Research On Electrochemical And Electrochemiluminescent Sensing Based On Novel Porphyrin Materials

Porphyrin and its derivatives have a variety of types and structures.They also have the special physiological activity,good biological compatibility,attractive photoelectric properties,catalytic activity,oxygen transfer and molecular recognition,which make them in many fields have a wide application.Especially,the development of novel porphyrins materials and further application to construct efficient chemical sensors have attracted more attention.In the field of electrochemical and electrochemiluminescent sensors,the development of new electrochemical or electrochemiluminescent signal probes to improve the sensitivity of the sensor is always the frontier.Therefore,based on the excellent properties of porphyrin,a novel electrochemical dual-signal probe and four kinds of porphyrins electrochemiluminescent luminophors were prepared successfully by using iron porphyrins hemin and 5,10,15,20-tetra(4-carboxyphenyl)porphyrins as raw materials under the condition of less organic solvents and synthesis steps.The new porphyrin materials were investigated by electrochemical,electrochemiluminescent method,morphology and spectroscopy technology.Combined with a series of nanomaterials and nucleic acid signal amplification strategies,the prepared porphyrin materials were used to construct innovative chemical sensors.The heavy metal ions,drug molecules and biological macromolecules were chose as model targets to investigated the application of the sensors.The ideal experimental results demonstrated that this work provides a new idea and highlight the significance of porphyrin materials in sensing applications.The research of this paper is mainly carried out in the following five parts:1.Engineering DNAzyme cyclic amplification integrated dual-signal electrochemical sensing system for specific recognition of histidine enantiomersA novel label-free dual-signal amplifying“on-off-on”electrochemical biosensor has been designed for specific recognition of histidine(His)enantiomers.The remarkable dual-signal is provided by engineering His-dependent DNAzyme and the Fe₃O₄nanoparticles attached reduced graphene oxide nanocomposite(Fe₃O₄@r GO)as enzymatically magnified selector and electroactive indicator,respectively.In this strategy,L-histidine(L-His)cyclically catalyzes the cleavage of the substrate sequences,leading to the release of rich G-quadruplex and enzymatic sequences.The released enzymatic sequences sequentially trigger the additional cleavage cycle,the G-quadruplex forming sequences associate with hemin to form G-quadruplex/hemin structures,which act as label-free NADH oxidase to generate significantly amplified current for sensitive detection of L-His.Whereas no obvious response is observed after the DNAzyme cascade assay reacted with D-His.Combined the merits of His-dependent DNAzyme amplifying electrochemical response and the dual-signal generated by the new electroactive materials,the developed assay for the detection of His enantiomers demonstrate excellent selectivity and sensitivity.2.Multifunctional zinc oxide promotes electrochemiluminescence of porphyrin aggregates for ultrasensitive detection of copper ionThe design and exploration of highly efficient organic luminophores for an electrochemiluminescence(ECL)sensor is a fascinating and promising subject.Herein,we present a surfactant-assisted self-assembly of 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin(TCPP)J-aggregate as a robust organic luminophore to construct the solid-state ECL sensing platform with significantly enhanced and constantly stable signals,by using peroxydisulfate(S₂O₈^2-)as the coreactant,and L-cysteine capped zinc oxide nanoflowers(Zn O@Cys NFs)as the multifunctional energy donor and coreactant accelerator.Compared with TCPP monomer,this TCPP J-aggregate possesses a unique aggregation-induced electrochemiluminescence(AIECL)performance,which results in 5-fold enhancement in red-light ECL emission at 675 nm.The resonance energy transfer from the Zn O@Cys NFs(energy donor)to the TCPP J-aggregate(energy acceptor)substantially improves the ECL intensity and stability.Zn O@Cys NFs have also been used as a coreactant accelerator to promote the conversion of more S₂O₈^2-into SO₄^·-.The corresponding ECL mechanism has been investigated by UV-vis absorption spectrum,photoluminescence,ECL,and density functional theory.Since L-cysteine on Zn O@Cys NFs can efficiently realize bidentate chelation with Cu²⁺,the proposed ECL sensor shows a highly selective and sensitive quenching effect for the detection of Cu²⁺with a wide linear range from 1.0 pmol·L^-1to 500 nmol·L^-1and a detection limit of 0.33 pmol·L^-1,paving a bright research direction for the development of TCPP aggregates in ECL field.3.Eu-porphyrin functionalized coordination polymer nanoflowers:rational design of high performance electrochemiluminescence emitter for mucin 1 sensingThe electrochemiluminescence(ECL)biosensors in detecting low-abundance biomarkers of diseases still are highly desirable for meeting tunable luminescence and ultrahigh sensitivity.However,the use of biotoxic emitter and high potential-dependent ECL response limits its application.Herein,a functionalized and novel europium porphyrin based microporous coordination polymer(Eu-PCP)nanoflowers was subtly synthesized by a one-step solvothermal method.Specifically,the benign Eu-PCP was first showed a stronger and more stable ECL emission at low-potential in aqueous phase as comparison with TCPP monomers,which has a 7.7 times and 4.6times enhanced ECL intensity and efficiency.The ECL spectra of Eu-PCP at 673 nm was observed,confirming an obvious red-light emission.Considering the unique ECL characteristic of Eu-PCP,an exonuclease III(Exo III)-assisted recycling amplification ECL biosensor was constructed for mucin1 ultrasensitive detection utilizing Eu-PCP as satisfying emitter,Ce O₂as the coreactant accelerator and Mn O₂@Au as the quenching probe.The proposed biosensor exhibited a low limit of detection(0.32 fg·m L^-1,S/N=3)in the linear range from 1.0 fg·m L^-1to 10.0 ng·m L^-1.The Eu-PCP not only explored a universal and promising strategy to design and synthesize high-performance coordination polymer as a promising ECL emitter,but also had momentous potential in bioanalysis.4.Achieving synergistically enhanced dual-mode electrochemiluminescent and electrochemical drug sensors via a multi-effect porphyrin-based metal-organic frameworkSince the sensing methods in drug detection are commonly hampered by signal capacity limitations and sole analysis information,dual-mode sensors with high accuracy and flexibility have become more popular.Herein,we present a two-dimensional porphyrin-based metal-organic framework(Zn TCPP MOF)as a unique electrochemiluminescent(ECL)and electrochemical(EC)dual-signal indicator,combined with L-penicillamine-capped Au nanoparticles(L-Pen-Au NPs)as a specific selector,to construct an innovative dual-mode drug sensing platform.Inspired by the optical and electrocatalytic activity of 5,10,15,20-tetrakis-(4-carboxyphenyl)porphyrin(TCPP),a series of Zn TCPP MOFs have been synthesized through a facile bottom-up method.Among them,the“oval-like”Zn TCPP MOF generates higher ECL responses than TCPP monomer when acting as a near-infrared luminophore and outputs stronger EC signals when acting as a redox active probe.In addition,the Zn TCPP MOF,when employed as a nanocarrier,can load many L-Pen-Au NPs.Using L-Pen-Au NPs as selectors,synergistically enhanced dual-mode sensors for detection of the anti-inflammatory drug S-naproxen(S-NAP)exhibit versatile and superior performance and a wide linear range with an ultralow limit of detection.We believe that the applications of this dual-mode sensor can be readily expanded to become a universal platform for sensitive detection of different types of drugs by changing the selector.5.Three kinds of porphyrin dots as novel electrochemiluminescence luminophores:facile synthesis and biosensingExploring novel electrochemiluminescence(ECL)luminophores with highly efficient and benign is strongly anticipated for ECL evolution.Here,three kinds of porphyrin dots including5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin(TCPP)dots,Zn TCPP dots and TCPP-based metal organic framework(Zn TCPP MOF)dots have been subtly synthesized for the first time by a universal straightforward exfoliation of bulk porphyrin aggregates or Zn TCPP MOF.These as-designed porphyrin dots give excellent annihilation ECL activity,also exhibit stable and robust cathodic or anodic ECL properties with different coreactants in aqueous phase.Especially,the ECL efficiency of three kinds of porphyrin dots in S₂O₈^2-cathodic system are 56,44,39-fold higher than that of Ru(bpy)₃²⁺standard,respectively.As a new type of ECL luminophores,TCPP dots coupled with a lead ion-specific DNAzyme and hybridization chain reaction cycle amplification are used to fabricate a label free“signal-on”ECL biosensor for ultrasensitive detection of Pb²⁺.A wide detection ranges from 10 pmol·L^-1to 1?mol·L^-1with a low limit of detection(1.2 pmol·L^-1)is obtained.These porphyrin dots provide evidence for the use of organics-based dots as new ECL luminophores for fundamental ECL research,and highlight the significance of small-sized organic nanomaterials in ECL sensing applications.