| Electrochemiluminescence(ECL)sensor is an effective analysis method for trace target analysis(10-4 M to 10-10 M).Compared with Raman analysis,electrochemistry analysis and photoelectric analysis,electrochemiluminescence exhibits the advantages of low background signal,high sensitivity,and stability,due to the high efficiency and stability of electrons in the valence band transition.It has been widely used in the analysis of trace biomarkers.Ru(bpy)32+is an electrochemiluminescence material with low toxicity and is widely used in electrochemiluminescence.However,due to its characteristics such as good water solubility and unstable luminescence,the used of Ru(bpy)32+was limited in electrochemistry.In this paper,Ru(bpy)32+is compounded with polyvinylimide,metal organic framework polymer(metal-organic frameworks,MOF)and other nanomaterials to prepare electroluminescent nanocomposites with high stability,high luminous efficiency and good biocompatibility material.Since the low concentration of the target substance in biological system,it is not conducive to the early diagnosis and detection of the disease.Therefore,strategies such as molecular imprinting and DNA enzyme cycle amplification have been applied to the detection of target substances by electrochemiluminescence sensors.The main contents of this paper are as follows:1.“Signal-on”molecularly imprinting-aptamer electrochemiluminescence platform for ultrasensitive detection of thrombinThrombin is closely related to human thrombotic diseases,and the detection of thrombin is of great significance to the diagnosis and treatment of related diseases.In this paper,an ultra-sensitive ECL sensing platform that combines ECL“signal-on”and molecular imprinting strategies is prepared.Combining the“signal-on”ECL sensing strategy and molecular imprinting technology for the first time,the nanocavity corresponding to thrombin produced by molecular imprinting can be used with specific aptamers(TBA1,TBA2)for multiple specific recognition of thrombin.When the Ru NP/PEI-GO nanocomposite recognizes thrombin through specific aptamer2(TBA2),the system will generate ECL signal,indicating the presence of thrombin in the detection system.In addition,the ECL nanocomposite material(Ru NP/PEI-GO)with high luminous efficiency was synthesized by using Ru(bpy)32+/polyvinylimide(PEI)-graphene oxide(GO),which is compared with Ru(bpy)32+,the luminous intensity of Ru NP/PEI-GO is about seven times that of the original.Introducing PEI as a co-reactant into the nanocomposite material greatly shortens the electron transmission path of the ECL system,thereby reducing energy loss and significantly improving the efficiency and stability of ECL.The Ru NP/PEI-GO nanocomposite material greatly improves the performance of ECL,thereby further improving the sensitivity of the sensing platform.Satisfactorily,the new TB detection ECL sensing platform exhibits outstanding sensitivity,with a minimum detection limit of only 28.73f M in the thrombin concentration range of 10-13 M to 10-8 M.Therefore,the developed“signal-on”ECL platform with self-reinforced Ru NP/PEI-GO nanocomposites are expected to become an effective tool for detecting other biomarkers in the future.2.ECL ultrasensitive sensing platform based on Hg2+,Ag+induced allosteric switch and alternative target DNA amplification for multiple targetsHeavy metals in the human body can interact strongly with proteins and enzymes,causing them to lose their activity.They may also accumulate in certain organs of the human body,causing chronic poisoning.Therefore,the detection and toxicity assessment of heavy metals are of great significance.Herein,an unlabeled“ON-OFF”electrochemiluminescence(ECL)sensor based on simple DNA target conversion and novel Ru-MOF material was successfully constructed for ultrasensitive detection of Hg2+,Ag+.First,m DNA which rich with Cytosine(C)and Thymine(T)will mismatch in the presence of Hg2+or Ag+to form T-Hg2+-T complex or C-Ag+-C complex,which in turn causes m DNA to form hairpin DNA.With the help of phi29 and Nt.Bbv CI,a large amount of t DNA is generated.The t DNA will open the G base-rich hairpin H1that was fixed on the surface of Ru-MOF.Finally,t DNA hybridized with the opened H1 and forms a special G-quadruplex conjoined structure.Therefore,in the presence of the t DNA,the formed G-quadruplex can capture the hemin in solution,which ultimately reduces the ECL signal of Ru-MOF.After continuous strand displacement amplification(SDA),the obtained t DNA can be combined with a large amount of H1,thereby further amplifying the electrochemical sensing signal changes.The detection limits of this ECL sensor for Hg2+and Ag+are as low as 0.32 f M and 2.98 f M,and the dynamic response ranges from 1.0 f M to 1 n M and 10 f M to 10 n M,which is much more powerful than most reported ECL sensors for multi-ion detection.Furthermore,the real samples were also desirably analyzed,indicating that the proposed strategy is an ideal platform for the fabrication of versatile DNA biosensors.3.Based on new multifunctional signal material:Ru-MOF and Pd/Cu2O double quenching system for ultrasensitive detection of prostate antigen(PSA)Nowadays,electrochemiluminescence immunosensor with the unique advantages of adjustable luminescence and ultra-high sensitivity has become one of the most promising immunoassay techniques,especially for the analysis of low-concentration biomarkers.In this article,an ECL resonance energy transfer strategy based on protein biological activity protection was developed.This method uses Ru-MOF as a new low-potential ECL luminophor(donor)and Pd/Cu2O as a quenching probe(acceptor).Specifically,firstly,Ru(bpy)32+functionalized metal-organic framework(MOF,Metal Organic Framework)film was prepared in one step using a self-assembly method assisted by an electrochemical method.In this strategy,Ru(bpy)32+is used as an electrochemiluminescence(ECL)probe and structure directing agent,trimellitic acid(H3btc)is used as a ligand,and Zn(NO3)2 is used as a source of Zn2+,using electrochemical driving The synergistic reaction enables MOF to be synthesized in one step,and MOF is synthesized and deposited on the electrode surface at the same time.Because many Ru(bpy)32+molecules are encapsulated in the frame,the Ru-MOF film as a sensing platform shows excellent PEC and PEC behavior.When it coexists with the K2S2O8 cathode,it will generate a strong ECL signal at a low potential of-1.15 V(vs Ag/Ag Cl),and a strong PEC signal can be generated under a certain light intensity.When the target prostate antigen(PSA)enters the detection system and is captured by the primary antibody,the very low electron transport ability of PSA itself significantly reduces the PEC signal.The double quencher form of Cu2O-coated Pd shell-core nanostructure(Pd/Cu2O)enhances the quenching effect of Pd.When the Pd/Cu2O and PSA are connected with the secondary antibody,the modified electrode forms a stable and firmly believed immune structure,ECL signal is weakened.The photocurrent signal of the sensor has a good linear relationship with the PSA concentration in the range of 5 ng m L-1-150 ng m L-1,the LOD is 0.16 ng m L-1.The ECL signal of the sensor has a good linear relationship with the PSA concentration in the range of 50 pg m L-1-5?g m L-1,and the detection limit is 17.83 pg m L-1.Importantly,this work not only uses the promising dual-signal Ru-MOF to construct a biosensing platform,but also has great potential in the detection of biomarkers for disease diagnosis and clinical analysis. |
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