Characterization of the barrier layer of nanoporous alumina films prepared using two different contact configurations

Koh, Guiwan; Agarwal, Shuchi; Cheow, Pui-Sze; Toh, Chee-Seng

doi:10.1016/j.electacta.2006.08.065

Cited by 18 publications

(14 citation statements)

References 26 publications

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“…In order to control the potential of working electrode accurately, three-electrode system is employed in the experiments. Three-electrode system has been widely used in the biochips and biomolecular sensors (Rai et al 2012b;Koh et al 2007). The working electrode (anode) and counter electrode (cathode) have Pt central core wrapped with a layer of PTFE, the diameter of Pt core and coating PTFE layer are 0.5 mm and 6.0 mm, respectively.…”

Section: Experimental Methodsmentioning

confidence: 99%

Current characteristic signals of aqueous solution transferring through microfluidic channel under non-continuous DC electric field

Wang

Gao

et al. 2014

AIP Advances

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The surface effect is becoming apparently significant as the miniaturization of fluidic devices. In the micro/nanochannel fluidics, the electrode surface effects have the same important influence on the current signals as the channel surface effects. In this paper, when aqueous solution are driven with non-continuous DC electric field force, the characteristics of current signals of the fluid transferring through microfluidic channel are systematically studied. Six modes of current signal are summarized, and some new significant phenomena are found, e.g. there exists a critical voltage at which the steady current value equals to zero; the absolute value of the steady current decreases at first, however, it increases with the external voltage greater than the critical voltage as the electrode area ratio of cathode and anode is 10 and 20; the critical voltage increases with the enhancing of electrode area ratio of cathode and anode and solution pH, while it decreases with the raising of ion concentration. Finally, the microscopic mechanism of the electrode surface charge effects is discussed preliminarily. The rules will be helpful for detecting and manipulating single biomolecules in the micro/nanofluidic chips and biosensors.

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Section: Experimental Methodsmentioning

confidence: 99%

Current characteristic signals of aqueous solution transferring through microfluidic channel under non-continuous DC electric field

Wang

Gao

et al. 2014

AIP Advances

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“…Anodization using the surface contact anodization method was described elsewhere. 22 Etching in 3% H 3 PO 4 for 15 min was conducted in order to broaden the size of alumina nanopore channels. Longer etching time is not desirable as it would cause membrane disintegration.…”

Section: Methodsmentioning

confidence: 99%

Membrane-Based Electrochemical Nanobiosensor for Escherichia coli Detection and Analysis of Cells Viability

Cheng

Lau

Chow

et al. 2011

Environ. Sci. Technol.

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A sensitive and selective membrane-based electrochemical nanobiosensor is developed for specific quantitative label-free detection of Escherichia coli (E. coli) cells and analysis of viable but nonculturable (VBNC) E. coli cells which remain mostly undetected using current methods. The sensing mechanism relies on the blocking of nanochannels of a nanoporous alumina-membrane modified electrode, upon the formation of immune complexes at the nanoporous membrane. The resulting obstacle to diffusive mass transfer of a redox probe in the analysis solution to the underlying platinum electrode reduces the Faradaic signal response of the biosensor, measured using cyclic voltammetry. Antibody loading under conditions of varying antibody concentrations and pHs are optimized. The biosensor gives a low detection limit of 22 cfu mL(-1) (R(2) = 0.999) over a wide linear working range of 10 to 10(6) cfu mL(-1). It is specific toward E. coli with minimal cross-reactivity to two other pathogenic bacteria (commonly found in waters). Relative standard deviation (RSD) for triplicate measurements of 2.5% indicates reasonably useful level of reproducibility. Differentiation of live, VBNC, and dead cells are carried out after the cell capture and quantitation step, by simple monitoring of the cells' enzyme activity using the same redox probe in the analysis solution, in the presence of glucose.

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“…Pt wires were embedded in micropipette tips and sputter coated with high‐purity Al. Al‐coated tips were etched using the technique developed by the same group known as surface contact anodization . The applicability of these membrane‐modified electrodes was validated by quantifying the antigen–antibody binding within the pores via the change in Faradaic current of ferrocenemethanol, a redox species added in solution.…”

Section: Naa‐based Biosensing Platforms For Biomarker Detectionmentioning

confidence: 99%

Advances in Nanoporous Anodic Alumina‐Based Biosensors to Detect Biomarkers of Clinical Significance: A Review

Rajeev¹,

Prieto‐Simón

Marsal

et al. 2017

Adv Healthcare Materials

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There is a strong and growing demand for compact, portable, rapid, and low-cost devices to detect biomarkers of interest in clinical and point-of-care diagnostics. Such devices aid in early diagnosis of diseases without the need to rely on expensive and time-consuming large instruments in dedicated laboratories. Over the last decade, numerous biosensors have been developed for detection of a wide range of clinical biomarkers including proteins, nucleic acids, growth factors, and bacterial enzymes. Various transduction techniques have been reported based on biosensor technology that deliver substantial advances in analytical performance, including sensitivity, reproducibility, selectivity, and speed for monitoring a wide range of human health conditions. Nanoporous anodic alumina (NAA) has been used extensively for biosensing applications due to its inherent optical and electrochemical properties, ease of fabrication, large surface area, tunable properties, and high stability in aqueous environment. This review focuses on NAA-based biosensing systems for detection of clinically significant biomarkers using various detection techniques with the main focus being on electrochemical and optical transduction methods. The review covers an overview of the importance of biosensors for biomarkers detection, general (surface and structural) properties and fabrication of NAA, and NAA-based biomarker sensing systems.

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Characterization of the barrier layer of nanoporous alumina films prepared using two different contact configurations

Cited by 18 publications

References 26 publications

Current characteristic signals of aqueous solution transferring through microfluidic channel under non-continuous DC electric field

Current characteristic signals of aqueous solution transferring through microfluidic channel under non-continuous DC electric field

Membrane-Based Electrochemical Nanobiosensor for Escherichia coli Detection and Analysis of Cells Viability

Advances in Nanoporous Anodic Alumina‐Based Biosensors to Detect Biomarkers of Clinical Significance: A Review

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