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Electrochemical Discrimination of Salbutamol from Its Excipients in Ventolin TM at Nanoporous Gold Microdisc Arrays. SENSORS 2021; 21:s21123975. [PMID: 34207616 PMCID: PMC8226559 DOI: 10.3390/s21123975] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/23/2021] [Accepted: 05/31/2021] [Indexed: 02/02/2023]
Abstract
The emergence of specific drug–device combination products in the inhalable pharmaceutical industry demands more sophistication of device functionality in the form of an embedded sensing platform to increase patient safety and extend patent coverage. Controlling the nebuliser function at a miniaturised, integrated electrochemical sensing platform with rapid response time and supporting novel algorithms could deliver such a technology offering. Development of a nanoporous gold (NPG) electrochemical sensor capable of creating a unique fingerprint signal generated by inhalable pharmaceuticals provided the impetus for our study of the electrooxidation of salbutamol, which is the active bronchodilatory ingredient in VentolinTM formulations. It was demonstrated that, at NPG-modified microdisc electrode arrays, salbutamol is distinguishable from the chloride excipient present at 0.0154 M using linear sweep voltammetry and can be detected amperometrically. In contrast, bare gold microdisc electrode arrays cannot afford such discrimination, as the potential for salbutamol oxidation and chloride adsorption reactions overlap. The discriminative power of NPG originates from the nanoconfinement effect for chloride in the internal pores of NPG, which selectively enhances the electron transfer kinetics of this more sluggish reaction relative to that of the faster, diffusion-controlled salbutamol oxidation. Sensing was performed at a fully integrated three-electrode cell-on-chip using Pt as a quasi-reference electrode.
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From Chip Size to Wafer-Scale Nanoporous Gold Reliable Fabrication Using Low Currents Electrochemical Etching. NANOMATERIALS 2020; 10:nano10112321. [PMID: 33238541 PMCID: PMC7700230 DOI: 10.3390/nano10112321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 11/14/2020] [Accepted: 11/16/2020] [Indexed: 11/21/2022]
Abstract
We report a simple, scalable route to wafer-size processing for fabrication of tunable nanoporous gold (NPG) by the anodization process at low constant current in a solution of hydrofluoric acid and dimethylformamide. Microstructural, optical, and electrochemical investigations were employed for a systematic analysis of the sample porosity evolution while increasing the anodization duration, namely the small angle X-ray scattering (SAXS) technique and electrochemical impedance spectroscopy (EIS). Whereas the SAXS analysis practically completes the scanning electronic microscopy (SEM) investigations and provides data about the impact of the etching time on the nanoporous gold layers in terms of fractal dimension and average pore surface area, the EIS analysis was used to estimate the electroactive area, the associated roughness factor, as well as the heterogeneous electron transfer rate constant. The bridge between the analyses is made by the scanning electrochemical microscopy (SECM) survey, which practically correlates the surface morphology with the electrochemical activity. The results were correlated to endorse the control over the gold film nanostructuration process deposited directly on the substrate that can be further subjected to different technological processes, retaining its properties. The results show that the anodization duration influences the surface area, which subsequently modifies the properties of NPG, thus enabling tuning the samples for specific applications, either optical or chemical.
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Wang P, Dong Y, Zhang S, Liu W, Wu Z, Chen H. Protein-resistant properties of poly(N-vinylpyrrolidone)-modified gold surfaces: The advantage of bottle-brushes over linear brushes. Colloids Surf B Biointerfaces 2019; 177:448-453. [DOI: 10.1016/j.colsurfb.2019.02.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/30/2019] [Accepted: 02/15/2019] [Indexed: 01/12/2023]
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Stine KJ. Enzyme Immobilization on Nanoporous Gold: A Review. BIOCHEMISTRY INSIGHTS 2017; 10:1178626417748607. [PMID: 29308011 PMCID: PMC5751899 DOI: 10.1177/1178626417748607] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 11/24/2017] [Indexed: 11/21/2022]
Abstract
Nanoporous gold (referred to as np-Au or NPG) has emerged over the past 10 years as a new support for enzyme immobilization. The material has appealing features of ease of preparation, tunability of pore size, high surface to volume ratio, and compatibility with multiple strategies for enzyme immobilization. The np-Au material is especially of interest for immobilization of redox enzymes for biosensor and biofuel cell applications given the ability to construct electrodes of high surface area and stability. Adjustment of the pore size of np-Au can yield enhancements in enzyme thermal stability. Glucose oxidase immobilization on np-Au has been a focus for development of glucose sensors. Immobilization of laccase and related enzymes has demonstrated the utility of np-Au for construction of biofuel cells. Np-Au has been used to immobilize other redox enzymes, enzyme conjugates for use in bioassays, and enzymes of interest for industrial processes.
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Affiliation(s)
- Keith J Stine
- Department of Chemistry and Biochemistry, Center for Nanoscience, University of Missouri–St. Louis, St. Louis, MO, USA
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5
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Fang C, Megharaj M, Naidu R. Electrochemical Studies on Self-assembled Monolayer (SAM) Upon Exposure to Anionic Surfactants: PFOA, PFOS, SDS and SDBS. ELECTROANAL 2017. [DOI: 10.1002/elan.201700108] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Cheng Fang
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE); University of Newcastle; Callaghan NSW 2308 Australia
- Global Centre for Environmental Remediation (GCER); University of Newcastle; Callaghan NSW 2308 Australia
| | - Mallavarapu Megharaj
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE); University of Newcastle; Callaghan NSW 2308 Australia
- Global Centre for Environmental Remediation (GCER); University of Newcastle; Callaghan NSW 2308 Australia
| | - Ravi Naidu
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE); University of Newcastle; Callaghan NSW 2308 Australia
- Global Centre for Environmental Remediation (GCER); University of Newcastle; Callaghan NSW 2308 Australia
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Fang C, Megharaj M, Naidu R. Electrochemical switch on-off response of a self-assembled monolayer (SAM) upon exposure to perfluorooctanoic acid (PFOA). J Electroanal Chem (Lausanne) 2017. [DOI: 10.1016/j.jelechem.2016.12.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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7
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Fanga C, Megharaj M, Naidu R. Electrochemical Detection of Thioether-Based Fluorosurfactants in Aqueous Film-Forming Foam (AFFF). ELECTROANAL 2016. [DOI: 10.1002/elan.201600724] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Cheng Fanga
- Global Centre for Environmental Remediation (GCER), ACT Building; University of Newcastle; Callaghan NSW 2308 Australia
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ACT Building; University of Newcastle; Callaghan NSW 2308 Australia
| | - Mallavarapu Megharaj
- Global Centre for Environmental Remediation (GCER), ACT Building; University of Newcastle; Callaghan NSW 2308 Australia
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ACT Building; University of Newcastle; Callaghan NSW 2308 Australia
| | - Ravi Naidu
- Global Centre for Environmental Remediation (GCER), ACT Building; University of Newcastle; Callaghan NSW 2308 Australia
- Cooperative Research Centre for Contamination Assessment and Remediation of the Environment (CRC CARE), ACT Building; University of Newcastle; Callaghan NSW 2308 Australia
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Wannapob R, Thavarungkul P, Dawan S, Numnuam A, Limbut W, Kanatharana P. A Simple and Highly Stable Porous Gold-based Electrochemical Sensor for Bisphenol A Detection. ELECTROANAL 2016. [DOI: 10.1002/elan.201600371] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Rodtichoti Wannapob
- Trace Analysis and Biosensor Research Center; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
- Center of Excellence for Innovation in Chemistry, Faculty of Science; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
- Department of Chemistry, Faculty of Science; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
| | - Panote Thavarungkul
- Trace Analysis and Biosensor Research Center; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
- Center of Excellence for Innovation in Chemistry, Faculty of Science; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
- Department of Physics, Faculty of Science; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
| | - Supaporn Dawan
- Trace Analysis and Biosensor Research Center; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
- Center of Excellence for Innovation in Chemistry, Faculty of Science; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
- Department of Chemistry, Faculty of Science; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
| | - Apon Numnuam
- Trace Analysis and Biosensor Research Center; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
- Center of Excellence for Innovation in Chemistry, Faculty of Science; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
- Department of Chemistry, Faculty of Science; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
| | - Warakorn Limbut
- Trace Analysis and Biosensor Research Center; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
- Center of Excellence for Innovation in Chemistry, Faculty of Science; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
- Department of Applied Science, Faculty of Science; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
| | - Proespichaya Kanatharana
- Trace Analysis and Biosensor Research Center; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
- Center of Excellence for Innovation in Chemistry, Faculty of Science; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
- Department of Chemistry, Faculty of Science; Prince of Songkla University; Hat Yai, Songkhla 90112 Thailand
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Zheng X, Zhang C, Bai L, Liu S, Tan L, Wang Y. Antifouling property of monothiol-terminated bottle-brush poly(methylacrylic acid)-graft-poly(2-methyl-2-oxazoline) copolymer on gold surfaces. J Mater Chem B 2015; 3:1921-1930. [DOI: 10.1039/c4tb01766h] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
A series of well-controlled bottle-brush poly(methylacrylic acid)-graft-poly(2-methyl-2-oxazoline) copolymers were grafted to gold surfaces through an in situ aminolysis reaction to reduce protein adsorption and platelet adhesion.
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Affiliation(s)
- Xiajun Zheng
- CAS Key Laboratory of Soft Matter Chemistry
- Department of Polymer Science and Engineering
- University of Science and Technology of China
- Hefei, Anhui Province, 230026
- P. R. China
| | - Chong Zhang
- CAS Key Laboratory of Soft Matter Chemistry
- Department of Polymer Science and Engineering
- University of Science and Technology of China
- Hefei, Anhui Province, 230026
- P. R. China
| | - Longchao Bai
- CAS Key Laboratory of Soft Matter Chemistry
- Department of Polymer Science and Engineering
- University of Science and Technology of China
- Hefei, Anhui Province, 230026
- P. R. China
| | - Songtao Liu
- CAS Key Laboratory of Soft Matter Chemistry
- Department of Polymer Science and Engineering
- University of Science and Technology of China
- Hefei, Anhui Province, 230026
- P. R. China
| | - Lin Tan
- CAS Key Laboratory of Soft Matter Chemistry
- Department of Polymer Science and Engineering
- University of Science and Technology of China
- Hefei, Anhui Province, 230026
- P. R. China
| | - Yanmei Wang
- CAS Key Laboratory of Soft Matter Chemistry
- Department of Polymer Science and Engineering
- University of Science and Technology of China
- Hefei, Anhui Province, 230026
- P. R. China
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Chen WY, Mei LP, Feng JJ, Yuan T, Wang AJ, Yu H. Electrochemical determination of bisphenol A with a glassy carbon electrode modified with gold nanodendrites. Mikrochim Acta 2014. [DOI: 10.1007/s00604-014-1377-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Fang C, Shapter JG, Voelcker NH, Ellis AV. Electrochemically prepared nanoporous gold as a SERS substrate with high enhancement. RSC Adv 2014. [DOI: 10.1039/c4ra01909a] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Gold films were electrochemically etched into nanoporous substrates with tuneable pore sizes down to approximately 2 nm. The SERS enhancement as a result of changes in valley and ligament widths of the nanoporous gold was investigated. Compared to the conventional de-alloyed nano-gold, the etched gold showed a lower limit of detection (2 × 10−9 M vs. 1 × 10−7 M Rhodamine 6G).
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Affiliation(s)
- Cheng Fang
- Flinders Centre for Nanoscale Science and Technology
- School of Chemical and Physical Sciences
- Flinders University
- Adelaide SA5042, Australia
| | - Joseph George Shapter
- Flinders Centre for Nanoscale Science and Technology
- School of Chemical and Physical Sciences
- Flinders University
- Adelaide SA5042, Australia
| | | | - Amanda Vera Ellis
- Flinders Centre for Nanoscale Science and Technology
- School of Chemical and Physical Sciences
- Flinders University
- Adelaide SA5042, Australia
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Synthesis of Nanoporous Gold Electrode and Its Application in Electrochemical Sensor. CHINESE JOURNAL OF ANALYTICAL CHEMISTRY 2013. [DOI: 10.1016/s1872-2040(13)60652-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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13
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Sun S, Wu P. Easy fabrication of macroporous gold films using graphene sheets as a template. ACS APPLIED MATERIALS & INTERFACES 2013; 5:3481-6. [PMID: 23521719 DOI: 10.1021/am400703v] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We demonstrate a facile new and environmentally friendly strategy to fabricate monolithic macroporous gold (MPG) films using graphene sheets as a sacrificial template. Gold nanoparticle (AuNP) decorated graphene sheets were prepared by a one-pot simultaneous reduction of graphene oxide (GO) and gold precursor (HAuCl4) by sodium citrate. Two thermal annealing methods, direct thermal annealing in air and a two-step thermal treatment (in N2 first and subsequently in air), were then employed to remove the template (graphene sheets), which can both produce macroporous structures, but with distinctly different morphologies. We additionally investigated the porosity evolution mechanism as well as the effect of graphene/Au weight ratio and annealing temperature on the nanoarchitecture. The two-step treatment has a more significant templating effect than direct thermal annealing to fabricate MPG films because of the existence of a preaggregation process of AuNPs assisted by graphene sheets in N2. Moreover, the resulting MPG films were found to exhibit excellent surface-enhanced Raman scattering (SERS) activity. Our method can be hopefully extended to the synthesis of other porous materials (such as Ag, Cu, Pt, and ceramic) and much wider applications.
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Affiliation(s)
- Shengtong Sun
- State Key Laboratory of Molecular Engineering of Polymers, Department of Macromolecular Science, Fudan University, Shanghai 200433, People's Republic of China
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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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