1
|
Chen J, Gao H, Li Z, Li Y, Yuan Q. Ferriporphyrin-inspired MOFs as an artificial metalloenzyme for highly sensitive detection of H2O2 and glucose. CHINESE CHEM LETT 2020. [DOI: 10.1016/j.cclet.2020.03.052] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
|
2
|
Abstract
: Nanomaterial biosensors have revolutionized the entire scientific, technology, biomedical, materials science, and engineering fields. Among all nanomaterials, magnetic nanoparticles, microparticles, and beads are unique in offering facile conjugation of biorecognition probes for selective capturing of any desired analytes from complex real sample matrices (e.g., biofluids such as whole blood, serum, urine and saliva, tissues, food, and environmental samples). In addition, rapid separation of the particle-captured analytes by the simple use of a magnet for subsequent detection on a sensor unit makes the magnetic particle sensor approach very attractive. The easy magnetic isolation feature of target analytes is not possible with other inorganic particles, both metallic (e.g., gold) and non-metallic (e.g., silica), which require difficult centrifugation and separation steps. Magnetic particle biosensors have thus enabled ultra-low detection with ultra-high sensitivity that has traditionally been achieved only by radioactive assays and other tedious optical sources. Moreover, when traditional approaches failed to selectively detect low-concentration analytes in complex matrices (e.g., colorimetric, electrochemistry, and optical methods), magnetic particle-incorporated sensing strategies enabled sample concentration into a defined microvolume of large surface area particles for a straightforward detection. The objective of this article is to highlight the ever-growing applications of magnetic materials for the detection of analytes present in various real sample matrices. The central idea of this paper was to show the versatility and advantages of using magnetic particles for a variety of sample matrices and analyte types and the adaptability of different transducers with the magnetic particle approaches.
Collapse
|
3
|
Ranieri A, Bortolotti CA, Di Rocco G, Battistuzzi G, Sola M, Borsari M. Electrocatalytic Properties of Immobilized Heme Proteins: Basic Principles and Applications. ChemElectroChem 2019. [DOI: 10.1002/celc.201901178] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Antonio Ranieri
- Department of Life SciencesUniversity of Modena and Reggio Emilia Via Campi 103 41125 Modena Italy
| | - Carlo Augusto Bortolotti
- Department of Life SciencesUniversity of Modena and Reggio Emilia Via Campi 103 41125 Modena Italy
| | - Giulia Di Rocco
- Department of Life SciencesUniversity of Modena and Reggio Emilia Via Campi 103 41125 Modena Italy
| | - Gianantonio Battistuzzi
- Department of Chemical and Geological SciencesUniversity of Modena and Reggio Emilia Via Campi 103 41125 Modena Italy
| | - Marco Sola
- Department of Life SciencesUniversity of Modena and Reggio Emilia Via Campi 103 41125 Modena Italy
| | - Marco Borsari
- Department of Chemical and Geological SciencesUniversity of Modena and Reggio Emilia Via Campi 103 41125 Modena Italy
| |
Collapse
|
4
|
Yang Y, Wang S, Zhou Z, Zhang R, Shen H, Song J, Su P, Yang Y. Enhanced reusability and activity: DNA directed immobilization of enzyme on polydopamine modified magnetic nanoparticles. Biochem Eng J 2018. [DOI: 10.1016/j.bej.2018.05.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
|
5
|
Nerimetla R, Premaratne G, Liu H, Krishnan S. Improved electrocatalytic metabolite production and drug biosensing by human liver microsomes immobilized on amine-functionalized magnetic nanoparticles. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2018.05.085] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
|
6
|
Đurović M, Oszajca M, Stochel G, van Eldik R. The Influence of Redox‐Active Transition Metal Containing Micro‐ and Nanoparticles on the Properties of Representative Bioinorganic Reaction Systems. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201701421] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Mirjana Đurović
- Faculty of Chemistry Jagiellonian University Gronostajowa 2 30‐387 Kraków Poland
| | - Maria Oszajca
- Faculty of Chemistry Jagiellonian University Gronostajowa 2 30‐387 Kraków Poland
| | - Grażyna Stochel
- Faculty of Chemistry Jagiellonian University Gronostajowa 2 30‐387 Kraków Poland
| | - Rudi van Eldik
- Faculty of Chemistry Jagiellonian University Gronostajowa 2 30‐387 Kraków Poland
- Department of Chemistry and Pharmacy University of Erlangen‐Nuremberg Egerlandstr. 1 91058 Erlangen Germany
| |
Collapse
|
7
|
Premaratne G, Farias S, Krishnan S. Pyrenyl carbon nanostructures for ultrasensitive measurements of formaldehyde in urine. Anal Chim Acta 2017; 970:23-29. [PMID: 28433055 PMCID: PMC5443713 DOI: 10.1016/j.aca.2017.03.032] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 03/15/2017] [Accepted: 03/16/2017] [Indexed: 01/06/2023]
Abstract
Measurement of ultra-low (e.g., parts-per-billion) levels of small-molecule markers in body fluids (e.g., serum, urine, saliva) involves a considerable challenge in view of designing assay strategies with sensitivity and selectivity. Herein we report for the first time an amperometric nano-bioelectrode design that uniquely combines 1-pyrenebutyric acid units pi-pi stacked with carboxylated multiwalled carbon nanotubes on the surface of gold screen printed electrodes for covalent attachment of NAD+ dependent formaldehyde dehydrogenase (FDH). The designed enzyme bioelectrode offered 6 ppb formaldehyde detection in 10-times diluted urine with a wide dynamic range of 10 ppb to 10 ppm. Fourier transform infrared, Raman, and electrochemical impedance spectroscopic characterizations confirmed the successful design of the FDH bioelectrode. Flow injection analysis provided lower detection limit and greater affinity for formaldehyde (apparent KM 9.6 ± 1.2 ppm) when compared with stirred solution method (apparent KM 19.9 ± 4.6 ppm). Selectivity assays revealed that the bioelectrode was selective toward formaldehyde with a moderate cross-reactivity for acetaldehyde (∼25%) and negligible cross-reactivity toward propanaldehyde, acetone, methanol, and ethanol. Formaldehyde is an indoor pollutant, and studies have indicated neurotoxic characteristics and systemic toxic effects of this compound upon chronic and high doses of exposure. Moreover, reported chromatography and mass spectrometry methods identified elevated urine formaldehyde levels in patients with bladder cancer, dementia, and early stages of cognitive impairments compared to healthy people. Results demonstrate that pyrenyl carbon nanostructures-based FDH bioelectrode design represents novelty and simplicity for enzyme-selective electrochemical quantitation of small 30 Da formaldehyde. Broader applicability of the presented approach for other small-molecule markers is feasible that requires only the design of appropriate marker-specific enzyme systems or receptor molecules.
Collapse
Affiliation(s)
- Gayan Premaratne
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences Building, Stillwater, OK 74078, USA
| | - Sabrina Farias
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences Building, Stillwater, OK 74078, USA
| | - Sadagopan Krishnan
- Department of Chemistry, Oklahoma State University, 107 Physical Sciences Building, Stillwater, OK 74078, USA.
| |
Collapse
|
8
|
|
9
|
Hao N, Jiang L, Qian J, Wang K. Ultrasensitive electrochemical Ochratoxin A aptasensor based on CdTe quantum dots functionalized graphene/Au nanocomposites and magnetic separation. J Electroanal Chem (Lausanne) 2016. [DOI: 10.1016/j.jelechem.2016.09.053] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
|
10
|
Kong J, Yu X, Hu W, Hu Q, Shui S, Li L, Han X, Xie H, Zhang X, Wang T. A biomimetic enzyme modified electrode for H2O2 highly sensitive detection. Analyst 2016; 140:7792-8. [PMID: 26462299 DOI: 10.1039/c5an01335f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
An efficient catalyst based on artificial bionic peroxidase was synthesized for electrocatalysis. A poly(ethyleneimine)/Au nanoparticle composite (PEI-AuNP) was prepared and it was then linked to hemin via a coupling reaction between carboxyl groups in hemin and amino groups in PEI without the activation of a carboxyl group by carbodiimide. Fourier transform infrared (FTIR) spectroscopy verified the formation of amido bonds within the structure. The presence of AuNPs contributed greatly in establishing the amido bonds within the composite. Transmission electron microscopy (TEM) and UV-visible spectroscopy were also used to characterize the PEI-AuNP-hemin catalyst. PEI-AuNP-hemin exhibited intrinsic peroxidase-like catalytic activities. The PEI-AuNP-hemin deposited on a glass carbon electrode had strong sensing for H2O2 with a well-defined linear relationship between the amperometric response and H2O2 concentration in the range from 1 μM to 0.25 mM. The detection limit was 0.247 nM with a high sensitivity of 0.347 mA mM(-1) cm(-2). The peroxidase-like catalytic activity of PEI-AuNP-hemin is discussed in relation to its microstructure. The study suggests that PEI-AuNP-hemin may have promising application prospects in biocatalysis and bioelectronics.
Collapse
Affiliation(s)
- Jinming Kong
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, P. R. China.
| | - Xuehua Yu
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, P. R. China.
| | - Weiwen Hu
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, P. R. China.
| | - Qiong Hu
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, P. R. China.
| | - Sailan Shui
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, P. R. China.
| | - Lianzhi Li
- Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, P. R. China
| | - Xiaojun Han
- State Key Laboratory of Urban Water Resource and Environment, School of Chemical Engineering and Technology, Harbin Institute of Technology, Harbin 150001, P. R. China
| | - Huifang Xie
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, P. R. China.
| | - Xueji Zhang
- School of Environmental and Biological Engineering, Nanjing University of Science & Technology, Nanjing 210094, P. R. China. and Chemistry Department, College of Arts and Sciences, University of South Florida, East Fowler Ave, Tampa, Florida 33620-4202, USA
| | - Tianhe Wang
- Chemicobiology and Functional Materials Institute, School of Chemical Engineering, Nanjing University of Science & Technology, Nanjing 210094, P. R. China
| |
Collapse
|
11
|
Premaratne G, Nerimetla R, Matlock R, Sunday L, Hikkaduwa Koralege RS, Ramsey JD, Krishnan S. Stability, Scalability, and Reusability of a Volume Efficient Biocatalytic System Constructed on Magnetic Nanoparticles. Catal Sci Technol 2016; 6:2361-2369. [PMID: 27047654 PMCID: PMC4817543 DOI: 10.1039/c5cy01458a] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
This report investigates for the first time stability, scalability, and reusability characteristics of a protein nano-bioreactor useful for green synthesis of fine chemicals in aqueous medium extracting maximum enzyme efficiency. Enzyme catalysts conjugated with magnetic nanomaterials allow easy product isolation after a reaction involving simple application of a magnetic field. In this study, we examined a biocatalytic system made of peroxidase-like myoglobin (Mb), as a model protein, to covalently conjugate with poly(acrylic acid) functionalized magnetic nanoparticles (MNPs, 100 nm hydrodynamic diameter) to examine the catalytic stability, scalability, and reusability features of this bioconjugate. Application of the conjugate was effective for electrochemical reduction of organic and inorganic peroxides, and for both peroxide-mediated and electrocatalytic oxidation of the protein substrate 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) with greater turnover rates and product yields than Mb prepared in solution or MNP alone. Mb-attached MNPs displayed extensive catalytic stability even after 4 months of storage compared to Mb present in solution. Five- and ten-fold scale up of MNPs in the bioconjugates resulted in two- and four-fold increases in protein-catalyzed oxidation products, respectively. Nearly 40% of the initial product was present even after four reuses, which is advantageous for synthesizing sufficient products with a minimal investment of precious enzymes. Thus, the results obtained in this study are highly significant in guiding cost-effective development and efficient multiple uses of enzyme catalysts for biocatalytic, electrocatalytic, and biosensing applications via magnetic nanomaterials conjugation.
Collapse
Affiliation(s)
- Gayan Premaratne
- Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA
| | | | - Ryan Matlock
- Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA
| | - Loren Sunday
- Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA
| | | | - Joshua D. Ramsey
- School of Chemical Engineering, Oklahoma State University, Stillwater, OK 74078, USA
| | - Sadagopan Krishnan
- Department of Chemistry, Oklahoma State University, Stillwater, OK 74078, USA
| |
Collapse
|
12
|
Blaik RA, Lan E, Huang Y, Dunn B. Gold-Coated M13 Bacteriophage as a Template for Glucose Oxidase Biofuel Cells with Direct Electron Transfer. ACS NANO 2016; 10:324-32. [PMID: 26593851 DOI: 10.1021/acsnano.5b04580] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Glucose oxidase-based biofuel cells are a promising source of alternative energy for small device applications, but still face the challenge of achieving robust electrical contact between the redox enzymes and the current collector. This paper reports on the design of an electrode consisting of glucose oxidase covalently attached to gold nanoparticles that are assembled onto a genetically engineered M13 bacteriophage using EDC-NHS chemistry. The engineered phage is modified at the pIII protein to attach onto a gold substrate and serves as a high-surface-area template. The resulting "nanomesh" architecture exhibits direct electron transfer (DET) and achieves a higher peak current per unit area of 1.2 mA/cm(2) compared to most other DET attachment schemes. The final enzyme surface coverage on the electrode was calculated to be approximately 4.74 × 10(-8) mol/cm(2), which is a significant improvement over most current glucose oxidase (GOx) DET attachment methods.
Collapse
Affiliation(s)
- Rita A Blaik
- Department of Materials Science and Engineering, HSSEAS School of Engineering & Applied Sciences, University of California Los Angeles , 410 Westwood Plaza, 3111 Engineering V, Los Angeles, California 90095-1595, United States
| | - Esther Lan
- Department of Materials Science and Engineering, HSSEAS School of Engineering & Applied Sciences, University of California Los Angeles , 410 Westwood Plaza, 3111 Engineering V, Los Angeles, California 90095-1595, United States
| | - Yu Huang
- Department of Materials Science and Engineering, HSSEAS School of Engineering & Applied Sciences, University of California Los Angeles , 410 Westwood Plaza, 3111 Engineering V, Los Angeles, California 90095-1595, United States
| | - Bruce Dunn
- Department of Materials Science and Engineering, HSSEAS School of Engineering & Applied Sciences, University of California Los Angeles , 410 Westwood Plaza, 3111 Engineering V, Los Angeles, California 90095-1595, United States
| |
Collapse
|
13
|
"Stable-on-the-Table" Biosensors: Hemoglobin-Poly (Acrylic Acid) Nanogel BioElectrodes with High Thermal Stability and Enhanced Electroactivity. SENSORS 2015; 15:23868-85. [PMID: 26393601 PMCID: PMC4610568 DOI: 10.3390/s150923868] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Revised: 09/10/2015] [Accepted: 09/11/2015] [Indexed: 01/10/2023]
Abstract
In our efforts toward producing environmentally responsible but highly stable bioelectrodes with high electroactivities, we report here a simple, inexpensive, autoclavable high sensitivity biosensor based on enzyme-polymer nanogels. Met-hemoglobin (Hb) is stabilized by wrapping it in high molecular weight poly(acrylic acid) (PAA, MW 450k), and the resulting nanogels abbreviated as Hb-PAA-450k, withstood exposure to high temperatures for extended periods under steam sterilization conditions (122 °C, 10 min, 17–20 psi) without loss of Hb structure or its peroxidase-like activities. The bioelectrodes prepared by coating Hb-PAA-450k nanogels on glassy carbon showed well-defined quasi-reversible redox peaks at −0.279 and −0.334 V in cyclic voltammetry (CV) and retained >95% electroactivity after storing for 14 days at room temperature. Similarly, the bioelectrode showed ~90% retention in electrochemical properties after autoclaving under steam sterilization conditions. The ultra stable bioelectrode was used to detect hydrogen peroxide and demonstrated an excellent detection limit of 0.5 μM, the best among the Hb-based electrochemical biosensors. This is the first electrochemical demonstration of steam-sterilizable, storable, modular bioelectrode that undergoes reversible-thermal denaturation and retains electroactivity for protein based electrochemical applications.
Collapse
|
14
|
Walgama C, Nerimetla R, Materer NF, Schildkraut D, Elman JF, Krishnan S. A Simple Construction of Electrochemical Liver Microsomal Bioreactor for Rapid Drug Metabolism and Inhibition Assays. Anal Chem 2015; 87:4712-8. [DOI: 10.1021/ac5044362] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Affiliation(s)
- Charuksha Walgama
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Rajasekhara Nerimetla
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Nicholas F. Materer
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| | - Deniz Schildkraut
- Filmetrics Application Lab—Rochester, 250 Packett’s Landing, Fairport, New York 14450, United States
| | - James F. Elman
- Filmetrics Application Lab—Rochester, 250 Packett’s Landing, Fairport, New York 14450, United States
| | - Sadagopan Krishnan
- Department
of Chemistry, Oklahoma State University, Stillwater, Oklahoma 74078, United States
| |
Collapse
|
15
|
Singh V, Krishnan S. Voltammetric immunosensor assembled on carbon-pyrenyl nanostructures for clinical diagnosis of type of diabetes. Anal Chem 2015; 87:2648-54. [PMID: 25675332 DOI: 10.1021/acs.analchem.5b00016] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Herein we report the first serum insulin voltammetric immunosensor for diagnosis of type 1 and type 2 diabetic disorders. The sensor is composed of multiwalled carbon nanotube-pyrenebutyric acid frameworks on edge plane pyrolytic graphite electrodes (PGE/MWNT/Py) to which an anti-insulin antibody was covalently attached. The detection of picomolar levels of serum insulin binding to the surface antibody was achieved by monitoring the decrease in voltammetric current signals of a redox probe taken in the electrolyte solution. This method offered a detection limit of 15 pM for free insulin present in serum. This detection limit was further lowered to 5 pM by designing serum insulin conjugates with poly(acrylic acid)-functionalized magnetite nanoparticles (100 nm hydrodynamic diameter) and detecting the binding of MNP-serum insulin conjugate to the surface insulin-antibody on PGE/MWNT/Py electrodes. When tested on real patient serum samples, the sensor accurately measured insulin levels. To our knowledge, this is the first report of a voltammetric immunosensor capable of both diagnosing and distinguishing the type of diabetes based on serum insulin levels in diabetic patients.
Collapse
Affiliation(s)
- Vini Singh
- Department of Chemistry, Oklahoma State University , Stillwater, Oklahoma 74078, United States
| | | |
Collapse
|
16
|
Prasad KS, Walgama C, Krishnan S. Enhanced electroactivity and substrate affinity of microperoxidase-11 attached to pyrene-linkers π–π stacked on carbon nanostructure electrodes. RSC Adv 2015. [DOI: 10.1039/c4ra14361b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
An exceptionally large electroactively connected microperoxidase-11 (MP-11) with strong affinity for organic peroxide and offering a high electrocatalytic reduction current density of 7.5 mA cm−2 is achieved for the first time.
Collapse
|
17
|
Nerimetla R, Walgama C, Ramanathan R, Krishnan S. Correlating the Electrochemical Kinetics of Myoglobin-Films to pH Dependent Meat Color. ELECTROANAL 2014. [DOI: 10.1002/elan.201300630] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
|
18
|
Direct Electrochemistry and Electrocatalysis of Horseradish Peroxidase Immobilized in a DNA/Chitosan-Fe₃O₄ Magnetic Nanoparticle Bio-Complex Film. MATERIALS 2014; 7:1069-1083. [PMID: 28788500 PMCID: PMC5453076 DOI: 10.3390/ma7021069] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 12/25/2013] [Accepted: 01/27/2014] [Indexed: 01/21/2023]
Abstract
A DNA/chitosan-Fe3O4 magnetic nanoparticle bio-complex film was constructed for the immobilization of horseradish peroxidase (HRP) on a glassy carbon electrode. HRP was simply mixed with DNA, chitosan and Fe3O4 nanoparticles, and then applied to the electrode surface to form an enzyme-incorporated polyion complex film. Scanning electron microscopy (SEM) was used to study the surface features of DNA/chitosan/Fe3O4/HRP layer. The results of electrochemical impedance spectroscopy (EIS) show that Fe3O4 and enzyme were successfully immobilized on the electrode surface by the DNA/chitosan bio-polyion complex membrane. Direct electron transfer (DET) and bioelectrocatalysis of HRP in the DNA/chitosan/Fe3O4 film were investigated by cyclic voltammetry (CV) and constant potential amperometry. The HRP-immobilized electrode was found to undergo DET and exhibited a fast electron transfer rate constant of 3.7 s−1. The CV results showed that the modified electrode gave rise to well-defined peaks in phosphate buffer, corresponding to the electrochemical redox reaction between HRP(Fe(III)) and HRP(Fe(II)). The obtained electrode also displayed an electrocatalytic reduction behavior towards H2O2. The resulting DNA/chitosan/Fe3O4/HRP/glassy carbon electrode (GCE) shows a high sensitivity (20.8 A·cm−2·M−1) toward H2O2. A linear response to H2O2 measurement was obtained over the range from 2 μM to 100 μM (R2 = 0.99) and an amperometric detection limit of 1 μM (S/N = 3). The apparent Michaelis-Menten constant of HRP immobilized on the electrode was 0.28 mM. Furthermore, the electrode exhibits both good operational stability and storage stability.
Collapse
|