Self-assembled PEG monolayer based SPR immunosensor for label-free detection of insulin

2007 ◽  
Vol 22 (7) ◽  
pp. 1382-1389 ◽  
Author(s):  
K. Vengatajalabathy Gobi ◽  
Hiroyuki Iwasaka ◽  
Norio Miura
Keyword(s):  
Label Free ◽  
Spr Immunosensor ◽  
Label Free Detection ◽  
Self Assembled

scholarly journals Microfluidic Impedance Biosensor Chips Using Sensing Layers Based on DNA-Based Self-Assembled Monolayers for Label-Free Detection of Proteins

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 80
Author(s):  
Khaled Alsabbagh ◽  
Tim Hornung ◽  
Achim Voigt ◽  
Sahba Sadir ◽  
Taleieh Rajabi ◽  
...  
Keyword(s):  
Troponin I ◽  
Electrochemical Impedance ◽  
Specific Binding ◽  
Self Assembled Monolayers ◽  
Significant Shift ◽  
Label Free ◽  
Label Free Detection ◽  
Assembled Monolayers ◽  
Self Assembled ◽  
Biosensor Chip

A microfluidic chip for electrochemical impedance spectroscopy (EIS) is presented as bio-sensor for label-free detection of proteins by using the example of cardiac troponin I. Troponin I is one of the most specific diagnostic serum biomarkers for myocardial infarction. The microfluidic impedance biosensor chip presented here consists of a microscope glass slide serving as base plate, sputtered electrodes, and a polydimethylsiloxane (PDMS) microchannel. Electrode functionalization protocols were developed considering a possible charge transfer through the sensing layer, in addition to analyte-specific binding by corresponding antibodies and reduction of nonspecific protein adsorption to prevent false-positive signals. Reagents tested for self-assembled monolayers (SAMs) on gold electrodes included thiolated hydrocarbons and thiolated oligonucleotides, where SAMs based on the latter showed a better performance. The corresponding antibody was covalently coupled on the SAM using carbodiimide chemistry. Sampling and measurement took only a few minutes. Application of a human serum albumin (HSA) sample, 1000 ng/mL, led to negligible impedance changes, while application of a troponin I sample, 1 ng/mL, led to a significant shift in the Nyquist plot. The results are promising regarding specific detection of clinically relevant concentrations of biomarkers, such as cardiac markers, with the newly developed microfluidic impedance biosensor chip.

Blue-Emitting Self-Assembled Polymer Electrolytes for Fast, Sensitive, Label-Free Detection of Cu(II) Ions in Aqueous Media

ACS Nano ◽  
2013 ◽  
Vol 7 (7) ◽  
pp. 6162-6169 ◽  
Author(s):  
Hyungmin Ahn ◽  
Sung Yeon Kim ◽  
Onnuri Kim ◽  
Ilyoung Choi ◽  
Chang-Hoon Lee ◽  
...  
Keyword(s):  
Polymer Electrolytes ◽  
Aqueous Media ◽  
Label Free ◽  
Label Free Detection ◽  
Self Assembled

scholarly journals Surface plasmon resonance immunosensor for label-free detection of BIRC5 biomarker in spontaneously occurring canine mammary tumours

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Subas Chandra Jena ◽  
Sameer Shrivastava ◽  
Sonal Saxena ◽  
Naveen Kumar ◽  
Swapan Kumar Maiti ◽  
...  
Keyword(s):  
Surface Plasmon Resonance ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Clinical Samples ◽  
Label Free ◽  
Calibration Experiment ◽  
Spr Immunosensor ◽  
Label Free Detection ◽  
Diagnostic Applications ◽  
Equilibrium Dissociation

Abstract We report detection of Baculoviral inhibitor of apoptosis repeat containing-5 (BIRC5) protein biomarker in dog serum by label-free surface plasmon resonance (SPR) immunosensor. Initially, overexpression of BIRC5 in canine mammary tumour (CMT) tissues was confirmed by real-time PCR. Recombinant BIRC5 was produced and protein specific antibodies developed in guinea pig specifically reacted with native protein in immunohistochemistry and immunocytochemistry. SPR immunosensor was developed by fabricating anti-BIRC5 antibodies on gold sensor disc. The equilibrium dissociation constant, (KD = kd/ka) was 12.1 × 10−12 M; which indicates that antibodies are of high affinity with sensitivity in picomolar range. The SPR assay could detect as low as 6.25 pg/ml of BIRC5 protein in a calibration experiment (r2 = 0.9964). On testing real clinical samples, 95% specificity and 73.33% sensitivity were recorded. The average amount of serum BIRC5 in dogs with CMT was 110.02 ± 9.77 pg/ml; whereas, in non-cancerous disease conditions, 44.79 ± 4.28 pg/ml and in healthy dog sera 30.28 ± 2.99 pg/ml protein was detected. The SPR immunosensor for detection of BIRC5 in dog sera is reported for the first time and this may find prognostic and diagnostic applications in management of CMT. In future, ‘on-site’ sensors can be developed using this technique for near-patient testing.

Electrochemical Aptasensor for Label-Free Detection of Protein Based on Gold Nanoparticle Involved Self-Assembly

2013 ◽  
Vol 310 ◽  
pp. 177-182
Author(s):  
Song Bai Zhang ◽  
Bing Jun Zhang ◽  
Qian Liu ◽  
Xia Hu ◽  
Li Ying Zheng ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Self Assembly ◽  
Gold Electrode ◽  
Hot Water ◽  
Target Protein ◽  
Capture Probe ◽  
Label Free ◽  
Label Free Detection ◽  
Self Assembled

A label-free electrochemical biosensing strategy based on gold nanoparticle involved layer-by-layer self assembly for the detection of protein is proposed using platelet derived growth factor-BB dimer (PDGF-BB) as the model analyte. Utilizing the strong sulfur-Au affinity, ethanthiol and capture probe modified gold nanoparticles are self-assembled onto the surface of gold electrode successively. The aptamer probe for target protein hybridizes with the capture probe and the biosensor is fabricated. By measuring ac current voltammetry, the target protein can be sensitively detected in a linear dynamic range from 1-1000 ng/mL with a low detection limit of 0.5 ng/mL. Making use of self-assembled gold nanoparticles layer, a large amount of capture probes can be modified onto the gold electrode, supporting the high sensitivity of the proposed strategy. In addition, good reproducibility, high selectivity and stability are achieved. In particular, the biosensor can be easily regenerated by melting in hot water, making it reusable.

scholarly journals An Electrochemical Immunosensor Based on a Self-Assembled Monolayer Modified Electrode for Label-Free Detection of α-Synuclein

Sensors ◽  
2020 ◽  
Vol 20 (3) ◽  
pp. 617 ◽  
Author(s):  
Chuang-Ye Ge ◽  
Md. Mahbubur Rahman ◽  
Wei Zhang ◽  
Nasrin Siraj Lopa ◽  
Lei Jin ◽  
...  
Keyword(s):  
Dynamic Range ◽  
Electrochemical Impedance ◽  
Charge Transfer Resistance ◽  
Label Free ◽  
Serum Samples ◽  
Self Assembled Monolayer ◽  
Electrochemical Impedance Spectra ◽  
Transfer Resistance ◽  
Label Free Detection ◽  
Self Assembled

This research demonstrated the development of a simple, cost-effective, and label-free immunosensor for the detection of α-synuclein (α-Syn) based on a cystamine (CYS) self-assembled monolayer (SAM) decorated fluorine-doped tin oxide (FTO) electrode. CYS-SAM was formed onto the FTO electrode by the adsorption of CYS molecules through the head sulfur groups. The free amine (–NH2) groups at the tail of the CYS-SAM enabled the immobilization of anti-α-Syn-antibody, which concurrently allowed the formation of immunocomplex by covalent bonding with α-Syn-antigen. The variation of the concentrations of the attached α-Syn at the immunosensor probe induced the alternation of the current and the charge transfer resistance (Rct) for the redox response of [Fe(CN)6]3−/4−, which displayed a linear dynamic range from 10 to 1000 ng/mL with a low detection limit (S/N = 3) of ca. 3.62 and 1.13 ng/mL in differential pulse voltammetry (DPV) and electrochemical impedance spectra (EIS) measurements, respectively. The immunosensor displayed good reproducibility, anti-interference ability, and good recoveries of α-Syn detection in diluted human serum samples. The proposed immunosensor is a promising platform to detect α-Syn for the early diagnose of Parkinson’s disease, which can be extended for the determination of other biologically important biomarkers.

A label-free electrochemical immunosensor for beta-amyloid detection

2016 ◽  
Vol 8 (31) ◽  
pp. 6115-6120 ◽  
Author(s):  
Ajeet Kaushik ◽  
Pratikkumar Shah ◽  
Phani Kiran Vabbina ◽  
Rahul Dev Jayant ◽  
Sneham Tiwari ◽  
...  
Keyword(s):  
Beta Amyloid ◽  
Electrochemical Immunosensor ◽  
Label Free ◽  
Self Assembled Monolayer ◽  
Interdigitated Electrode ◽  
Label Free Detection ◽  
Self Assembled

A label-free detection of beta-amyloid (βA) proteins using an electrochemical immunosensor fabricated via immobilizing specific anti-beta-amyloid antibodies (An-βA-Abs) onto an interdigitated electrode of gold (IDE-Au) modified using a self-assembled monolayer (SAM) of dithiobis(succinimidyl propionate) [DTSP] is presented here.

scholarly journals Microfluidic Impedance Biosensor Chip with DNA-Based Self-Assembled Monolayers for Label-Free Detection of Cardiac Biomarker Troponin I

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 38
Author(s):  
Khaled Alsabbagh ◽  
Tim Hornung ◽  
Achim Voigt ◽  
Sahba Sadir ◽  
Taleieh Rajabi ◽  
...  
Keyword(s):  
Troponin I ◽  
Electrochemical Impedance ◽  
Glass Slide ◽  
Self Assembled Monolayers ◽  
Label Free ◽  
Label Free Detection ◽  
Assembled Monolayers ◽  
Pdms Microchannel ◽  
Self Assembled ◽  
Biosensor Chip

A microfluidic chip for electrochemical impedance spectroscopy (EIS) is presented as biosensor for the detection of cardiac troponin I (cTnI). Troponin I is one of the most specific diagnostic serum biomarkers for myocardial infarction. As impedimetric biosensors allow direct and label-free analyte detection, they are particularly suitable for fast biomarker detection. This is essential in the diagnosis of cardiac infarctions to enable an early treatment promoting a positive outcome. The microfluidic impedance biosensor chip presented here consists of a microscope glass slide serving as base plate, sputtered electrodes, and a polydimethylsiloxane (PDMS) microchannel. Electrode functionalization protocols were developed considering a low initial impedance in addition to analyte-specific binding by corresponding antibodies and reduction of non-specific protein adsorption to prevent false-positive signals. Reagents tested for self-assembled monolayers (SAMs) on gold electrodes included thiolated hydrocarbons and thiolated oligonucleotides, where SAMs based on the latter showed a better performance. The corresponding antibody (anti-cTnI) was covalently coupled on the SAM using carbodiimide chemistry. The PDMS microchannel was bonded on the glass slide with the functionalized electrodes, and the completed microfluidic impedance biosensor chip was connected to the readout system. Sampling and measurement took only a few minutes. Application of a human serum albumin (HSA) sample, 1000 ng/mL, led to negligible signal changes, while application of a troponin I sample, 1 ng/mL, led to a significant signal shift in the Nyquist plot. The results are promising regarding specific detection of clinically relevant concentrations of cardiac markers with the newly developed impedance biosensor chip.

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