One of the first studies to examine dna mediated charge transport utilized covalently bound metallointercalators to explore long range quenching of luminescence by dna mediated electron transfer. Electrochemical studies of muty bound to a dna modified gold electrode demonstrate that the 4fe4s cluster of muty can be accessed in a dna mediated redox reaction. Without the support of my many mentors, colleagues, friends, and family this degree would not have been possible. Dna mediated electrochemistry is found to be effective for the tempo probe linked with an acetylene linker but not for a saturated tempo connected through an ethylenediamine linker. These data demonstrate that dna electrochemistry can be utilized to. Dnamediated electrochemistry of disulfides on graphite. Electrochemical studies of reaction of ciprofloxcin and dna. Distinct from conventional coppermediated click chemistry and ligasebased dna ligation, our approach is copper and enzymefree, making our method a simple and robust signal ampli. Pdf electrochemical processes involving selfassembled nanoparticles are currently the. Methylene blue mb, nile blue nb, and anthraquinone aq were covalently tethered to dna with three different covalent linkages.
Dna mediated reduction is exceptionally sensitive to even subtle perturbations to the intervening. Thermal and electrochemical gate effects on dna conductance. Thus disulfide reduction in the dna backbone appears to be dnamediated. Pdf electrochemistrybased sensors offer sensitivity, selectivity and low cost. The redox couples found show a strong ph dependence consistent with formation of a disulfide radical anion or 2e reduction of the disulfide to the two thiols.
Electrochemical sensing of attomolar mirna combining cascade. Dnamediated electrochemistry bioconjugate chemistry the base pair stack of dna has been demonstrated as a medium for longrange charge transport chemistry both in solution and at dnamodified surfaces. The base pair stack of dna has been demonstrated as a medium for longrange charge transport chemistry both in solution and at dna modified surfaces. Initial solution experiments featured photoinduced dnamediated ct between welldefined donor and acceptor sites 8, 9. A process of this kind can always be represented as a chemical reaction and is known generally as an electrode. Electrochemistry of dna monolayers modified with a. Electrochemistry at dna derivatized electrodes provides a valuable methodology to examine dna bound redox reactions and may offer new insight into dna mediated electron transfers. Dna modified electrochemistry shows that the 4fe4s cluster of dna bound ding, an atpdependent helicase that repairs rloops, is redoxactive at cellular potentials and atp hydrolysis increases. Electrocatalysis of ferricyanide reduction mediated by. Electrochemistry at dnaderivatized electrodes provides a valuable methodology to examine dnabound redox reactions and may offer new insight into dnamediated electron transfers. Dna duplexes are patterned onto the primary electrode array, while a secondary electrode array is used both to initiate dna monolayer formation and for electrochemical readout via dna mediated.
Electrically monitoring dna repair by photolyase pnas. On dna modified hopg, we examine the difference between a modified 3,4dehydrotempo moiety connected to the base pair stack via an acetylene linker and a saturated tempo connected via an ethylenediamine linker. Dna mediated electrochemistry is found to be effective for the tempo probe linked. Coupling into the base pair stack is necessary for dna. To increase the sensitivity of mismatch detection and further improve discrimination, mb was coupled to freely diffusing fe cn 63 in an electrocatalytic cycle figure 5. Citeseerx document details isaac councill, lee giles, pradeep teregowda. Both electrochemistry of dna interacting species and dna related electrocatalysis were shown to strongly depend on the dna surface coverage. Dna binding compounds 1, 5, quantum dots, and metallization 15, 16.
Pdf universal primers for the pcrmediated amplification. Intraduplex dnamediated electrochemistry of covalently. Dna electrochemistry and electrochemical sensors for. Pdf electrochemical behavior of selfassembled dnagold. Multiplexed electrochemistry of dnabound metalloproteins. Universal primers for the pcr mediated amplification of dna. Supporting information coupling into the base pair stack.
Electrochemical readout is accomplished through the measurement of current generated from a catalytic cycle. For the aq probe, dnamediated electrochemistry is found with an acetylene linker to uridine but not with an alkyl chain to the 5 terminus of the oligonucleotide. Related snp via dnamediated growth of silver nanoparticles on single walled carbon nanotubes jia tao,a,c, peng zhao,b, jing zheng,b, cuichen wu,b muling shi,b jishan li,b yinhui lib and ronghua yang a,b, aschool of chemistry and biological engineering, changsha university of. Dnamediated electrochemical reactions of fe4tmpypcl and. Here, multiplexed dna modified electrodes are used to i gain new insights on the electrochemical coupling of metalloproteins to the dna. Dnamediated electrochemistry is found to be effective for the tempo probe linked with an acetylene linker but not for a saturated tempo connected through an ethylenediamine linker. Barton division of chemistry and chemical engineering california institute of technology, pasadena, california 91125 to.
It has been proposed that longrange electron transfer between distally boundproteins in a dna mediated reaction may play a role in damage. While longrange ct was shown to yield oxidative damage in dna up to 200 a away from the bound oxidant 10, 11, dna ct. Handheld isothermal amplification and electrochemical. Dna modified gold electrodes have proven to be invaluable tools in both the study and the application of dna mediated charge transport ct chemistry 110. In these systems, the supramolecular selfassembly of thiolmodified dna duplexes on a gold surface yields well defined monolayers that can serve as platforms for electrochemical assays of dna ct. Dna electrochemistry and electrochemical sensors for nucleic. A onestep and labelfree, electrochemical dna detection using. Dna modified electrodes have been an essential tool for both gaining insights into the fundamental properties of dna and, due to the exquisite specificity of dna mediated charge. The inclusion of a single base mismatch in the dna duplex below the location of the disulfide leads to a significant attenuation in the electrochemical signal, while the inclusion of a mismatch above the disulfide has little effect on the electrochemistry observed. For analysis of targets with point mutation, after hybridization, due to the perturbation of the dna base stacking by the mismatched base pair, dna mediated charge transduction is interfered slinker et al. Dnamediated electrochemistry copyright permission to. This form of the probe has a reduced affinity for dna, destacking from the helix and entering solution.
Intraduplex dna mediated electrochemistry of covalently tethered redoxactive reporters. Initial solution experiments featured photoinduced dna mediated ct between welldefined donor and acceptor sites 8, 9. Jan 30, 2011 dna mediated electrochemistry through 100mer monolayers revealed large signals for wellmatched duplexes, comparable to those observed with shorter duplexes. It is examined via the use of electrochemical cells which are systems that incorporate a redox reaction to produce or utilize electrical energy. Most importantly i would like to thank my advisor, jackie, who has been an amazing mentor and role model over the years. This chemistry is exquisitely sensitive to structural perturbations in the base pair stack as occur with lesions, single base mismatches, and protein binding. Dna modified electrodes are extensively used in both the development of next generation diagnostic sensors 16 and the characterization of groundstate dna mediated electrochemistry 715. Thus disulfide reduction in the dna backbone appears to be dna mediated. Citeseerx multiplexed dnamediated electrochemistry. Isolated oxidation and reduction processes are not much good.
Although not detectable without dna, the redox potential of dna bound muty is. The electrochemistry of these labels when incorporated into dna has been examined in dna films containing both well matched and mismatched dna. Earlier we used dna mediated electrochemistry to characterize perturbations in the intervening dna structures using a well stacked probe, but here how well the probe is itself stacked serves as a specific. Intraduplex dna mediated reduction is established as a general mechanism for the reduction of distally bound stacked redoxactive species covalently tethered to dna through. Ourabilitytoaltertheredox states of these proteins in a dnamediated manner further suggests that dna may be a medium through which oxidation reduction reactions occur. Electrochemistry is the study of reactions in which charged particles ions or electrons cross the interface between two phases of matter, typically a metallic phase the electrode and a conductive solution, or electrolyte.
The electrochemistry of these molecules is studied as a function of ionic strength to determine the necessity of tight binding to dna and the number of electrons involved in the redox reaction. Nov 04, 2008 here, we discuss the characteristic features, applications, and advantages of dna mediated electrochemistry. Many different electrochemical reporters have been developed for dna modified electrodes, including. Electrochemical studies of muty bound to a dnamodified gold electrode demonstrate that the 4fe4s cluster of muty can be accessed in a dnamediated redox reaction. The mechanism of electron transfer to the 4fe4s cluster in endoiii was next investigated on both loosely and closely packed dsdnamodified electrodes. In this work, a dual amplified signal enhancement approach based on coupling deoxyribozyme dnazymedriven bipedal dna walkers bdw and terminal deoxynucleotidyl transferase tdt mediated dna elongation signal amplifications has been developed for highly sensitive and labelfree electrochemical detection of thrombin in human serums. Amperometric aptasensor for thrombin detection using enzyme mediated direct electrochemistry and dna based signal amplification strategy. Dnabased electrochemical sensors exploit a range of different chemistries, but.
Electrochemical monitoring of dnamediated charge transport processes. Surpassing the detection limit and accuracy of the. Oct 09, 20 intraduplex dna mediated reduction is established as a general mechanism for the reduction of distally bound stacked redoxactive species covalently tethered to dna through flexible alkane linkages. Mediated nanotetrahedron enhances the clearance of senescent cells aihua qu key lab of synthetic and biological colloids, ministry of education, international joint research laboratory for biointerface and biodetection, state key lab of food science and technology, school of food science and technology, jiangnan. A molecule associated with some monopartite begomoviruses. Here, we discuss the characteristic features, applications, and advantages of dnamediated electrochemistry. The base pair stack of dna has been demonstrated as a medium for longrange charge transport chemistry both in. Dna electrochemistry shows dnmt1 methyltransferase. These results support the application of dna modified hopg as a convenient and reproducible surface for electrochemical dna sensors using dna mediated charge transport. Dnamediated electrochemistry bioconjugate chemistry. Dna mediated electrochemistry through 100mer monolayers revealed large signals for wellmatched duplexes, comparable to those observed. In this work, taking this unique property of graphene in combination with the sensitive electrochemical transducer, we report a novel affinity mediated homogeneous electrochemical aptasensor using graphene modified glassy carbon electrode gce as the sensing platform.
A dna electrochemistry platform has been developed to probe proteins bound to. In this technique, an alkanethiolterminated, annealed duplex dna dsdna substrate is deposited on a. Left the bottom electrode modified with a dilute dna monolayer is responsible for generating electrochemical signals through dna mediated charge transport ct amplified by electrocatalysis. A signalon electrochemical biosensor based on dnazyme. Electrochemical sensing of attomolar mirna combining cascade strand displacement polymerization and reductant mediated amplification peng miao,ab abyiting jiang,ab atian zhang, yue huang,c and yuguo tang asuzhou institute of biomedical engineering and technology, chinese academy of sciences, suzhou 215163, p. Dna mediated electrochemistry bioconjugate chemistry this chemistry is exquisitely sensitive to structural perturbations in the base pair stack as occur with lesions, single base mismatches, and protein binding. Duplex dna 1 m was incubated with the redox active species 5 m in phosphate buffer. Electrochemistry using selfassembled dna monolayers on. Electrochemistry notes loudoun county public schools. Copperfree click chemistrymediated cyclic ligation. Intraduplex dna mediated electrochemistry of covalently tethered redoxactive reporters catrina g. Dnamediated electrochemical reactions of fe4tmpypcl.
Numerous approaches to electrochemical detection have been developed, including direct electrochemistry of dna, electrochemistry at polymermodified electrodes, electrochemistry of dna specific redox reporters, electrochemical amplifications with nanoparticles, and electrochemical devices based on dna mediated charge transport chemistry. To study the dna bound redox properties of enzymes with 4fe4s clusters, we used dna mediated electrochemistry, a robust method for directly measuring dna ct in the ground state 5, 31, 32 fig. Barton division of chemistry and chemical engineering, california institute of technology, pasadena, california 91125, usa abstract intraduplex dna mediated reduction is established as a general mechanism for the reduction of. Electrochemistry of dna monolayers gorodetsky group. Dna electrochemistry thus provides a first assay to characterize the redox chemistry of dna binding, and, significantly, to begin to determine whether these proteins may utilize dna mediated redox chemistry within the cell.
Thus the observed electrochemistry is dnamediated and a general characteristic of the dna, independent of the redox probe. Spectral characterization reveals a weakening of the plasmon coupling due to dna. The studies presented here once again highlight how sensitive dna mediated charge transport chemistry can be in reporting on dna structure. We developed a onestep and labelfree, electrochemical dna detection method using metal ionmediated molecular beacon mb probe specially designed to. Her unwavering belief in my capabilities helped me to become the scientist i am today. Coupling into the base pair stack is necessary for dna mediated electrochemistry alon a. Affinitymediated homogeneous electrochemical aptasensor on a. Even given this lower sensitivity toward dna, this current electrochemical method exhibits significantly lower levels of detection than obtainable by comparable uvvisiblebased methods 25, 28. The electrochemical behavior of ciprofloxacin cfx and its interaction with the. Although not detectable without dna, the redox potential of dnabound muty is. Dna binding shifts the redox potential of the transcription. Although dna is a promising material mechanically, it is important to understand the charge transport properties for both studies of dna in biological systems and the development of dna based materials. Amperometric aptasensor for thrombin detection using. Keywords electrochemical dna biosensors, hybridization, dnamediated electron transfer, electrochemical beacons, electrocatalytic sensors, redox indicators.
Sensitive, specific, and fast analysis of nucleic acids nas is strongly needed in medicine, environmental science, biodefence, and agriculture for the study of bacterial contamination of food and beverages and genetically modified organisms. Download pdf 4 mb abstract the aromatic core of double helical dna possesses the unique and remarkable ability to form a conduit for electrons to travel over exceptionally long molecular distances. Circulation tumor dna ctdna is an emerging biomarker for diagnosis and therapy of cancers. Gorodetsky, omar green, eylon yavin, and jacqueline k. Dna duplexes are patterned onto the primary electrode array, while a secondary electrode array is used both to initiate dna monolayer formation and for electrochemical readout via dnamediated. Finally, this dna mediated reduction of mb occurs primarily via intra rather than inter duplex intercalation, as probed through varying the proximity and integrity of the neighboring duplex dna. Multiplexed dnamediated electrochemistry caltechthesis. A process of this kind is known generally as an electrode process. The presence of the nonzero peak current for the mediated oxygen reduction at high concentrations of dna is also likely a result of the qz adsorption. Electrochemistry offers accurate, simple, inexpensive, and robust tools for the development of such analytical platforms that can successfully compete. This property makes it popular to prepare dna based optical sensors. We found that p58c binds dna tightly and is coupled into the duplex for redox activity in the oxidized state but is more loosely associated with the dna and redoxinactive in the.
Dna was evaluated for each studied electrode see experimental. In this cycle, dna mediated charge transport reduces an intercalative redox probe, methylene blue, to leucomethylene blue. Electrochemistry is the study of the relationship between chemical change and electrical work. Barton division of chemistry and chemical engineering, california institute of technology, pasadena, california 91125.
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