Biosense Of Adamantanes And Intracellular MicroRNA Based On Gold Nanoprobes

This paper focused on the construction of functional gold nanoprobes.A colloidal gold paper-based biosensor was constructed based on the antigen-antibody immune response.Based on the specific recognition of the oligonucleotide aptamer and the targets,the gold nanorods dimer was assembled in a controllable way.We focused on its plasmon resonance,plasma chiroptical activity,surface-enhanced Raman scattering and other optical characteristics,then the self-assembled gold nanorods dimer-based ultra-sensitive biosensor was constructed.Through the construction of these biosensors,rapid simultaneous detection of five amantadine drug residues in animal food and quantitative detection of intracellular biomarkers with high specificity were realized.Firstly,the two haptens of amantadine drugs were designed and synthesized,and monoclonal antibodies capable of simultaneously identifying five amantadine drugs were obtained,whose subtype was IgG_2b.The corresponding immunological conjugate of amantadinehaptenisamantadine-hapten-BSA,andthecoatedantigenis amantadine-hapten-OVA.The affinity constant(K_aff)of monoclonal antibody was 7.25×10⁹L/mol,and the IC₅₀ values of amantadine,rimantadine,surimantadine,1-amantadine methyl ketone,1-amantadine methanol were 0.88 ng/mL,0.43 ng/mL,0.39 ng/mL,7.81 ng/mL and7.42 ng/mL,respectively.Secondly,a colloidal gold chromatographic strip based on monoclonal antibody labeled with spherical gold nanoparticles was established to detect 5 amantadines at the same time.The recovery efficiency of amantadine was 101.4%-110.5%,that of amantadine was101.9%-106.7%,that of amantadine was 101.9%-106.7%,that of 1-amantadine methanol was89.4%-100.4%,and that of 1-amantadine methyl ketone was 91.5%-99.0%.Thirdly,the gold nanorods can be induced to form side by side dimers with a certain angle between them through the specific recognition of ssDNA and targets.At the same time,the fluorescence dye molecules and Raman beacon molecules were modified at the end of the ssDNA.With the increase of the concentration of the targets,the yield of gold nanorods dimer increased,and the CD,SERS and fluorescence signals changed correspondingly.Fourthly,on the foundation of the concentration of targets in living cells and the changes of circular dichroism,surface enhanced Raman scattering and the fluorescence intensity,we developed a sensitive biological sensor that can detect several signals at the same time.The CD signal was dominant,the surface enhanced Raman scattering and fluorescence signal were supplementary.And the in situ detection of miRNA-21 was successfully implemented in living cells,and the detection limit was 0.081 fmol/10?g_RNA.The biosensor based on side by side dimers of gold nanorods was applied to HeLa and PCS-460-010 cell lines,which proved the universality of this ultra-sensitive detection method.