| In this paper,iron-based metal-organic frameworks composites with peroxidase activity were prepared with high catalytic activity towards H2O2.Based on that,combined with flow injection technology,the chemiluminescence aptasensor based on luminol-Na OH-H2O2 were constructed to detect?-fetoprotein,carcinoembryonic antigen and adenosine,respectively.The prepared aptasensor possessed high accuracy and high sensitivity.The first part,three kinds of iron-based MOFs(MIL-53(Fe),MIL-88B(Fe),MIL-100(Fe))were prepared with ferric ions as metal nodes and terephthalic acid as organic ligands.The prepared materials were characterized by scanning electron microscopy,Brunauer-Emmett-Teller,X-ray powder diffraction and other methods.Comparing with catalytic activity of MIL-53(Fe)and MIL-88B(Fe)and MIL-100(Fe),MIL-100(Fe)has the highest catalytic activity.Therefore,MIL-100(Fe)was applied as the signal amplification molecule.In addition,the adsorption capacity of MIL-100(Fe)to the aptamers was measured to be 6.0×10-10 mol/mg,and the adsorption time was 6 minutes.The positively charged MIL-100(Fe)were combined with negatively charged aptamers by electrostatic adsorption.As a result,a simple chemiluminescence sensing platform was constructed.In the presence of H2O2 and luminol,?-fetoprotein induced conformational changes of aptamers,thereby stimulating the production of chemiluminescence signal.Under the best conditions,the linear range of the sensor for detecting?-fetoprotein was 1.0×10-10 g/L-3.0×10-5 g/L.The detection limit was 7.7×10-11 g/L(3?).Meanwhile,the anti-interference ability,sensitivity stability of the sensor were acceptable.Besides,the analysis platform was successfully used to detect?-fetoprotein.The second part,hemin@MIL-88B(Fe)was prepared with ferric ion and hemin as the metal nodes and terephthalic acid as the organic ligand.Hemin@MIL-88B(Fe)was combined with carcinoembryonic antigen aptamer chain1 to form hemin@MIL-88B(Fe)-apt1.In addition,magnetic silica microspheres,magnetic carbon nanotubes and luminol-carcinoembryonic antigen aptamer chain2(L-apt2)were prepared.Scanning electron microscopy,ultraviolet,X-ray powder diffraction and other means were implemented to characterize the synthesized materials.The adsorption capacity of MCNTs to L-apt2 was5.0×10-11 mol/mg,and the adsorption time was 15 minutes.Therefore,Hemin@MIL-88B(Fe)was used as signal amplification molecule.Combined with flow injection chemiluminescence technology,Hemin@MIL-88B(Fe)was applied to construct a platform for detecting carcinoembryonic antigen.The linear range of the sensor was 0.01 ng/m L-100 ng/m L,and the detection limit was 1.5×10-3 ng/m L(3?).Besides,the selectivity of the sensor was acceptable.The third part,magnetic mesoporous silica microspheres(Fe3O4@m Si O2@n Si O2),MIL-101(Fe)were prepared with trivalent iron ions as the metal node and terephthalic acid as the organic ligand.MIL-101(Fe)was modified the DNA chain(S5)to obtain MIL-101(Fe)-S5.Luminol was loaded in Fe3O4@m Si O2@n Si O2,and adenosine-responsive DNA gel shell was formed outside Fe3O4@m Si O2@n Si O2 through the self-assembly of DNA strands(S1,S2,S3-Acry,S4-Acry,MIL-101(Fe)-S5).Transmission electron microscopy,infrared,X-ray powder diffraction and other means were applied to characterize synthesized materials.The loading amount of Fe3O4@m Si O2@n Si O2 to luminol was 1.12?mol/mg.MIL-101(Fe)was used to construct a flow injection chemiluminescence sensor for adenosine as signal amplification molecule technology.The linear range of the sensor was 1.00×10-10mol/L-1.00×10-6 mol/L,and the detection limit was 1.4×10-10 mol/L(3?).Besides,the repeatability,stability and selectivity of the sensor was acceptable. |
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