detecting AFPIn this experiment,we synthesized a cobalt-nickel ultra-thin nanosheet and mixed it with luminol-reduced Ag nanoparticles to detect electrochemiluminescence.According to the ICP measurement,we found that the ECL of ultra-thin sheet structure is greatly improved compared to the cobalt ions or nickel ions due to its large specific surface area.After constructing a label-free immunosensor,the ECL system was used to detect the tumor marker ?-fetoprotein.With good selectivity,stability and reproducibility,it shows that the MOF structure can be well applied in the field of electrochemiluminescence and has broad application prospects.2)Cobalt-based MOF enhances ECL and its application in detecting c Tn IIn the design of this experiment,a Co²⁺-rich metal-organic framework?ZIF-67?was selected as a nanocarrier-catalyzed luminol reduced Ag nanoparticle composite?Luminol-Ag NPs?.It is worth noting that the compounded ZIF-67@Luminol-Ag NPs exhibited extremely highier ECL performance compared to Luminol-Ag NPs,enhanced about two orders of magnitude.In order to explore the reasons for the enhanced performance,we compared the ZIF-8 with similar morphology and found out that the hollow skeleton structure of MOF and catalytic oxidation of cobalt ions enhanced ECL synergistically.Ultimately,a label-free ECL immunosensor was constructed for the detection of cardiac troponin I which as the main marker of myocardial infarction.In our research,the mechanism,selectivity,sensitivity,stability and repeatability of the sensing method had been studied and the immunosensor had low detection limit.Such satisfactory performance can not only broaden the scope of application of MOF,but also provides a new way to detect myocardial infarction.