Impedance Biosensor Incorporating a Carboxylate-Terminated Bidentate Thiol for Antibody Immobilization

Radhakrishnan, Rajeswaran; Pali, Madhavi; Lee, Han Ju; Lee, T. Randall; Suni, Ian Ivar

doi:10.1149/2.0301605jes

Cited by 13 publications

(13 citation statements)

References 45 publications

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“…In both cases, the detection limit for the direct assay (1‐3x10 −4 M) is dramatically reduced by using a sandwich assay (1–5×10 −6 M). Due to such variations between sensor electrodes, impedance biosensors must be calibrated before usage, as recently demonstrated by repeated antibody recycling using 200 mM KSCN as a chaotropic agent .…”

Section: Resultsmentioning

confidence: 99%

Impedance Detection of 3‐Phenoxybenzoic Acid with a Noncompetitive Two‐site Phage Anti‐immunocomplex Assay

et al. 2018

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Both direct and non‐competitive two‐site (sandwich) immunoassays are reported for 3‐phenoxybenzoic acid (3‐PBA) utilizing signal transduction by electrochemical impedance spectroscopy (EIS), and the sandwich immunoassay reduces the detection limit for this small molecule analyte by ∼70×. The direct EIS immunoassay utilizes a polyclonal antibody to 3PBA for biomolecular recognition, while the sandwich EIS immunoassay utilizes in addition a previously reported antiimmunocomplex M13 bacteriophage clone. For both immunoassays, the polyclonal antibody film is immobilized atop an Au electrode by amide bond formation. The direct EIS immunoassay exhibits a 3‐PBA sensitivity of 5.4×104 kΩ cm2 M1, and a detection limit of 2.5×10−4 M (54 μg/ml), while the sandwich EIS immunoassay exhibits a 3PBA sensitivity of 4.2×106 kΩ cm2 M−1, and a detection limit of 3.4×10−6 M (0.74 μg/ml). For the sandwich EIS immunoassay, a constant excess (80×109 PFU/ml) of bacteriophage is maintained during all experiments. This is the first report of a bacteriophage‐assisted sandwich EIS assay.

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Section: Resultsmentioning

confidence: 99%

Impedance Detection of 3‐Phenoxybenzoic Acid with a Noncompetitive Two‐site Phage Anti‐immunocomplex Assay

et al. 2018

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“…Further advancements are envisaged through the application of superior surface modification methods, such as the use of bidendate thiol 16-[3,5-bis(mercaptomethyl)phenoxy]-hexadecanoic acid (BMPHA), the application of proper solutions to stabilize the capture ligands, and the application of AC electrokinetic (ACEK) microfluidics platforms and ACEK microflow mechanisms, such as AC electroosmosis (ACEO) and AC electrothermal (ACET) effects. Furthermore, an increase in the limit of detection may be achieved by combining the biosensor methods with immunoseparation of bacteria from larger volumes [29,30].…”

Section: Discussionmentioning

confidence: 99%

Impedance Sensing Platform for Detection of the Food Pathogen Listeria monocytogenes

et al. 2018

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A great improvement in food safety and quality controls worldwide has been achieved through the development of biosensing platforms. Foodborne pathogens continue to cause serious outbreaks, due to the ingestion of contaminated food. The development of new, sensitive, portable, high-throughput, and automated platforms is a primary objective to allow detection of pathogens and their toxins in foods. Listeria monocytogenes is one common foodborne pathogen. Major outbreaks of listeriosis have been caused by a variety of foods, including milk, soft cheeses, meat, fermented sausages, poultry, seafood and vegetable products. Due to its high sensitivity and easy setup, electrochemical impedance spectroscopy (EIS) has been extensively applied for biosensor fabrication and in particular in the field of microbiology as a mean to detect and quantify foodborne bacteria. Here we describe a miniaturized, portable EIS platform consisting of a microfluidic device with EIS sensors for the detection of L. monocytogenes in milk samples, connected to a portable impedance analyzer for on-field application in clinical and food diagnostics, but also for biosecurity purposes. To achieve this goal microelectrodes were functionalized with antibodies specific for L. monocytogenes. The binding and detection of L. monocytogenes was achieved in the range 2.2 × 103 cfu/mL to 1 × 102 with a Limit of Detection (LoD) of 5.5 cfu/mL.

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Section: Direct Impedance Immunoassay Of 3-pbamentioning

confidence: 99%

“…We recently reported a standard deviation of~16 % across five different antibody-coated sensor electrodes for impe-dance detection of Listeria monocytogenes [31]. This adds complexity for antibody-based biosensors, since calibration requires repeated protein unfolding and refolding, 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 which can be accomplished using a mild chaotropic reagent such as 200 mM KSCN [32,33].…”

Section: Direct Impedance Immunoassay Of 3-pbamentioning

confidence: 99%

Impedance Detection of 3‐Phenoxybenzoic Acid Comparing Wholes Antibodies and Antibody Fragments for Biomolecular Recognition

Pali

Suni

2018

Electroanalysis

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Antibody fragments for detection of 3‐phenoxybenzoic acid (3‐PBA) are created by disulfide bond cleavage with tris(2‐carboxyethyl)phosphine (TCEP). These antibody fragments are employed to improve the sensitivity for 3‐PBA detection by electrochemical impedance spectroscopy (EIS). The sensitivity and detection limit are compared for biomolecular recognition by both polyclonal antibodies and antibody fragments immobilized through amide bond formation atop a self‐assembled monolayer (SAM) on an Au electrode, as well as antibody fragments directly attached to Au through Au−S covalent bond formation. The detection limit for 3‐PBA is dramatically improved (1.1×10−8 M) for direct immobilization of antibody fragments through Au−S covalent bond formation relative to immobilization of either polyclonal antibodies (2.1×10−5 M) or antibody fragments (1.7×10−5 M) through amide bond formation. This can be attributed primarily to the much lower charge transfer resistance (Rct) and higher ionic permeability obtained at biosensor interfaces that do not include an Au‐thiol SAM, allowing easier detection of further changes in Rct. In addition, the exponential dependence of the electron tunnelling rate on biomolecular film thickness increases the sensitivity of the antibody fragments modestly relative to polyclonal antibodies. This is the first quantitative comparison of the use of antibodies and antibody fragments for biomolecular recognition within impedance biosensors.

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Impedance Biosensor Incorporating a Carboxylate-Terminated Bidentate Thiol for Antibody Immobilization

Cited by 13 publications

References 45 publications

Impedance Detection of 3‐Phenoxybenzoic Acid with a Noncompetitive Two‐site Phage Anti‐immunocomplex Assay

Impedance Detection of 3‐Phenoxybenzoic Acid with a Noncompetitive Two‐site Phage Anti‐immunocomplex Assay

Impedance Sensing Platform for Detection of the Food Pathogen Listeria monocytogenes

Impedance Detection of 3‐Phenoxybenzoic Acid Comparing Wholes Antibodies and Antibody Fragments for Biomolecular Recognition

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