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Lavanya V, Pavithra D, Mohanapriya A, Santhakumar K, Senthil Kumar A. A π-π Bonding-Assisted Molecular-Wiring of Folded-Cytochrome c and Naphthoquinone and Its Electron-Relay-Based Bioelectrocatalytic H 2O 2 Reduction Reaction Visualized by Redox-Competitive Scanning Electrochemical Microscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:11556-11570. [PMID: 37429831 DOI: 10.1021/acs.langmuir.3c00941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/12/2023]
Abstract
The electron-transfer (ET) reaction of cytochrome c (Cytc) protein with biomolecules is a cutting-edge research area of interest in understanding the functionalities of natural systems. Several electrochemical biomimicking studies based on Cytc-protein-modified electrodes prepared via electrostatic interaction and covalent bonding approaches have been reported. Indeed, natural enzymes involve multiple types of bonding, such as hydrogen, ionic, covalent, and π-π, etc. In this work, we explore a Cytc-protein chemically modified glassy carbon electrode (GCE/CB@NQ/Cytc) prepared via π-π bonding using graphitic carbon as an underlying surface and an aromatic organic molecule, naphthoquinone (NQ), as a cofactor for an effective ET reaction. A simple drop-casting technique-based preparation of GCE/CB@NQ showed a distinct surface-confined redox peak at a standard electrode potential (E°) = -0.2 V vs Ag/AgCl (surface excess = 21.3 nmol cm-2) in pH 7 phosphate buffer solution. A control experiment of modification of NQ on an unmodified GCE failed to show any such unique feature. For the preparation of GCE/CB@NQ/Cytc, a dilute solution of Cytc-pH 7 phosphate buffer was drop-cast on the GCE/CB@NQ surface, wherein the protein folding and denaturalization-based complication and its associated ET functionalities were avoided. Molecular dynamics simulation studies show the complexation of NQ with Cytc at the protein binding sites. The protein-bound surface shows an efficient and selective bioelectrocatalytic reduction performance of H2O2, as demonstrated using cyclic voltammetry and amperometric i-t techniques. Finally, the redox-competition scanning electrochemical microscopy (RC-SECM) technique was adopted for in situ visualization of the electroactive adsorbed surface. The RC-SECM images clearly show the regions of highly bioelectrocatalytic active sites of Cytc-proteins bound to NQ molecules on a graphitic carbon surface. The binding of Cytc with NQ has significant implications for studying the biological electron transport mechanism, and the proposed method provides the requisite framework for such a study.
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Affiliation(s)
- V Lavanya
- Nano and Bioelectrochemistry Research Laboratory, Carbon Dioxide and Green Technology Research Centre, Vellore Institute of Technology University, Vellore 632 014, Tamil Nadu, India
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology University, Vellore 632 014, Tamil Nadu, India
| | - Dhamodharan Pavithra
- Department of Biotechnology, School of Biosciences and Technology, Vellore Institute of Technology University, Vellore 632 014, Tamil Nadu, India
| | - Arumugam Mohanapriya
- Department of Biotechnology, School of Biosciences and Technology, Vellore Institute of Technology University, Vellore 632 014, Tamil Nadu, India
| | - K Santhakumar
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology University, Vellore 632 014, Tamil Nadu, India
| | - Annamalai Senthil Kumar
- Nano and Bioelectrochemistry Research Laboratory, Carbon Dioxide and Green Technology Research Centre, Vellore Institute of Technology University, Vellore 632 014, Tamil Nadu, India
- Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology University, Vellore 632 014, Tamil Nadu, India
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Mai BD. Anomalous phase transition, polarization switching and relaxation in a novel composite consisting of dimethylammonium aluminum sulphate hexahydrate and oxidized multiwalled carbon nanotubes. J MACROMOL SCI B 2023. [DOI: 10.1080/00222348.2023.2185021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Affiliation(s)
- Bich Dung Mai
- Institute of Biotechnology and Food Technology, Industrial University of Ho Chi Minh City, Ho Chi Minh City, Vietnam
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Monteiro T, Moreira M, Gaspar SBR, Almeida MG. Bilirubin oxidase as a single enzymatic oxygen scavenger for the development of reductase-based biosensors in the open air and its application on a nitrite biosensor. Biosens Bioelectron 2022; 217:114720. [PMID: 36148736 DOI: 10.1016/j.bios.2022.114720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 09/09/2022] [Accepted: 09/10/2022] [Indexed: 11/25/2022]
Abstract
The commercialization of amperometric or voltammetric biosensors that operate at potentials lower than -0.2 V vs SHE has been hindered by the need for anoxic working conditions due to the interference of molecular oxygen, whose electrochemical reduction can potentially mask other redox processes and generate reactive oxygen species (ROS). A deoxygenation step must be thus integrated into the analytical process. To this end, several (bio)chemical oxygen scavenging systems have been proposed, such as the bi-enzyme system, glucose oxidase/catalase. Still, a few issues persist owing to enzyme impurities and the formation of oxygen reactive species. Here in, we propose a new mono-enzymatic oxygen scavenging system composed of a multicopper oxidase as a single biocatalytic oxygen reducer. As a model, we used bilirubin oxidase (BOD), which catalyzes the direct reduction of oxygen to water in the presence of an electron donor substrate, without releasing hydrogen peroxide. Both the direct electron transfer and mediated electrochemical approach using different co-substrates were screened for the ability to promote the enzymatic reduction of oxygen. An optimal combination of BOD with sodium ascorbate proved to be quick (5 min) and effective. It was subsequently employed, as a proof-of-concept, in a voltammetric biosensor based on a multiheme cytochrome c nitrite reductase, which performs the reduction of nitrite to ammonia at potentials below -0.3 V vs SHE. The nitrite biosensor performed well under ambient air, with no need for a second enzyme to account for the build-up of oxygen reactive intermediaries.
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Affiliation(s)
- Tiago Monteiro
- UCIBIO - Applied Molecular Biosciences Unit, Department of Chemistry / Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
| | - Miguel Moreira
- UCIBIO - Applied Molecular Biosciences Unit, Department of Chemistry / Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
| | - Sara B R Gaspar
- UCIBIO - Applied Molecular Biosciences Unit, Department of Chemistry / Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal
| | - Maria Gabriela Almeida
- UCIBIO - Applied Molecular Biosciences Unit, Department of Chemistry / Department of Life Sciences, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2829-516, Caparica, Portugal; Centro de investigação interdisciplinar Egas Moniz (CiiEM), Instituto Universitário Egas Moniz, Campus Universitário, Quinta da Granja, 2829-511, Caparica, Portugal.
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Monteiro T, Coelho AR, Moreira M, Viana AS, Almeida MG. Interfacing the enzyme multiheme cytochrome c nitrite reductase with pencil lead electrodes: Towards a disposable biosensor for cyanide surveillance in the environment. Biosens Bioelectron 2021; 191:113438. [PMID: 34171736 DOI: 10.1016/j.bios.2021.113438] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 10/21/2022]
Abstract
The present study reports a novel voltammetric biosensor for cyanide based on its inhibitory effect on cytochrome c nitrite reductase (ccNiR). Interestingly, the earlier development of a point-of-care test for nitrite based on the direct electrochemistry of ccNiR has shown that the cyanide inhibition depends on the type of carbon material employed as transducer (Monteiro et al., 2019). In this work, commercial graphite pencil leads were employed in the construction of both working and pseudo-reference electrodes, with ccNiR being simply drop casted onto the former. In this way, we produced a functional and fully integrated voltammetric biosensor for nitrite quantification that also allows to observe a decrease in the catalytic current due to cyanide addition. Under turnover conditions, the biosensor showed a linear response with the logarithm of cyanide concentration in the 5-76 μM (cyclic voltammetry) and 1-40 μM (square-wave voltammetry) ranges, with a sensitivity of 20-25% ln [cyanide μM]-1 and a detection limit of 0.86-4.4 μM. The application of the pencil lead as a putative pseudo-reference was very promising, since the potentials profile matched those observed with a true reference electrode (Ag/AgCl). Overall, the direct electron transfer between ccNiR and a pencil lead electrode was demonstrated for the first time, with cyanide-induced inhibition being easily monitored, paving the way for the employment of these low-cost bioelectrodes as cyanide probes for on-site surveillance of aquatic environments.
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Affiliation(s)
- Tiago Monteiro
- UCIBIO, REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Monte de Caparica, 2829-516, Portugal
| | - Ana Rita Coelho
- Departamento Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisboa, Portugal
| | - Miguel Moreira
- UCIBIO, REQUIMTE, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Monte de Caparica, 2829-516, Portugal
| | - Ana S Viana
- Centro de Química Estrutural, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016, Lisboa, Portugal
| | - Maria Gabriela Almeida
- Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Instituto Universitário Egas Moniz, Campus Universitário, Quinta da Granja, Caparica, 2829-511, Portugal.
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Abstract
Heme proteins take part in a number of fundamental biological processes, including oxygen transport and storage, electron transfer, catalysis and signal transduction. The redox chemistry of the heme iron and the biochemical diversity of heme proteins have led to the development of a plethora of biotechnological applications. This work focuses on biosensing devices based on heme proteins, in which they are electronically coupled to an electrode and their activity is determined through the measurement of catalytic currents in the presence of substrate, i.e., the target analyte of the biosensor. After an overview of the main concepts of amperometric biosensors, we address transduction schemes, protein immobilization strategies, and the performance of devices that explore reactions of heme biocatalysts, including peroxidase, cytochrome P450, catalase, nitrite reductase, cytochrome c oxidase, cytochrome c and derived microperoxidases, hemoglobin, and myoglobin. We further discuss how structural information about immobilized heme proteins can lead to rational design of biosensing devices, ensuring insights into their efficiency and long-term stability.
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Elemike EE, Fayemi OE, Ekennia AC, Onwudiwe DC, Ebenso EE. Silver Nanoparticles Mediated by Costus afer Leaf Extract: Synthesis, Antibacterial, Antioxidant and Electrochemical Properties. Molecules 2017; 22:E701. [PMID: 28468278 PMCID: PMC6154536 DOI: 10.3390/molecules22050701] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Revised: 04/12/2017] [Accepted: 04/20/2017] [Indexed: 12/30/2022] Open
Abstract
Synthesis of metallic and semiconductor nanoparticles through physical and chemical routes has been extensively reported. However, green synthesized metal nanoparticles are currently in the limelight due to the simplicity, cost-effectiveness and eco-friendliness of their synthesis. This study explored the use of aqueous leaf extract of Costus afer in the synthesis of silver nanoparticles (CA-AgNPs). The optical and structural properties of the resulting silver nanoparticles were studied using UV-visible spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infra-red spectrophotometer (FTIR). TEM images of the silver nanoparticles confirmed the existence of monodispersed spherical nanoparticles with a mean size of 20 nm. The FTIR spectra affirmed the presence of phytochemicals from the Costus afer leaf extract on the surface of the silver nanoparticles. The electrochemical characterization of a CA-AgNPs/multiwalled carbon nanotubes (MWCNT)-modified electrode was carried out to confirm the charge transfer properties of the nanocomposites. The comparative study showed that the CA-AgNPs/MWCNT-modified electrode demonstrated faster charge transport behaviour. The anodic current density of the electrodes in Fe(CN)₆]4-/[Fe(CN)₆]3- redox probe follows the order: GCE/CA-Ag/MWCNT (550 mA/cm²) > GCE/MWCNT (270 mA/cm²) > GCE (80 mA/cm²) > GCE/CA-Ag (7.93 mA/cm²). The silver nanoparticles were evaluated for their antibacterial properties against Gram negative (Escherichia coli, Klebsiella pneumonia, Pseudomonas aeruginosa) and Gram positive (Bacillus subtilis and Staphylococcus aureus) pathogens. The nanoparticles exhibited better inhibition of the bacterial strains compared to the precursors (leaf extract of Costus afer and silver nitrate). Furthermore, the ability of the nanoparticles to scavenge DPPH radicals at different concentrations was studied using the DPPH radical scavenging assay and compared to that of the leaf extract and ascorbic acid. The nanoparticles were better DPPH scavengers compared to the leaf extract and their antioxidant properties compared favorably the antioxidant results of ascorbic acid. The green approach to nanoparticles synthesis carried out in this research work is simple, non-polluting, inexpensive and non-hazardous.
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Affiliation(s)
- Elias E Elemike
- Material Science Innovation and Modelling (MaSIM) Research Focus Area, Faculty of Agriculture, Science and Technology, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa.
- Department of Chemistry, School of Mathematics and Physical Sciences, Faculty of Agriculture, Science and Technology, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa.
- Department of Chemistry, College of Science, Federal University of Petroleum Resources, P.M.B 1221 Effurun, Delta State, Nigeria.
| | - Omolola E Fayemi
- Material Science Innovation and Modelling (MaSIM) Research Focus Area, Faculty of Agriculture, Science and Technology, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa.
- Department of Chemistry, School of Mathematics and Physical Sciences, Faculty of Agriculture, Science and Technology, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa.
| | - Anthony C Ekennia
- Department of Chemistry, Federal University Ndufu-Alike Ikwo (FUNAI), P.M.B 1010 Abakiliki, Ebonyi State, Nigeria.
| | - Damian C Onwudiwe
- Material Science Innovation and Modelling (MaSIM) Research Focus Area, Faculty of Agriculture, Science and Technology, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa.
- Department of Chemistry, School of Mathematics and Physical Sciences, Faculty of Agriculture, Science and Technology, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa.
| | - Eno E Ebenso
- Material Science Innovation and Modelling (MaSIM) Research Focus Area, Faculty of Agriculture, Science and Technology, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa.
- Department of Chemistry, School of Mathematics and Physical Sciences, Faculty of Agriculture, Science and Technology, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa.
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