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Chiorcea-Paquim AM. Electrochemical Sensing of Curcumin: A Review. Antioxidants (Basel) 2023; 12:2029. [PMID: 38136149 PMCID: PMC10740878 DOI: 10.3390/antiox12122029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/09/2023] [Accepted: 11/12/2023] [Indexed: 12/24/2023] Open
Abstract
Curcumin is a natural polyphenol derived from turmeric (Curcuma longa) root that has been used for centuries as a spice, coloring agent, and medicine. Curcumin presents anti-inflammatory, antioxidant, anticarcinogenic, antimicrobial, antiviral, antimalarial, hepatoprotective, thrombosuppressive, cardiovascular, hypoglycemic, antiarthritic, and anti-neurodegenerative properties. It scavenges different forms of free radicals and acts on transcription factors, growth factors and their receptors, cytokines, enzymes, and genes, regulating cell proliferation and apoptosis. Curcumin is electroactive, and a relationship between its electron transfer properties and radical-scavenging activity has been highlighted. The objective of this review is to provide a comprehensive overview of the curcumin electron transfer reactions, with emphasis on the controversial aspects related to its oxidation mechanism. The final sections will focus on the electroanalysis of curcumin in natural products, highlighting the most important sensing strategies, based on functional electrodes and nanostructured materials, essential for the development of more efficient in vitro methods of detection and quantification of curcumin in food samples, supplements, and nutripharmaceuticals.
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Affiliation(s)
- Ana-Maria Chiorcea-Paquim
- Instituto Pedro Nunes (IPN), 3030-199 Coimbra, Portugal;
- University of Coimbra, Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Advanced Production and Intelligent Systems (ARISE), Department of Chemistry, 3004-535 Coimbra, Portugal
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Abstract
Flavonoids represent a large group of aromatic amino acids that are extensively disseminated in plants. More than six thousand different flavonoids have been isolated and identified. They are important components of the human diet, presenting a broad spectrum of health benefits, including antibacterial, antiviral, antimicrobial, antineoplastic, anti-mutagenic, anti-inflammatory, anti-allergic, immunomodulatory, vasodilatory and cardioprotective properties. They are now considered indispensable compounds in the healthcare, food, pharmaceutical, cosmetic and biotechnology industries. All flavonoids are electroactive, and a relationship between their electron-transfer properties and radical-scavenging activity has been highlighted. This review seeks to provide a comprehensive overview concerning the electron-transfer reactions in flavonoids, from the point of view of their in-vitro antioxidant mode of action. Flavonoid redox behavior is related to the oxidation of the phenolic hydroxy groups present in their structures. The fundamental principles concerning the redox behavior of flavonoids will be described, and the phenol moiety oxidation pathways and the effect of substituents and experimental conditions on flavonoid electrochemical behavior will be discussed. The final sections will focus on the electroanalysis of flavonoids in natural products and their identification in highly complex matrixes, such as fruits, vegetables, beverages, food supplements, pharmaceutical compounds and human body fluids, relevant for food quality control, nutrition, and healthcare research.
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Affiliation(s)
- Ana-Maria Chiorcea-Paquim
- Instituto Pedro Nunes (IPN), 3030-199 Coimbra, Portugal;
- University of Coimbra, Centre for Mechanical Engineering, Materials and Processes (CEMMPRE), Advanced Production and Intelligent Systems (ARISE), Department of Chemistry, 3004-535 Coimbra, Portugal
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Chiorcea-Paquim AM. Advances in Electrochemical Biosensor Technologies for the Detection of Nucleic Acid Breast Cancer Biomarkers. Sensors (Basel) 2023; 23:4128. [PMID: 37112468 PMCID: PMC10145521 DOI: 10.3390/s23084128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/03/2023] [Accepted: 04/11/2023] [Indexed: 06/19/2023]
Abstract
Breast cancer is the second leading cause of cancer deaths in women worldwide; therefore, there is an increased need for the discovery, development, optimization, and quantification of diagnostic biomarkers that can improve the disease diagnosis, prognosis, and therapeutic outcome. Circulating cell-free nucleic acids biomarkers such as microRNAs (miRNAs) and breast cancer susceptibility gene 1 (BRCA1) allow the characterization of the genetic features and screening breast cancer patients. Electrochemical biosensors offer excellent platforms for the detection of breast cancer biomarkers due to their high sensitivity and selectivity, low cost, use of small analyte volumes, and easy miniaturization. In this context, this article provides an exhaustive review concerning the electrochemical methods of characterization and quantification of different miRNAs and BRCA1 breast cancer biomarkers using electrochemical DNA biosensors based on the detection of hybridization events between a DNA or peptide nucleic acid probe and the target nucleic acid sequence. The fabrication approaches, the biosensors architectures, the signal amplification strategies, the detection techniques, and the key performance parameters, such as the linearity range and the limit of detection, were discussed.
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Affiliation(s)
- Ana-Maria Chiorcea-Paquim
- University of Coimbra, CEMMPRE, ARISE, Department of Chemistry, 3004-535 Coimbra, Portugal;
- Instituto Pedro Nunes, 3030-199 Coimbra, Portugal
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Chiorcea-Paquim AM, Oliveira-Brett AM. Electrochemistry of chemotherapeutic alkylating agents and their interaction with DNA. J Pharm Biomed Anal 2022; 222:115036. [DOI: 10.1016/j.jpba.2022.115036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 09/06/2022] [Accepted: 09/07/2022] [Indexed: 10/14/2022]
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Chiorcea-Paquim AM, Enache TA, De Souza Gil E, Oliveira-Brett AM. Natural phenolic antioxidants electrochemistry: Towards a new food science methodology. Compr Rev Food Sci Food Saf 2020; 19:1680-1726. [PMID: 33337087 DOI: 10.1111/1541-4337.12566] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 03/26/2020] [Accepted: 03/31/2020] [Indexed: 11/27/2022]
Abstract
Natural phenolic compounds are abundant in the vegetable kingdom, occurring mainly as secondary metabolites in a wide variety of chemical structures. Around 10,000 different plant phenolic derivatives have been isolated and identified. This review provides an exhaustive overview concerning the electron transfer reactions in natural polyphenols, from the point of view of their in vitro antioxidant and/or pro-oxidant mode of action, as well as their identification in highly complex matrixes, for example, fruits, vegetables, wine, food supplements, relevant for food quality control, nutrition, and health research. The accurate assessment of polyphenols' redox behavior is essential, and the application of the electrochemical methods in routine quality control of natural products and foods, where the polyphenols antioxidant activity needs to be quantified in vitro, is of the utmost importance. The phenol moiety oxidation pathways and the effect of substituents and experimental conditions on their electrochemical behavior will be reviewed. The fundamental principles concerning the redox behavior of natural polyphenols, specifically flavonoids and other benzopyran derivatives, phenolic acids and ester derivatives, quinones, lignins, tannins, lignans, essential oils, stilbenes, curcuminoids, and chalcones, will be described. The final sections will focus on the electroanalysis of phenolic antioxidants in natural products and the electroanalytical evaluation of in vitro total antioxidant capacity.
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Affiliation(s)
| | - Teodor Adrian Enache
- CEMMPRE, Department of Chemistry, University of Coimbra, Coimbra, 3004-535, Portugal
| | - Eric De Souza Gil
- CEMMPRE, Department of Chemistry, University of Coimbra, Coimbra, 3004-535, Portugal.,Faculdade de Farmácia, Universidade Federal de Goiás, Setor Universitário, Goiânia, Goiás, Brasil
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Fernandes IG, Chiorcea-Paquim AM, Oliveira-Brett AM. Calcium channel blocker lercanidipine electrochemistry using a carbon black-modified glassy carbon electrode. Anal Bioanal Chem 2020; 412:6381-6389. [PMID: 32270246 DOI: 10.1007/s00216-020-02591-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 03/05/2020] [Accepted: 03/09/2020] [Indexed: 12/01/2022]
Abstract
Lercanidipine, a third-generation dihydropyridine calcium L-type channel blocker, redox behavior at different carbon electrode materials, in a wide pH range, using cyclic, square-wave, and differential pulse voltammetry, was studied. A comparison was made between unmodified glassy carbon electrode (GCE) and boron-doped diamond electrode (BDDE), and GCE and BDDE modified with a carbon black (CB) nanoparticle embedded within a dihexadecylphosphate (DHP) nanostructured film (CB-DHP/GCE and CB-DHP/BDDE). Lercanidipine oxidation, for 3.4 < pH < 9.5, is an irreversible, diffusion-controlled, pH-dependent process that occurs in two consecutive steps, with the transfer of one electron and one proton, at the N1 and C4 positions in the 1,4-dihydropyridine ring. For pH > 9.5, both oxidation processes are pH-independent and a pKa = 9.40 was determined. Lercanidipine reduction at pH = 7.0 is an irreversible process, and the lercanidipine reduction products are electroactive and follow a reversible electron transfer reaction. Lercanidipine electroanalytical determination, at a nanostructured GCE modified with a CB-DHP film (CB-DHP/GCE), with no need for N2 purging, with a detection limit of 0.058 μM (3.58 × 10-5 g L-1) and a quantification limit of 0.176 μM (1.08 × 10-4 g L-1), was achieved. Graphical abstract.
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Affiliation(s)
- Isabel Garrido Fernandes
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535, Coimbra, Portugal
| | - Ana-Maria Chiorcea-Paquim
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535, Coimbra, Portugal
| | - Ana Maria Oliveira-Brett
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535, Coimbra, Portugal.
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Chiorcea-Paquim AM, Enache TA, Oliveira-Brett AM. Electrochemistry of Alzheimer Disease Amyloid Beta Peptides. Curr Med Chem 2018; 25:4066-4083. [PMID: 29446720 DOI: 10.2174/0929867325666180214112536] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/18/2017] [Accepted: 05/18/2017] [Indexed: 11/22/2022]
Abstract
Alzheimer's disease (AD) is a widespread form of dementia that is estimated to affect 44.4 million people worldwide. AD pathology is closely related to the accumulation of amyloid beta (Aβ) peptides in fibrils and plagues, the small oligomeric intermediate species formed during the Aβ peptides aggregation presenting the highest neurotoxicity. This review discusses the recent advances on the Aβ peptides electrochemical characterization. The Aβ peptides oxidation at a glassy carbon electrode occurs in one or two steps, depending on the amino acid sequence, length and content. The first electron transfer reaction corresponds to the tyrosine Tyr10 amino acid residue oxidation, and the second to all three histidine (His6, His13 and His14) and one methionine (Met35) amino acid residues. The Aβ peptides aggregation and amyloid fibril formation are electrochemically detected via the electroactive amino acids oxidation peak currents decrease that occurs in a time dependent manner. The Aβ peptides redox behaviour is correlated with changes in the adsorption morphology from initially random coiled structures, corresponding to the Aβ peptide monomers in random coil or in α-helix conformations, to aggregates, protofibrils and two types of fibrils, corresponding to the Aβ peptides in a β-sheet configuration, observed by atomic force microscopy. Electrochemical studies of Aβ peptides aggregation, mediated by the interaction with metal ions, particularly zinc, copper and iron, and different methodologies concerning the detection of Aβ peptide biomarkers of AD in biological fluids, using electrochemical biosensors, are also discussed.
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Affiliation(s)
- Ana-Maria Chiorcea-Paquim
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535, Coimbra, Portugal
| | - Teodor Adrian Enache
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535, Coimbra, Portugal
| | - Ana Maria Oliveira-Brett
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra, 3004-535, Coimbra, Portugal
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Enache TA, Chiorcea-Paquim AM, Oliveira-Brett AM. Amyloid Beta Peptide VHHQ, KLVFF, and IIGLMVGGVV Domains Involved in Fibrilization: AFM and Electrochemical Characterization. Anal Chem 2018; 90:2285-2292. [PMID: 29314823 DOI: 10.1021/acs.analchem.7b04686] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The time-dependent structural modifications and oxidation behavior of specifically chosen five short amyloid beta (Aβ) peptides, Aβ1-16, Aβ1-28, Aβ10-20, Aβ12-28, and Aβ17-42, fragments of the complete human Aβ1-40 peptide, were investigated by atomic force microscopy (AFM) and voltammetry. The objective was to determine the influence of different Aβ domains (VHHQ that contains electroactive histidine H residues, KLVFF that is the peptide hydrophobic aggregation core, and IIGLMVGGVV that is the C-terminus hydrophobic region), and of Aβ peptide hydrophobicity, in the fibrilization mechanism. The short Aβ peptides absence of aggregation or the time-dependent aggregation mechanisms, at room temperature, in free chloride media, within the time window from 0 to 48 h, were established by AFM via changes in their adsorption morphology, and by differential pulse voltammetry, via modifications of the amino acid residues oxidation peak currents. The first oxidation peak was of tyrosine Y residue and the second peak was of histidine H and methionine M residues oxidation. A correlation between the presence of an intact highly hydrophobic KLVFF aggregation core and the time-dependent changes on the Aβ peptides aggregation was found. The hydrophobic C-terminal domain IIGLMVGGVV, present in the Aβ1-40 peptide, also contributed to accelerate the formation of Aβ1-40 peptide aggregates and fibrils.
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Affiliation(s)
- Teodor Adrian Enache
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra , 3004-535, Coimbra, Portugal
| | - Ana-Maria Chiorcea-Paquim
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra , 3004-535, Coimbra, Portugal
| | - Ana Maria Oliveira-Brett
- Department of Chemistry, Faculty of Sciences and Technology, University of Coimbra , 3004-535, Coimbra, Portugal
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Chiorcea-Paquim AM, Oliveira SCB, Diculescu VC, Oliveira-Brett AM. Applications of DNA-Electrochemical Biosensors in Cancer Research. Past, Present and Future Challenges of Biosensors and Bioanalytical Tools in Analytical Chemistry: A Tribute to Professor Marco Mascini 2017. [DOI: 10.1016/bs.coac.2017.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
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Chiorcea-Paquim AM, Rodrigues Pontinha AD, Oliveira-Brett AM. Quadruplex-targeting anticancer drug BRACO-19 voltammetric and AFM characterization. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.05.146] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Chiorcea-Paquim AM, Pontinha ADR, Eritja R, Lucarelli G, Sparapani S, Neidle S, Oliveira-Brett AM. Atomic Force Microscopy and Voltammetric Investigation of Quadruplex Formation between a Triazole-Acridine Conjugate and Guanine-Containing Repeat DNA Sequences. Anal Chem 2015; 87:6141-9. [DOI: 10.1021/acs.analchem.5b00743] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
| | | | - Ramon Eritja
- Institute for Research in Biomedicine, IQAC−CSIC, CIBER-BBN
Networking Centre on Bioengineering, Biomaterials and Nanomedicine, Barcelona, Spain
| | - Genny Lucarelli
- UCL
School of Pharmacy, University College London, London WC1N 1AX, U.K
| | - Silvia Sparapani
- UCL
School of Pharmacy, University College London, London WC1N 1AX, U.K
| | - Stephen Neidle
- UCL
School of Pharmacy, University College London, London WC1N 1AX, U.K
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Chiorcea-Paquim AM, Diculescu VC, Cervini P, Cavalheiro ETG, Oliveira Brett AM. Graphite–castor oil polyurethane composite electrode surfaces – AFM morphological and electrochemical characterisation. J Electroanal Chem (Lausanne) 2014. [DOI: 10.1016/j.jelechem.2014.07.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Rodrigues Pontinha AD, Chiorcea-Paquim AM, Eritja R, Oliveira-Brett AM. Quadruplex nanostructures of d(TGGGGT): influence of sodium and potassium ions. Anal Chem 2014; 86:5851-7. [PMID: 24794539 DOI: 10.1021/ac500624z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The Tetrahymena telomeric repeat sequence d(TG4T) contains only guanine (G) and thymine (T) bases and has medical and nanotechnological applications because of its ability to self-assemble into stiff tetra-molecular parallel-stranded G-quadruplexes. The hexadeoxynucleotide d(TG4T) was studied using atomic force microscopy (AFM) on the highly oriented pyrolytic graphite surface and differential pulse (DP) voltammetry at a glassy carbon electrode. The d(TG4T) single-strands self-assembled into G-quadruplex structures, very fast in K(+) ions solution and slowly in Na(+) ions containing solution. The G-quadruplex structures were detected in AFM by the adsorption of small spherical aggregates and by DP voltammetry by the G oxidation peak decrease and G-quartets oxidation peak occurrence, in a time and K(+) ions concentration dependent manner. In the presence of Na(+) ions, the d(TG4T) single-strands also slowly self-assembled into higher-order nanostructures, detected by AFM as short nanowires and nanostructured films that were never observed in K(+) ions containing solution.
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Chiorcea-Paquim AM, Santos PV, Oliveira-Brett AM. Atomic force microscopy and voltammetric characterisation of synthetic homo-oligodeoxynucleotides. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.03.103] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Chiorcea-Paquim AM, Santos PV, Eritja R, Oliveira-Brett AM. Self-assembled G-quadruplex nanostructures: AFM and voltammetric characterization. Phys Chem Chem Phys 2013; 15:9117-24. [PMID: 23644414 DOI: 10.1039/c3cp50866h] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
G-rich oligodeoxynucleotides (ODNs) have great medical and nanotechnological potential, because they can self-assemble into G-quadruplexes and higher-order nanostructures. The folding properties of d(G)10, d(TG9) and d(TG8T) ODNs were studied using atomic force microscopy (AFM) and voltammetry at carbon electrodes. Single-stranded ODNs, in Na(+) containing solutions and for short incubation times, were detected using AFM as network films and polymeric structures and using voltammetry by the occurrence of only the guanine oxidation peak. G-quadruplexes, in Na(+) containing solutions and long incubation times, or in K(+) containing solutions, were detected using AFM as spherical aggregates and using voltammetry by the decrease of the guanine oxidation peak and the occurrence of the G-quartet oxidation peak. Concerning the self-assembling into higher-order nanostructures, d(G)10 was the only sequence forming G-nanowires observed using AFM, d(TG9) formed short G-based super-structures that adsorbed as rod-like shape aggregates, and d(TG8T) formed no nanostructures, due to the presence of thymine residues at both 5' and 3' ends.
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Affiliation(s)
- Ana-Maria Chiorcea-Paquim
- Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, Coimbra, Portugal
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Diculescu VC, Chiorcea-Paquim AM, Eritja R, Oliveira-Brett AM. Evaluation of the structure–activity relationship of thrombin with thrombin binding aptamers by voltammetry and atomic force microscopy. J Electroanal Chem (Lausanne) 2011. [DOI: 10.1016/j.jelechem.2010.11.037] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Diculescu VC, Chiorcea-Paquim AM, Eritja R, Oliveira-Brett AM. Thrombin-Binding Aptamer Quadruplex Formation: AFM and Voltammetric Characterization. J Nucleic Acids 2010; 2010. [PMID: 20798847 PMCID: PMC2925381 DOI: 10.4061/2010/841932] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Accepted: 03/29/2010] [Indexed: 11/20/2022] Open
Abstract
The adsorption and the redox behaviour of thrombin-binding aptamer (TBA) and extended TBA (eTBA) were studied using atomic force microscopy and voltammetry at highly oriented pyrolytic graphite and glassy carbon. The different adsorption patterns and degree of surface coverage were correlated with the sequence base composition, presence/absence of K(+), and voltammetric behaviour of TBA and eTBA. In the presence of K(+), only a few single-stranded sequences present adsorption, while the majority of the molecules forms stable and rigid quadruplexes with no adsorption. Both TBA and eTBA are oxidized and the only anodic peak corresponds to guanine oxidation. Upon addition of K(+) ions, TBA and eTBA fold into a quadruplex, causing the decrease of guanine oxidation peak and occurrence of a new peak at a higher potential due to the oxidation of G-quartets. The higher oxidation potential of G-quartets is due to the greater difficulty of electron transfer from the inside of the quadruplex to the electrode surface than electron transfer from the more flexible single strands.
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Affiliation(s)
- Victor Constantin Diculescu
- Departamento de Quimica, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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Enache TA, Chiorcea-Paquim AM, Fatibello-Filho O, Oliveira-Brett AM. Hydroxyl radicals electrochemically generated in situ on a boron-doped diamond electrode. Electrochem commun 2009. [DOI: 10.1016/j.elecom.2009.04.017] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Diculescu VC, Chiorcea-Paquim AM, Tugulea L, Vivan M, Oliveira-Brett AM. Interaction of imatinib with liposomes: Voltammetric and AFM characterization. Bioelectrochemistry 2009; 74:278-88. [DOI: 10.1016/j.bioelechem.2008.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Revised: 10/15/2008] [Accepted: 10/15/2008] [Indexed: 12/18/2022]
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Corduneanu O, Diculescu VC, Chiorcea-Paquim AM, Oliveira-Brett AM. Shape-controlled palladium nanowires and nanoparticles electrodeposited on carbon electrodes. J Electroanal Chem (Lausanne) 2008. [DOI: 10.1016/j.jelechem.2008.07.034] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Martinovic J, Chiorcea-Paquim AM, Diculescu VC, Van Wyk J, Iwuoha E, Baker P, Mapolie S, Oliveira-Brett AM. Metallo-functionalized first-generation salicylaldimine poly(propylenimine) tetraamine dendrimers: Electrochemical study and atomic force microscopy imaging. Electrochim Acta 2008. [DOI: 10.1016/j.electacta.2008.02.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Diculescu VC, Chiorcea-Paquim AM, Corduneanu O, Oliveira-Brett AM. Palladium nanoparticles and nanowires deposited electrochemically: AFM and electrochemical characterization. J Solid State Electrochem 2007. [DOI: 10.1007/s10008-007-0275-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Chiorcea-Paquim AM, Piedade JAP, Wombacher R, Jäschke A, Oliveira-Brett AM. Atomic force microscopy and anodic voltammetry characterization of a 49-mer diels-alderase ribozyme. Anal Chem 2007; 78:8256-64. [PMID: 17165814 DOI: 10.1021/ac061040+] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Atomic force microscopy and differential pulse voltammetry were used to characterize the interaction of small highly structured ribozymes with two carbon electrode surfaces. The ribozymes spontaneously self-assemble in two-dimensional networks that cover the entire HOPG surface uniformly. The full-length ribozyme was adsorbed to a lesser extent than a truncated RNA sequence, presumably due to the formation of a more compact overall structure. All four nucleobases composing the ribozyme could be detected by anodic voltammetry on glassy carbon electrodes, and no signals corresponding to free nucleobases were found, indicating the integrity of the ribozyme molecules. Mg2+ cations significantly reduced the adsorption of ribozymes to the surfaces, in agreement with the stabilization of this ribozyme's compact, stable, and tightly folded tertiary structure by Mg2+ ions that could prevent the hydrophobic bases from interacting with the HOPG surface. Treatment with Pb2+ ions, on the other hand, resulted in an increased adsorption of the RNA due to well-known hydrolytic cleavage. The observed dependence of anodic peak currents on different folding states of RNA may provide an attractive method to electrochemically monitor structural changes associated with RNA folding, binding, and catalysis.
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Affiliation(s)
- A M Chiorcea-Paquim
- Departamento de Química, Faculdade de Ciências e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra, Portugal
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