Regenerable Biosensor Platform:  A Total Internal Reflection Fluorescence Cell with Electrochemical Control

Asanov, Alexander; Wilson, W. William; Oldham, Philip B.

doi:10.1021/ac970805y

Cited by 141 publications

(116 citation statements)

References 12 publications

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“…The influence of an applied electric potential on the adsorption of charged macromolecules (mainly proteins) has been the subject of several previous investigations (19,20,(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44). Although most of these studies note an influence of substrate potential on adsorption, changes are typically within a factor of two or so, and to our knowledge no continuous adsorption has been reported.…”

Section: Discussionmentioning

confidence: 99%

Continuous polyelectrolyte adsorption under an applied electric potential

Ngankam

Tassel

2007

Proc. Natl. Acad. Sci. U.S.A.

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Interactions between charged macromolecules (e.g., proteins, nucleic acids, polyelectrolytes) and charged surfaces govern many natural and industrial processes. We investigate here the influence of an applied electric potential on the adsorption of charged polymers, and report the following significant result: the adsorption of certain amine side chain-containing polycations may become continuous, i.e., asymptotically linear (or nearly linear) in time over hours, upon the application of a modest anodic potential. Employing optical waveguide lightmode spectroscopy (OWLS) and an indium tin oxide (ITO) substrate, we show that asymptotic kinetics, and the adsorbed mass at the onset of the asymptotic regime, depend sensitively on polymer chemistry (in particular, side chain volume and charge location), increase with applied potential and ionic strength (conditions favoring a thicker initial layer), and are independent of bulk polymer concentration (suggesting postadsorption events to be rate limiting). X-ray photoelectron spectra reveal a suppressed polymer charge within layers formed via continuous adsorption, but no evidence of electrochemical reactions. We propose a mechanism based on polymer-polymer binding within the adsorbed layer, enabled by suppressed electrostatic repulsion and/or enhanced ionic correlations near the conducting surface, and stabilized by short-range attractive interactions. Continuous adsorption under an applied electric potential offers the possibility of nanoscale films of tailored polymer content realized in a single step.optical waveguide lightmode spectroscopy ͉ poly(L-lysine) ͉ protein adsorption ͉ indium tin oxide I nteractions between charged macromolecules and charged surfaces are ubiquitous in nature (e.g., protein-cell membrane) and are often exploited in technological applications. For example, weakly charged colloidal systems such as paints, inks, and waste water may be stabilized through an adsorbed layer of charged polymer (polyelectrolyte) (1, 2), and polyelectrolyte films containing functional entities (e.g., biomolecules, nanoparticles) may serve as sensors, separation membranes, and electrochemical components (3, 4). Adsorption is usually spontaneous, with electrostatic interactions naturally playing a key role. These interactions, and therefore the adsorption process itself, may be controlled through solution variables such as salt concentration and pH (5-12). However, there generally exists an upper limit to the extent of polyelectrolyte adsorption. The typical situation is for adsorption to be quite rapid (usually at a transport limited rate) and then to saturate, corresponding to the point where interfacial charge accumulation suppresses additional (net) adsorption (1). A clever way to avoid this limit is through the layer-by-layer (LbL) method, where a substrate is alternately exposed to solutions of oppositely charged polyelectrolytes (3, 13). Each exposure results in an increase in adsorbed mass and an overall interfacial charge reversal. The LbL method allows one t...

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Section: Discussionmentioning

confidence: 99%

Continuous polyelectrolyte adsorption under an applied electric potential

Ngankam

Tassel

2007

Proc. Natl. Acad. Sci. U.S.A.

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“…However, improvements are required in many areas, such as prevention of non-specific binding [302][303][304][305][306], sensitivity [307][308][309][310][311][312][313][314][315], site-specific conjugation [316][317][318], bioactivity [319][320][321][322], multiplexing [309,323], and reusability [324][325][326]. Some of these problems can be addressed by using different chemical surface modification approaches.…”

Section: Biosensing-detectionmentioning

confidence: 99%

Peptide-based biopolymers in biomedicine and biotechnology

Chow

Nunalee

Lim

et al. 2008

Materials Science and Engineering: R: Reports

280

231

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Peptides are emerging as a new class of biomaterials due to their unique chemical, physical, and biological properties. The development of peptide-based biomaterials is driven by the convergence of protein engineering and macromolecular self-assembly. This review covers the basic principles, applications, and prospects of peptide-based biomaterials. We focus on both chemically synthesized and genetically encoded peptides, including poly-amino acids, elastin-like polypeptides, silk-like polymers and other biopolymers based on repetitive peptide motifs. Applications of these engineered biomolecules in protein purification, controlled drug delivery, tissue engineering, and biosurface engineering are discussed.

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“…It was found that a fabricated immunosensor based on MHDA-SAM could retain its activity for at least 1 week at 4 °C before its first use. How to regenerate a sensor for continuous use is a challenge for the majority of immunosensors, because the regeneration with extreme pH, temperature and chaotropic agents would decrease the activity significantly (Asanov et al, 1998). There were many methods proposed to settle on the solution to this problem, whose goal was to effectively dissociate most antibody-antigen binding interactions without permanently affecting protein structure, so the regenerated immunosensor could be used to detect the target bacteria again.…”

Section: Stability and Repeatability Of Immunosensormentioning

confidence: 99%

Sensing Escherichia coli O157:H7 via frequency shift through a self-assembled monolayer based QCM immunosensor

Wang

et al. 2008

J. Zhejiang Univ. Sci. B

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By means of the specific immuno-recognition and ultra-sensitive mass detection, a quartz crystal microbalance (QCM) biosensor for Escherichia coli O157:H7 detection was developed in this work. As a suitable surfactant, 16-mercaptohexadecanoic acid (MHDA) was introduced onto the Au surface of QCM, and then self-assembled with N-hydroxysuccinimide (NHS) raster as a reactive intermediate to provide an active interface for the specific antibody immobilization. The binding of target bacteria with the immobilized antibodies decreased the sensor's resonant frequency, and the frequency shift was correlated to the bacterial concentration. The stepwise assembly of the immunosensor was characterized by means of the electrochemical techniques. Using the immersion-dry-immersion procedure, this QCM biosensor could detect 2.0×10 2 colony forming units (CFU)/ml E. coli O157:H7. In order to reduce the fabrication time, a polyelectrolyte layer-by-layer self-assembly (LBL-SA) method was adopted for fast construction. Finally, the reproducibility of this biosensor was discussed.

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Regenerable Biosensor Platform: A Total Internal Reflection Fluorescence Cell with Electrochemical Control

Cited by 141 publications

References 12 publications

Continuous polyelectrolyte adsorption under an applied electric potential

Continuous polyelectrolyte adsorption under an applied electric potential

Peptide-based biopolymers in biomedicine and biotechnology

Sensing Escherichia coli O157:H7 via frequency shift through a self-assembled monolayer based QCM immunosensor

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