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Pan J, Xu W, Li W, Chen S, Dai Y, Yu S, Zhou Q, Xia F. Electrochemical Aptamer-Based Sensors with Tunable Detection Range. Anal Chem 2023; 95:420-432. [PMID: 36625123 DOI: 10.1021/acs.analchem.2c04498] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Jing Pan
- State Key Laboratory of Biogeology and Environmental Geology, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Wenxia Xu
- State Key Laboratory of Biogeology and Environmental Geology, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Wanlu Li
- State Key Laboratory of Biogeology and Environmental Geology, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Shuwen Chen
- State Key Laboratory of Biogeology and Environmental Geology, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Yu Dai
- State Key Laboratory of Biogeology and Environmental Geology, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Shanwu Yu
- State Key Laboratory of Biogeology and Environmental Geology, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Qitao Zhou
- State Key Laboratory of Biogeology and Environmental Geology, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
| | - Fan Xia
- State Key Laboratory of Biogeology and Environmental Geology, Faculty of Materials Science and Chemistry, China University of Geosciences, Wuhan 430074, China
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2
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Mei Y, Yang S, Li C, Chen W, Liu R, Xu K. A signal-on fluorescent biosensor for mercury detection based on a cleavable phosphorothioate RNA fluorescent probe and metal-organic frameworks. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2022; 14:4418-4425. [PMID: 36300422 DOI: 10.1039/d2ay01476a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Mercury contamination is a major environmental concern. In this work, we used a cleavable phosphorothioate (PS) fluorescence probe quenched by UiO-66-NH2 to develop a "signal-on" fluorescent biosensor for Hg2+ detection. The probe was bound to UiO-66-NH2 through π-π stacking and hydrogen bonding, thereby extinguishing the fluorescence of the FAM-labelled probe. The PS site was cleaved in the presence of Hg2+, releasing the FAM group and significantly enhancing the fluorescence signal. The intensity of the fluorescence linearly rose as the Hg2+ concentration increased in the range of 1-100 nM (R2 = 0.994), and the limit of detection was 0.118 nM (S/N = 3). This biosensor demonstrated high selectivity for Hg2+ and was effectively applied to quantification of Hg2+ in various water samples with acceptable recovery rates. These results suggest that this practical, straightforward technology is a good option for monitoring mercury ions in the environment.
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Affiliation(s)
- Yang Mei
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, PR China.
- School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, PR China
| | - Si Yang
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, PR China.
- School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, PR China
| | - Chenxi Li
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, PR China.
| | - Wenliang Chen
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, PR China.
- School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, PR China
| | - Rong Liu
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, PR China.
| | - Kexin Xu
- State Key Laboratory of Precision Measuring Technology and Instruments, Tianjin University, Tianjin 300072, PR China.
- School of Precision Instruments and Optoelectronics Engineering, Tianjin University, Tianjin 300072, PR China
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Downs AM, Gerson J, Hossain MN, Ploense K, Pham M, Kraatz HB, Kippin T, Plaxco KW. Nanoporous Gold for the Miniaturization of In Vivo Electrochemical Aptamer-Based Sensors. ACS Sens 2021; 6:2299-2306. [PMID: 34038076 DOI: 10.1021/acssensors.1c00354] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Electrochemical aptamer-based sensors enable real-time molecular measurements in the living body. The spatial resolution of these measurements and ability to perform measurements in targeted locations, however, is limited by the length and width of the device's working electrode. Historically, achieving good signal to noise in the complex, noisy in vivo environment has required working electrode lengths of 3-6 mm. To enable sensor miniaturization, here we have enhanced the signaling current obtained for a sensor of given macroscopic dimensions by increasing its surface area. Specifically, we produced nanoporous gold via an electrochemical alloying/dealloying technique to increase the microscopic surface area of our working electrodes by up to 100-fold. Using this approach, we have miniaturized in vivo electrochemical aptamer-based (EAB) sensors (here using sensors against the antibiotic, vancomycin) by a factor of 6 while retaining sensor signal and response times. Conveniently, the fabrication of nanoporous gold is simple, parallelizable, and compatible with both two- and three-dimensional electrode architectures, suggesting that it may be of value to a range of electrochemical biosensor applications.
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Affiliation(s)
- Alex M. Downs
- Department of Mechanical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
- Center for Bioengineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Julian Gerson
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - M. Nur Hossain
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C1A4, Canada
| | - Kyle Ploense
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Michael Pham
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Heinz-Bernhard Kraatz
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Ontario M1C1A4, Canada
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Tod Kippin
- Department of Psychological and Brain Sciences, University of California Santa Barbara, Santa Barbara, California 93106, United States
- The Neuroscience Research Institute and Department of Molecular Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, California 93106, United States
| | - Kevin W. Plaxco
- Department of Mechanical Engineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
- Center for Bioengineering, University of California Santa Barbara, Santa Barbara, California 93106, United States
- Department of Chemistry and Biochemistry, University of California Santa Barbara, Santa Barbara, California 93106, United States
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Raja IS, Vedhanayagam M, Preeth DR, Kim C, Lee JH, Han DW. Development of Two-Dimensional Nanomaterials Based Electrochemical Biosensors on Enhancing the Analysis of Food Toxicants. Int J Mol Sci 2021; 22:3277. [PMID: 33806998 PMCID: PMC8005143 DOI: 10.3390/ijms22063277] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/19/2021] [Accepted: 03/21/2021] [Indexed: 12/25/2022] Open
Abstract
In recent times, food safety has become a topic of debate as the foodborne diseases triggered by chemical and biological contaminants affect human health and the food industry's profits. Though conventional analytical instrumentation-based food sensors are available, the consumers did not appreciate them because of the drawbacks of complexity, greater number of analysis steps, expensive enzymes, and lack of portability. Hence, designing easy-to-use tests for the rapid analysis of food contaminants has become essential in the food industry. Under this context, electrochemical biosensors have received attention among researchers as they bear the advantages of operational simplicity, portability, stability, easy miniaturization, and low cost. Two-dimensional (2D) nanomaterials have a larger surface area to volume compared to other dimensional nanomaterials. Hence, researchers nowadays are inclined to develop 2D nanomaterials-based electrochemical biosensors to significantly improve the sensor's sensitivity, selectivity, and reproducibility while measuring the food toxicants. In the present review, we compile the contribution of 2D nanomaterials in electrochemical biosensors to test the food toxicants and discuss the future directions in the field. Further, we describe the types of food toxicity, methodologies quantifying food analytes, how the electrochemical food sensor works, and the general biomedical properties of 2D nanomaterials.
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Affiliation(s)
| | | | - Desingh Raj Preeth
- Chemical Biology and Nanobiotechnology Laboratory, AU-KBC Research Centre, Anna University, MIT Campus, Chromepet, Chennai 600 044, India;
| | - Chuntae Kim
- BIO-IT Foundry Technology Institute, Pusan National University, Busan 46241, Korea; (I.S.R.); (C.K.)
| | - Jong Hun Lee
- Department of Food Science and Biotechnology, Gachon University, Seongnam 13120, Korea
| | - Dong Wook Han
- BIO-IT Foundry Technology Institute, Pusan National University, Busan 46241, Korea; (I.S.R.); (C.K.)
- Department of Cogno-Mechatronics Engineering, College of Nanoscience & Nanotechnology, Pusan National University, Busan 46241, Korea
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5
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Preparation, Modification, Characterization, and Biosensing Application of Nanoporous Gold Using Electrochemical Techniques. NANOMATERIALS 2018; 8:nano8030171. [PMID: 29547580 PMCID: PMC5869662 DOI: 10.3390/nano8030171] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 03/13/2018] [Accepted: 03/13/2018] [Indexed: 12/21/2022]
Abstract
Nanoporous gold (np-Au), because of its high surface area-to-volume ratio, excellent conductivity, chemical inertness, physical stability, biocompatibility, easily tunable pores, and plasmonic properties, has attracted much interested in the field of nanotechnology. It has promising applications in the fields of catalysis, bio/chemical sensing, drug delivery, biomolecules separation and purification, fuel cell development, surface-chemistry-driven actuation, and supercapacitor design. Many chemical and electrochemical procedures are known for the preparation of np-Au. Recently, researchers are focusing on easier and controlled ways to tune the pores and ligaments size of np-Au for its use in different applications. Electrochemical methods have good control over fine-tuning pore and ligament sizes. The np-Au electrodes that are prepared using electrochemical techniques are robust and are easier to handle for their use in electrochemical biosensing. Here, we review different electrochemical strategies for the preparation, post-modification, and characterization of np-Au along with the synergistic use of both electrochemistry and np-Au for applications in biosensing.
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7
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Mesbahi A, Famouri F, Ahar MJ, Ghaffari MO, Ghavami SM. A study on the imaging characteristics of Gold nanoparticles as a contrast agent in X-ray computed tomography. POLISH JOURNAL OF MEDICAL PHYSICS AND ENGINEERING 2017. [DOI: 10.1515/pjmpe-2017-0003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Abstract
Aim: In the current study, some imaging characteristics of AuNPs were quantitatively analyzed and compared with two conventional contrast media (CM) including Iodine and Gadolinium by using of a cylindrical phantom.
Methods: AuNPs were synthesized with the mean diameter of 16 nm and were equalized to the concentration of 0.5, 1, 2 and 4 mg/mL in the same volumes. A cylindrical phantom resembling the head and neck was fabricated and drilled to contain small tubes filled with Iodine, Gadolinium, and AuNPs as contrast media. The phantom was scanned in different exposure techniques and CT numbers of three studied contrast media inside test tubes were measured in terms of Hounsfield Unit (HU). The imaging parameters of the noise and contrast to noise ratios (CNR) were calculated for all studied CMs.
Results: AuNPs showed 128% and 166% higher CT number in comparison with Iodine and Gadolinium respectively. Also, Iodine had a greater CT number than Gadolinium for the same exposure techniques and concentration. The maximum CT number for AuNPs and studied contrast materials was obtained at the highest mAs and the lowest tube potential. The maximum CT number were 1033±11 (HU) for AuNP, 565±10 (HU) for Iodine, 458±11 for Gadolinium. Moreover, the maximum CNRs of 433±117, 203±53, 145±37 were found for AuNPs, Iodine and Gadolinium respectively.
Conclusion: The contrast agent based on AuNPs showed higher imaging quality in terms of contrast and noise relative to other iodine and gadolinium based contrast media in X-ray computed tomography. Application of the AuNPs as a contrast medium in x-ray CT is recommended.
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Affiliation(s)
- Asghar Mesbahi
- Medical Physics Department, Medical School, Tabriz University of Medical Sciences, Tabriz, Iran (Islamic Republic of)
- Medical Radiation Sciences Research Team, Tabriz University of Medical Sciences, Tabriz, Iran (Islamic Republic of)
| | - Fatemeh Famouri
- Medical Physics Department, Medical School, Tabriz University of Medical Sciences, Tabriz, Iran (Islamic Republic of)
| | - Mohammad Johari Ahar
- Department of Medicinal Chemistry, School of Pharmacy, Ardabil University of Medical Sciences, Iran (Islamic Republic of)
| | - Maryam Olade Ghaffari
- Department of Radiology, Shohada Hospital, Tabriz University of Medical Sciences, Tabriz, Iran (Islamic Republic of)
| | - Seyed Mostafa Ghavami
- Department of Radiology, Shohada Hospital, Tabriz University of Medical Sciences, Tabriz, Iran (Islamic Republic of)
- Radiology Department, Paramedical School, Tabriz University of Medical Sciences, Tabriz, Iran (Islamic Republic of)
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8
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Patterned gold electrode prepared from optical discs display largely enhanced electrochemical sensitivity as exemplified in a sensor for hydrogen peroxide. Mikrochim Acta 2016. [DOI: 10.1007/s00604-016-2008-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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9
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Tello A, Cao R, Marchant MJ, Gomez H. Conformational Changes of Enzymes and Aptamers Immobilized on Electrodes. Bioconjug Chem 2016; 27:2581-2591. [PMID: 27748603 DOI: 10.1021/acs.bioconjchem.6b00553] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Conformation constitutes a vital property of biomolecules, especially in the cases of enzymes and aptamers, and is essential in defining their molecular recognition ability. When biomolecules are immobilized on electrode surfaces, it is very important to have a control on all the possible conformational changes that may occur, either upon the recognition of their targets or by undesired alterations. Both enzymes and aptamers immobilized on electrodes are susceptible to conformational changes as a response to the nature of the charge of the surface and of the surrounding environment (pH, temperature, ionic strength, etc.). The main goal of this review is to analyze how the conformational changes of enzymes and aptamers immobilized on electrode surfaces have been treated in reports on biosensors and biofuel cells. This topic was selected due to insufficient information found on the actual conformational changes involved in the function of these bioelectrochemical devices despite its importance.
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Affiliation(s)
- Alejandra Tello
- Universidad Andres Bello , Bionanotechnology and Microbiology Lab, Center for Bioinformatics and Integrative Biology (CBIB), Facultad de Ciencias Biológicas, República 239, Santiago, Chile
| | - Roberto Cao
- Instituto de Química, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso , Avenida Universidad 330, Curauma, Valparaíso, Chile
| | - María José Marchant
- Instituto de Química, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso , Avenida Universidad 330, Curauma, Valparaíso, Chile
| | - Humberto Gomez
- Instituto de Química, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso , Avenida Universidad 330, Curauma, Valparaíso, Chile
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Li Y, Wang Q, Zhang Y, Deng D, He H, Luo L, Wang Z. A label-free electrochemical aptasensor based on graphene oxide/double-stranded DNA nanocomposite. Colloids Surf B Biointerfaces 2016; 145:160-166. [PMID: 27182650 DOI: 10.1016/j.colsurfb.2016.04.048] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 04/07/2016] [Accepted: 04/29/2016] [Indexed: 10/21/2022]
Abstract
A novel label-free electrochemical impedance aptasensor based on a gold nanoparticles/double-stranded DNA-graphene (AuNPs/dsDNA-GO) nanocomposite modified glassy carbon electrode was presented for quantitative determination of thrombin. GO was covalently functionalized with dsDNA via a facile amidation process, and then AuNPs were electrodeposited onto the surface of dsDNA-GO. The morphology, conductivity and interaction of the as-prepared nanocomposites were characterized by scanning electron microscopy, cyclic voltammetry, electrochemical impedance spectroscopy (EIS), Raman and Fourier transform infrared spectroscopy. The thrombin-binding aptamer (TBA) was conjugated to AuNPs via gold-thiol chemistry to construct electrochemical aptasensing platform, and the specific recognition between TBA and thrombin was monitored by EIS. Under optimum conditions, thrombin could be quantified in a wide range of 0.1-100nM (R(2)=0.9960) with low detection limit of 0.06nM (S/N=3).
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Affiliation(s)
- Yu Li
- Department of Chemistry, Shanghai University, Shanghai 200444, PR China
| | - Qi Wang
- Department of Chemistry, Shanghai University, Shanghai 200444, PR China
| | - Yuting Zhang
- Department of Chemistry, Shanghai University, Shanghai 200444, PR China
| | - Dongmei Deng
- Shanghai Key Laboratory of High Temperature Superconductors, Department of Physics, Shanghai University, Shanghai 200444, PR China
| | - Haibo He
- Department of Chemistry, Shanghai University, Shanghai 200444, PR China
| | - Liqiang Luo
- Department of Chemistry, Shanghai University, Shanghai 200444, PR China; Shanghai Key Laboratory of High Temperature Superconductors, Department of Physics, Shanghai University, Shanghai 200444, PR China.
| | - Zhenxin Wang
- State Key Laboratory of Electroanalytical Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, PR China.
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De Rache A, Kejnovská I, Buess-Herman C, Doneux T. Electrochemical and circular dichroism spectroscopic evidence of two types of interaction between [Ru(NH3)6]3+ and an elongated thrombin binding aptamer G-quadruplex. Electrochim Acta 2015. [DOI: 10.1016/j.electacta.2015.05.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Mahalingam S, Xu Z, Edirisinghe M. Antibacterial Activity and Biosensing of PVA-Lysozyme Microbubbles Formed by Pressurized Gyration. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:9771-9780. [PMID: 26307462 DOI: 10.1021/acs.langmuir.5b02005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this work, the biosensing and antibacterial capabilities of PVA-lysozyme microbubbles have been explored. Gas-filled PVA-lysozyme microbubbles with and without gold nanoparticles in the diameter range of 10 to 250 μm were produced using a single-step pressurized gyration process. Fluorescence microscopy showed the integration of gold nanoparticles on the shell of the microbubbles. Microbubbles prepared with gold nanoparticles showed greater optical extinction values than those without gold nanoparticles, and these values increased with the concentration of the gold nanoparticles. Both types of microbubbles showed antibacterial activity against Gram-negative Escherichia coli (E. coli), with the bubbles containing the gold nanoparticles performing better than the former. The conjugation of the microbubbles with alkaline phosphatase allowed the detection of pesticide paraoxon in aqueous solution, and this demonstrates the biosensing capabilities of these microbubbles.
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Affiliation(s)
| | - Zewen Xu
- Department of Mechanical Engineering, University College London , Torrington Place, London WC1E 7JE, U.K
| | - Mohan Edirisinghe
- Department of Mechanical Engineering, University College London , Torrington Place, London WC1E 7JE, U.K
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Aptameric Recognition-Modulated Electroactivity of Poly(4-Styrenesolfonic Acid)-Doped Polyaniline Films for Single-Shot Detection of Tetrodotoxin. SENSORS 2015; 15:22547-60. [PMID: 26370994 PMCID: PMC4610592 DOI: 10.3390/s150922547] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 08/31/2015] [Indexed: 11/23/2022]
Abstract
The work being reported is the first electrochemical sensor for tetrodotoxin (TTX). It was developed on a glassy carbon electrodes (C) that was modified with poly(4-styrenesolfonic acid)-doped polyaniline film (PANI/PSSA). An amine-end functionalized TTX-binding aptamer, 5′-NH2-AAAAATTTCACACGGGTGCCTCGGCTGTCC-3′ (NH2-Apt), was grafted via covalent glutaraldehyde (glu) cross-linking. The resulting aptasensor (C//PANI+/PSSA-glu-NH2-Apt) was interrogated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in sodium acetate buffer (NaOAc, pH 4.8) before and after 30 min incubation in standard TTX solutions. Both CV and EIS results confirmed that the binding of the analyte to the immobilized aptamer modulated the electrochemical properties of the sensor: particularly the charge transfer resistance (Rct) of the PANI+/PSSA film, which served as a signal reporter. Based on the Rct calibration curve of the TTX aptasensor, the values of the dynamic linear range (DLR), sensitivity and limit of detection (LOD) of the sensor were determined to be 0.23–1.07 ng·mL−1 TTX, 134.88 ± 11.42 Ω·ng·mL−1 and 0.199 ng·mL−1, respectively. Further studies are being planned to improve the DLR as well as to evaluate selectivity and matrix effects in real samples.
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Johari-Ahar M, Rashidi MR, Barar J, Aghaie M, Mohammadnejad D, Ramazani A, Karami P, Coukos G, Omidi Y. An ultra-sensitive impedimetric immunosensor for detection of the serum oncomarker CA-125 in ovarian cancer patients. NANOSCALE 2015; 7:3768-79. [PMID: 25644549 DOI: 10.1039/c4nr06687a] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Effective treatment of ovarian cancer depends upon the early detection of the malignancy. Here, we report on the development of a new nanostructured immunosensor for early detection of cancer antigen 125 (CA-125). A gold electrode was modified with mercaptopropionic acid (MPA), and then consecutively conjugated with silica coated gold nanoparticles (AuNP@SiO2), CdSe quantum dots (QDs) and anti-CA-125 monoclonal antibody (mAb). The engineered MPA|AuNP@SiO2|QD|mAb immunosensor was characterised using transmission electron microscopy (TEM), atomic force microscopy (AFM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Successive conjugation of AuNP@SiO2, CdSe QD and anti-CA-125 mAb onto the gold electrode resulted in sensitive detection of CA-125 with a limit of detection (LOD) of 0.0016 U mL(-1) and a linear detection range (LDR) of 0-0.1 U mL(-1). Based on the high sensitivity and specificity of the immunosensor, we propose this highly stable and reproducible biosensor for the early detection of CA-125.
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Affiliation(s)
- M Johari-Ahar
- Research Centre for Pharmaceutical Nanotechnology, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran.
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Lv Z, Liu J, Bai W, Yang S, Chen A. A simple and sensitive label-free fluorescent approach for protein detection based on a Perylene probe and aptamer. Biosens Bioelectron 2014; 64:530-4. [PMID: 25310484 DOI: 10.1016/j.bios.2014.09.095] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2014] [Revised: 09/30/2014] [Accepted: 09/30/2014] [Indexed: 01/11/2023]
Abstract
Highly sensitive detection of proteins is of great importance for effective clinical diagnosis and biomedical research. However, so far most detection methods rely on antibody-based immunoassays and are usually laborious and time-consuming with poor sensitivity. Here, we developed a simple and ultra-sensitive method to detect a biomarker protein-thrombin by taking advantage of the fluorescent probe Perylene tetracarboxylic acid diimide (PTCDI) derivatives and thrombin aptamer. The water-soluble dye PTCDI shows strong fluorescence in buffer solution for the existence of free dye monomer, but becomes weak after aggregation through self-assembly on nucleic acid aptamer. In the presence of thrombin, it specifically binds to thrombin aptamer which causes the conformational transition between aptamer and PTCDI and results in a significant fluorescence recovery. The results showed that as low as 40 pM of thrombin could be detected by this method. The high sensitivity of the developed sensing system mainly attributes to the ultra-sensitivity of the fluorescence intensity changes of PTCDI. With the specificity of aptamer, the assay exhibited high selectivity for thrombin against three other proteins (bovine serum albumin, lysozyme, mouse IgG) and 1% diluted fetal bovine serum. The detection method might be extended to sensitive detection of a variety of proteins for its advantages of isothermal conditions required, simple and rapid without multiple separation and washing steps.
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Affiliation(s)
- Zhenzhen Lv
- Institute of Quality Standards and Testing Technology for Agro-products, Key Laboratory of Agro-product Quality and Safety, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China; College of Food Science, Sichuan Agricultural University, Ya'an 625014, China
| | - Jinchuan Liu
- Institute of Quality Standards and Testing Technology for Agro-products, Key Laboratory of Agro-product Quality and Safety, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Wenhui Bai
- Institute of Quality Standards and Testing Technology for Agro-products, Key Laboratory of Agro-product Quality and Safety, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Shuming Yang
- Institute of Quality Standards and Testing Technology for Agro-products, Key Laboratory of Agro-product Quality and Safety, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China
| | - Ailiang Chen
- Institute of Quality Standards and Testing Technology for Agro-products, Key Laboratory of Agro-product Quality and Safety, Chinese Academy of Agricultural Sciences, Beijing 100081, China; Key Laboratory of Agri-food Quality and Safety, Ministry of Agriculture, Beijing 100081, China.
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16
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Kurtulus O, Daggumati P, Seker E. Molecular release from patterned nanoporous gold thin films. NANOSCALE 2014; 6:7062-71. [PMID: 24842586 DOI: 10.1039/c4nr01288g] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Nanostructured materials have shown significant potential for biomedical applications that require high loading capacity and controlled release of drugs. Nanoporous gold (np-Au), produced by an alloy corrosion process, is a promising novel material that benefits from compatibility with microfabrication, tunable pore morphology, electrical conductivity, well-established gold-thiol conjugate chemistry, and biocompatibility. While np-Au's non-biological applications are abundant, its performance in the biomedical field is nascent. In this work, we employ a combination of techniques including nanoporous thin film synthesis, quantitative electron microscopy, fluorospectrometry, and electrochemical surface characterization to study loading capacity and molecular release kinetics as a function of film properties and discuss underlying mechanisms. The sub-micron-thick sputter-coated nanoporous gold films provide small-molecule loading capacities up to 1.12 μg cm(-2) and molecular release half-lives between 3.6 hours to 12.8 hours. A systematic set of studies reveals that effective surface area of the np-Au thin films on glass substrates plays the largest role in determining loading capacity. The release kinetics on the other hand depends on a complex interplay of micro- and nano-scale morphological features.
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Affiliation(s)
- Ozge Kurtulus
- Department of Chemical Engineering and Materials Science, University of California, Davis, CA 95616, USA
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Sinha B, Ramulu TS, Kim KW, Venu R, Lee JJ, Kim CG. Planar Hall magnetoresistive aptasensor for thrombin detection. Biosens Bioelectron 2014; 59:140-4. [PMID: 24727201 DOI: 10.1016/j.bios.2014.03.021] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 03/04/2014] [Accepted: 03/11/2014] [Indexed: 10/25/2022]
Abstract
The use of aptamer-based assays is an emerging and attractive approach in disease research and clinical diagnostics. A sensitive aptamer-based sandwich-type sensor is presented to detect human thrombin using a planar Hall magnetoresistive (PHR) sensor in cooperation with superparamagnetic labels. A PHR sensor has the great advantages of a high signal-to-noise ratio, a small offset voltage and linear response in the low-field region, allowing it to act as a high-resolution biosensor. In the system presented here, the sensor has an active area of 50 µm × 50 µm with a 10-nm gold layer deposited onto the sensor surface prior to the binding of thiolated DNA primary aptamer. A polydimethylsiloxane well of 600-µm radius and 1-mm height was prepared around the sensor surface to maintain the same specific area and volume for each sensor. The sensor response was traced in real time upon the addition of streptavidin-functionalized magnetic labels on the sensor. A linear response to the thrombin concentration in the range of 86 pM-8.6 µM and a lower detection limit down to 86 pM was achieved by the proposed present method with a sample volume consumption of 2 µl. The proposed aptasensor has a strong potential for application in clinical diagnosis.
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Affiliation(s)
- B Sinha
- Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, South Korea
| | - T S Ramulu
- Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, South Korea; Department of Emerging Materials, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, South Korea
| | - K W Kim
- Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, South Korea; Department of Emerging Materials, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, South Korea
| | - R Venu
- Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, South Korea; Department of Emerging Materials, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, South Korea
| | - J J Lee
- Nano-Mechanical Systems Research Division, Korea Institute of Machinery & Materials, Daejeon 305-600, South Korea
| | - C G Kim
- Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, South Korea; Department of Emerging Materials, Daegu Gyeongbuk Institute of Science and Technology, Daegu 711-873, South Korea.
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Li Y, Zhang J, Huang X, Wang T. Construction and direct electrochemistry of orientation controlled laccase electrode. Biochem Biophys Res Commun 2014; 446:201-5. [PMID: 24583131 DOI: 10.1016/j.bbrc.2014.02.084] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 02/19/2014] [Indexed: 10/25/2022]
Abstract
A laccase has multiple redox centres. Chemisorption of laccases on a gold electrode through a polypeptide tag introduced at the protein surface provides an isotropic orientation of laccases on the Au surface, which allows the orientation dependent study of the direct electrochemistry of laccase. In this paper, using genetic engineering technology, two forms of recombinant laccase which has Cys-6×His tag at the N or C terminus were generated. Via the Au-S linkage, the recombinant laccase was assembled orientationally on gold electrode. A direct electron transfer and a bioelectrocatalytic activity toward oxygen reduction were observed on the two orientation controlled laccase electrodes, but their electrochemical behaviors were found to be quite different. The orientation of laccase on the gold electrode affects both the electron transfer pathway and the electron transfer efficiency of O2 reduction. The present study is helpful not only to the in-depth understanding of the direct electrochemistry of laccase, but also to the development of laccase-based biofuel cells.
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Affiliation(s)
- Ying Li
- Key Laboratory of Colloid & Interface Chemistry of the Education Ministry of China, Shandong University, Jinan 250100, PR China
| | - Jiwei Zhang
- State Key Laboratory of Microbial Technology of China, Shandong University, Jinan 250100, PR China
| | - Xirong Huang
- Key Laboratory of Colloid & Interface Chemistry of the Education Ministry of China, Shandong University, Jinan 250100, PR China; State Key Laboratory of Microbial Technology of China, Shandong University, Jinan 250100, PR China.
| | - Tianhong Wang
- State Key Laboratory of Microbial Technology of China, Shandong University, Jinan 250100, PR China.
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Römhildt L, Pahlke C, Zörgiebel F, Braun HG, Opitz J, Baraban L, Cuniberti G. Patterned biochemical functionalization improves aptamer-based detection of unlabeled thrombin in a sandwich assay. ACS APPLIED MATERIALS & INTERFACES 2013; 5:12029-35. [PMID: 24171544 DOI: 10.1021/am4038245] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Here we propose a platform for the detection of unlabeled human α-thrombin down to the picomolar range in a fluorescence-based aptamer assay. In this concept, thrombin is captured between two different thrombin binding aptamers, TBA1 (15mer) and TBA2 (29mer), each labeled with a specific fluorescent dye. One aptamer is attached to the surface, the second one is in solution and recognizes surface-captured thrombin. To improve the limit of detection and the comparability of measurements, we employed and compared two approaches to pattern the chip substrate-microcontact printing of organosilanes onto bare glass slides, and controlled printing of the capture aptamer TBA1 in arrays onto functionalized glass substrates using a nanoplotter device. The parallel presence of functionalized and control areas acts as an internal reference. We demonstrate that both techniques enable the detection of thrombin concentrations in a wide range from 0.02 to 200 nM with a detection limit at 20 pM. Finally, the developed method could be transferred to any substrate to probe different targets that have two distinct possible receptors without the need for direct target labeling.
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Affiliation(s)
- Lotta Römhildt
- Institute for Materials Science and Max Bergmann Center of Biomaterials and §Center for Advancing Electronics Dresden, TU Dresden , 01062 Dresden, Germany
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20
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One-step porous gold fabricated electrode for electrochemical impedance spectroscopy immunosensor detection. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.08.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Hasanzadeh M, Shadjou N, Eskandani M, de la Guardia M, Omidinia E. Electrochemical nano-immunosensing of effective cardiac biomarkers for acute myocardial infarction. Trends Analyt Chem 2013. [DOI: 10.1016/j.trac.2013.04.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Kashefi-Kheyrabadi L, Mehrgardi MA. Aptamer-based electrochemical biosensor for detection of adenosine triphosphate using a nanoporous gold platform. Bioelectrochemistry 2013; 94:47-52. [PMID: 23803470 DOI: 10.1016/j.bioelechem.2013.05.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 05/26/2013] [Accepted: 05/29/2013] [Indexed: 10/26/2022]
Abstract
In spite of the promising applications of aptamers in the bioassays, the development of aptamer-based electrochemical biosensors with the improved limit of detection has remained a great challenge. A strategy for the amplification of signal, based on application of nanostructures as platforms for the construction of an electrochemical adenosine triphosphate (ATP) aptasensor, is introduced in the present manuscript. A sandwich assay is designed by immobilizing a fragment of aptamer on a nanoporous gold electrode (NPGE) and its association to second fragment in the presence of ATP. Consequently, 3, 4-diaminobenzoic acid (DABA), as a molecular reporter, is covalently attached to the amine-label of the second fragment, and the direct oxidation signal of DABA is followed as the analytical signal. The sensor can detect the concentrations of ATP as low as submicromolar scales. Furthermore, 3.2% decrease in signal is observed by keeping the aptasensor at 4 °C for a week in buffer solution, implying a desirable stability. Moreover, analog nucleotides, including GTP, UTP and CTP, do not show serious interferences and this sensor easily detects its target in deproteinized human blood plasma.
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Abstract
Nanoporous gold prepared by dealloying Au:Ag alloys has recently become an attractive material in the field of analytical chemistry. This conductive material has an open, 3D porous framework consisting of nanosized pores and ligaments with surface areas that are 10s to 100s of times larger than planar gold of an equivalent geometric area. The high surface area coupled with an open pore network makes nanoporous gold an ideal support for the development of chemical sensors. Important attributes include conductivity, high surface area, ease of preparation and modification, tunable pore size, and a bicontinuous open pore network. In this paper, the fabrication, characterization, and applications of nanoporous gold in chemical sensing are reviewed specifically as they relate to the development of immunosensors, enzyme-based biosensors, DNA sensors, Raman sensors, and small molecule sensors.
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24
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Application Progress of Nanoporous Gold in Analytical Chemistry. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2013. [DOI: 10.1016/s1872-2040(13)60624-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Thomas JP, Zhao L, Ding K, Heinig NF, Leung KT. Near-surface oxidized sulfur modifications and self-assembly of thiol-modified aptamer on Au thin film substrates influenced by piranha treatment. ACS APPLIED MATERIALS & INTERFACES 2012; 4:5945-5948. [PMID: 23039103 DOI: 10.1021/am301589k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Self-assembly of thiol-modified oligonucleotides on Au films has great importance for biosensor applications. Prior to the self-assembly, a piranha treatment (PT) is commonly used to clean the Au surface. Here we report that near-surface oxidized sulfur modifications on Au thin films by PT for longer than 60 s have serious effects on the self-assembled monolayer (SAM) formation of thiol-modified single-stranded thrombin binding aptamer (s-TBA), and a PT time of 10-30 s is optimal for s-TBA SAM formation. These results have important implication to SAM formation of biomolecules, especially for the thiol-modified ones where a careful consideration of this key step could significantly enhance the SAM formation and biosensor performance.
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Affiliation(s)
- Joseph P Thomas
- WATLab and Department of Chemistry, University of Waterloo , Waterloo, Ontario N2L3G1, Canada
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Advances in polymeric and inorganic vectors for nonviral nucleic acid delivery. Ther Deliv 2012; 2:493-521. [PMID: 22826857 DOI: 10.4155/tde.11.14] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Nonviral systems for nucleic acid delivery offer a host of potential advantages compared with viruses, including reduced toxicity and immunogenicity, increased ease of production and less stringent vector size limitations, but remain far less efficient than their viral counterparts. In this article we review recent advances in the delivery of nucleic acids using polymeric and inorganic vectors. We discuss the wide range of materials being designed and evaluated for these purposes while considering the physical requirements and barriers to entry that these agents face and reviewing recent novel approaches towards improving delivery with respect to each of these barriers. Furthermore, we provide a brief overview of past and ongoing nonviral gene therapy clinical trials. We conclude with a discussion of multifunctional nucleic acid carriers and future directions.
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Qiu H, Dong X, Huang X. Design of nanoporous metals with bimodal pore size distributions for enhanced biosensing. NANOSCALE 2012; 4:4492-4497. [PMID: 22538347 DOI: 10.1039/c2nr30460k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Nanoporous gold (np-Au) has shown great potential in catalysis, plasmonics, sensing, etc. In this work, by two-step dealloying a well-designed AuAgAl ternary precursor alloy, np-Au with bimodal ligament/pore size distributions is successfully fabricated. The first dealloying in HCl solution removes Al and generates a nanoporous AuAg alloy which would be mildly annealed at 200 °C for 30 min to homogenize the alloy ligament and enlarge the ligament/pore size. Next, the nanoporous AuAg alloy is further dealloyed in a HNO(3) solution to etch Ag and fabricate np-Au with a hierarchical microstructure. This novel bimodal np-Au is demonstrated to exhibit enhanced electrocatalytic activity towards H(2)O(2) reduction and be a better support for the fabrication of an oxidase-based biosensor compared with normal np-Au, with a uniform pore/ligament size of 30-40 nm. In a proof-of-concept study, a sensitive glucose biosensor with a linear range up to 21 mM is fabricated by immobilization of glucose oxidase on the bimodal np-Au.
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Affiliation(s)
- Huajun Qiu
- School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China.
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Lee SJ, Tatavarty R, Gu MB. Electrospun polystyrene-poly(styrene-co-maleic anhydride) nanofiber as a new aptasensor platform. Biosens Bioelectron 2012; 38:302-7. [PMID: 22776178 DOI: 10.1016/j.bios.2012.06.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 06/02/2012] [Accepted: 06/06/2012] [Indexed: 11/20/2022]
Abstract
Here, we report the use of an aptamer-immobilized electrospun polystyrene-poly(styrene-co-maleic anhydride) (PS-PSMA) nanofiber as a new aptasensor platform for protein detection. Two thrombin-binding aptamers (TBA29 and TBA15) were used as a model platform to facilitate efficient detection of thrombin in a sandwich manner. Thrombin concentration was measured by fluorescence microscopy and spectroscopy, in which aptamers were labeled with either fluorescein dye or quantum dots. The results indicated that thrombin was captured uniformly on the surface of the nanofiber. Using this sandwich-type biosensor, the minimum detectable concentration of thrombin was 10 pM, with a dynamic range of 0.1-50 nM, when quantum dots were used for labeling. In contrast, the limit of detection was 1 nM, with a dynamic range of 10-200 nM, when using fluorescein dye labeling. This aptamers-on-nanofiber-based biosensor showed 2500-fold higher sensitivity than a 96-microwell plate format, attributed mainly to the large surface area of the nanofibers. In addition, this novel platform also exhibited similar high sensitivity in the detection of exogenously added thrombin in diluted human serum. This aptamers-on-nanofiber system, which is competitive with other sensing platforms and clinically meaningful in terms of its detection limit, is expected to be useful for the detection of various other targets because of its ease of application and manipulation.
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Affiliation(s)
- Su Jin Lee
- College of Life Sciences and Biotechnology, Korea University Anam-Dong, Seongbuk-Gu, Seoul 136-701, Republic of Korea
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Ebrahimi M, Johari-Ahar M, Hamzeiy H, Barar J, Mashinchian O, Omidi Y. Electrochemical impedance spectroscopic sensing of methamphetamine by a specific aptamer. BIOIMPACTS : BI 2012; 2:91-5. [PMID: 23678446 DOI: 10.5681/bi.2012.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/03/2012] [Revised: 04/15/2012] [Accepted: 04/20/2012] [Indexed: 12/23/2022]
Abstract
INTRODUCTION Electrochemical impedance spectroscopy (EIS) is a simple and highly sensitive technique that can be used for evaluation of the aptamer-target interaction even in a label-free approach. METHODS To pursue the effectiveness of EIS, in the current study, the folding properties of specific aptamer for methamphetamine (METH) (i.e., aptaMETH) were evaluated in the presence of METH and amphetamine (Amph). Folded and unfolded aptaMETH was mounted on the gold electrode surface and the electron charge transfer was measured by EIS. RESULTS The Ret of methamphetamine-aptaMETH was significantly increased in comparison with other folding conditions, indicating specific detection of METH by aptaMETH. CONCLUSION Based on these findings, methamphetamine-aptaMETH on the gold electrode surface displayed the most interfacial electrode resistance and thus the most folding situation. This clearly indicates that the aptaMETH can profoundly and specifically pinpoint METH; as a result we suggest utilization of this methodology for fast and cost-effective identification of METH.
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Affiliation(s)
- Mohsen Ebrahimi
- Department of Toxicology and Pharmacology, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran ; Students' Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran ; Research Center for Pharmaceutical Nanotechnology, Faculty of Pharmacy, Tabriz University of Medical Sciences, Tabriz, Iran
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Scanlon MD, Salaj-Kosla U, Belochapkine S, MacAodha D, Leech D, Ding Y, Magner E. Characterization of nanoporous gold electrodes for bioelectrochemical applications. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:2251-2261. [PMID: 22004670 DOI: 10.1021/la202945s] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The high surface areas of nanostructured electrodes can provide for significantly enhanced surface loadings of electroactive materials. The fabrication and characterization of nanoporous gold (np-Au) substrates as electrodes for bioelectrochemical applications is described. Robust np-Au electrodes were prepared by sputtering a gold-silver alloy onto a glass support and subsequent dealloying of the silver component. Alloy layers were prepared with either a uniform or nonuniform distribution of silver and, post dealloying, showed clear differences in morphology on characterization with scanning electron microscopy. Redox reactions under kinetic control, in particular measurement of the charge required to strip a gold oxide layer, provided the most accurate measurements of the total electrochemically addressable electrode surface area, A(real). Values of A(real) up to 28 times that of the geometric electrode surface area, A(geo), were obtained. For diffusion-controlled reactions, overlapping diffusion zones between adjacent nanopores established limiting semi-infinite linear diffusion fields where the maximum current density was dependent on A(geo). The importance of measuring the surface area available for the immobilization was determined using the redox protein, cyt c. The area accessible to modification by a biological macromolecule, A(macro), such as cyt c was reduced by up to 40% compared to A(real), demonstrating that the confines of some nanopores were inaccessible to large macromolecules due to steric hindrances. Preliminary studies on the preparation of np-Au electrodes modified with osmium redox polymer hydrogels and Myrothecium verrucaria bilirubin oxidase (MvBOD) as a biocathode were performed; current densities of 500 μA cm(-2) were obtained in unstirred solutions.
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Affiliation(s)
- Micheál D Scanlon
- Department of Chemical and Environmental Sciences & Materials and Surface Science Institute, University of Limerick, Limerick, Ireland
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Prabhakar N, Matharu Z, Malhotra BD. Polyaniline Langmuir-Blodgett film based aptasensor for ochratoxin A detection. Biosens Bioelectron 2011; 26:4006-11. [PMID: 21514815 DOI: 10.1016/j.bios.2011.03.014] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Revised: 03/16/2011] [Accepted: 03/17/2011] [Indexed: 11/25/2022]
Abstract
Ochratoxin A (OTA) produced by Aspergillus Ochraceus and Penicillium verrucosum is a very dangerous toxin due to its toxic effects in human beings and its presence in a wide range of food products and cereals. A Langmuir-Blodgett (polyaniline (PANI)-stearic acid (SA)) film based highly sensitive and robust impedimetric aptasensor has been developed for ochratoxin A (OTA) detection. DNA Aptamer (Apt-DNA) specific to OTA has been covalently immobilized onto mixed Langmuir-Blodgett (LB) monolayer comprising of PANI-SA deposited onto indium tin-oxide (ITO) coated glass plates. This Apt-DNA/PANI-SA/ITO aptaelectrode has been characterized using scanning electron microscopy, Fourier transform-infrared spectroscopy, contact angle measurements, cyclic voltammetry and electrochemical impedance spectroscopy, respectively. The Apt-DNA/PANI-SA/ITO aptasensor shows detection of OTA by electrochemical impedance spectroscopy in the linear range of 0.0001 μg/ml (0.1 ng/ml) to 0.01 μg/ml (10 ng/ml) and 1 μg/ml-25 μg/ml with detection limit of 0.1 ng/ml in 15 min. The Apt-DNA/PANI-SA/ITO aptasensor can be reused ∼13 times. The binding or affinity constant (K(a)) of aptamer with OTA, calculated using Langmuir adsorption isotherm, is found be 1.21×10(7) M(-1).
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Affiliation(s)
- Nirmal Prabhakar
- Department of Science and Technology Centre on Biomolecular Electronics, Biomedical Instrumentation Section, Materials Physics & Engineering Division, National Physical Laboratory (Council of Scientific & Industrial Research), Dr. K. S. Krishnan Marg, New Delhi 110012, India
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Radi AE. Electrochemical Aptamer-Based Biosensors: Recent Advances and Perspectives. INTERNATIONAL JOURNAL OF ELECTROCHEMISTRY 2011; 2011:1-17. [DOI: 10.4061/2011/863196] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023] Open
Abstract
This paper reviews the advancements of a wide range of electrochemical aptamer-based biosensors, electrochemical aptasensors, for target analytes monitoring. Methods for immobilizing aptamers onto an electrode surface are discussed. Aptasensors are presented according to their detection strategies. Many of these are simply electrochemical, aptamer-based equivalents of traditional immunochemical approaches, sandwich and competition assays employing electroactive signaling moieties. Others, exploiting the unusual physical properties of aptamers, are signal-on (positive readout signal) and signal-off (negative readout signal) aptasensors based on target binding-induced conformational change of aptamers. Aptamer label-free devices are also discussed.
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Affiliation(s)
- Abd-Elgawad Radi
- Department of Chemistry, Faculty of Science, Mansoura University, Dumyat 34517, Egypt
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Velusamy V, Arshak K, Yang CF, Yu L, Korostynska O, Adley C. Comparison between DNA Immobilization Techniques on a Redox Polymer Matrix. ACTA ACUST UNITED AC 2011. [DOI: 10.4236/ajac.2011.23048] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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