scholarly journals An Impedance Sensor in Detection of Immunoglobulin G with Interdigitated Electrodes on Flexible Substrate

2020 ◽  
Vol 10 (11) ◽  
pp. 4012 ◽  
Author(s):  
Kai Jin ◽  
Ping Zhao ◽  
Wenhui Fang ◽  
Yingjiao Zhai ◽  
Siyi Hu ◽  
...  
Keyword(s):  
Gold Electrode ◽  
Electrochemical Impedance ◽  
Flexible Substrate ◽  
Label Free ◽  
Polyethylene Naphthalate ◽  
Early Screening ◽  
Detection Range ◽  
Force Microscopy ◽  
Atomic Force ◽  
Impedance Sensor

Immunoassay plays an important role in the early screening and diagnosis of diseases. The use of electrochemical methods to realize the label-free, specific and rapid detection of antigens has attracted extensive attention from researchers. In this study, we realized the function of immunosensing and detection by lithography, the interdigitated gold electrode on the polyethylene naphthalate (PEN) membrane. Then, the gold electrode was biofunctionalized and the characterization was verified by atomic force microscopy, which was finally for the detection of mice IgG. This immunosensor has a low detection limit, with a broad linear detection range of 0.01–10 ng/mL. The results show that the electrochemical impedance sensor made of metal electrodes based on PEN flexible materials is suitable for immunoassay experiments. If this method could be proved by further studies, broad application prospects can be seen in routine immunoassays.

scholarly journals 3D phonon microscopy with sub-micron axial-resolution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Richard J. Smith ◽  
Fernando Pérez-Cota ◽  
Leonel Marques ◽  
Matt Clark
Keyword(s):  
Signal To Noise Ratio ◽  
Single Cells ◽  
Optical Resolution ◽  
Acquisition Time ◽  
Label Free ◽  
Axial Resolution ◽  
Force Microscopy ◽  
Atomic Force ◽  
Accuracy And Precision ◽  
Good Agreement

AbstractBrillouin light scattering (BLS) is an emerging method for cell imaging and characterisation. It allows elasticity-related contrast, optical resolution and label-free operation. Phonon microscopy detects BLS from laser generated coherent phonon fields to offer an attractive route for imaging since, at GHz frequencies, the phonon wavelength is sub-optical. Using phonon fields to image single cells is challenging as the signal to noise ratio and acquisition time are often poor. However, recent advances in the instrumentation have enabled imaging of fixed and living cells. This work presents the first experimental characterisation of phonon-based axial resolution provided by the response to a sharp edge. The obtained axial resolution is up to 10 times higher than that of the optical system used to take the measurements. Validation of the results are obtained with various polymer objects, which are in good agreement with those obtained using atomic force microscopy. Edge localisation, and hence profilometry, of a phantom boundary is measured with accuracy and precision of approximately 60 nm and 100 nm respectively. Finally, 3D imaging of fixed cells in culture medium is demonstrated.

An electrochemical impedance sensor for the label-free ultrasensitive detection of interleukin-6 antigen

2013 ◽  
Vol 178 ◽  
pp. 310-315 ◽  
Author(s):  
Ting Yang ◽  
Shun Wang ◽  
Huile Jin ◽  
Weiwei Bao ◽  
Shaoming Huang ◽  
...  
Keyword(s):  
Interleukin 6 ◽  
Electrochemical Impedance ◽  
Ultrasensitive Detection ◽  
Label Free ◽  
Impedance Sensor

ELECTROCHEMICAL INVESTIGATION OF 2-THIOHYDANTOIN DERIVATIVES AS CORROSION INHIBITORS FOR MILD STEEL IN ACIDIC MEDIUM

2021 ◽  
Author(s):  
Petar Stanić ◽  
◽  
Nataša Vukićević ◽  
Vesna Cvetković ◽  
Miroslav Pavlović ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mild Steel ◽  
Acidic Medium ◽  
Corrosion Inhibitors ◽  
Electrochemical Impedance ◽  
Electrochemical Investigation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Hcl Solution ◽  
Scanning Electron

Four 2-thiohydantoin derivatives were synthesized and their corrosion inhibition properties on mild steel (MS) in 0.5M HCl solution was evaluated using usual gravimetric and electrochemical methods (weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS). Morphology of the metal surface was characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The study has shown that these compounds provide good protection for mild steel against corrosion in the acidic medium.

scholarly journals Electrodeposition of NiSn-rGO Composite Coatings from Deep Eutectic Solvents and Their Physicochemical Characterization

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1455
Author(s):  
Sabrina Patricia Rosoiu ◽  
Aida Ghiulnare Pantazi ◽  
Aurora Petica ◽  
Anca Cojocaru ◽  
Stefania Costovici ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Choline Chloride ◽  
Physicochemical Characterization ◽  
Metallic Matrix ◽  
Deep Eutectic Solvents ◽  
Force Microscopy ◽  
Atomic Force ◽  
Reduced Graphene

The present work describes, for the first time, the electrodeposition of NiSn alloy/reduced graphene oxide composite coatings (NiSn-rGO) obtained under pulse current electrodeposition conditions from deep eutectic solvents (choline chloride: ethylene glycol eutectic mixtures) containing well-dispersed GO nanosheets. The successful incorporation of the carbon-based material into the metallic matrix has been confirmed by Raman spectroscopy and cross-section scanning electron microscopy (SEM). A decrease in the crystallite size of the coating was evidenced when graphene oxide was added to the electrolyte. Additionally, the topography and the electrical properties of the materials were investigated by atomic force microscopy (AFM). The corrosion behavior in 0.5 M NaCl solution was analyzed through potentiodynamic polarization and electrochemical impedance spectroscopy methods for different immersion periods, up to 336 h, showing a slightly better corrosion performance as compared to pure NiSn alloy.

scholarly journals Mismatch detection in DNA monolayers by atomic force microscopy and electrochemical impedance spectroscopy

2016 ◽  
Vol 7 ◽  
pp. 220-227 ◽  
Author(s):  
Maryse D Nkoua Ngavouka ◽  
Pietro Capaldo ◽  
Elena Ambrosetti ◽  
Giacinto Scoles ◽  
Loredana Casalis ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Electrochemical Impedance ◽  
Complementary Sequence ◽  
Single Base ◽  
Force Microscopy ◽  
Dna Monolayers ◽  
Atomic Force ◽  
The Difference

Background: DNA hybridization is at the basis of most current technologies for genotyping and sequencing, due to the unique properties of DNA base-pairing that guarantee a high grade of selectivity. Nonetheless the presence of single base mismatches or not perfectly matched sequences can affect the response of the devices and the major challenge is, nowadays, to distinguish a mismatch of a single base and, at the same time, unequivocally differentiate devices read-out of fully and partially matching sequences. Results: We present here two platforms based on different sensing strategies, to detect mismatched and/or perfectly matched complementary DNA strands hybridization into ssDNA oligonucleotide monolayers. The first platform exploits atomic force microscopy-based nanolithography to create ssDNA nano-arrays on gold surfaces. AFM topography measurements then monitor the variation of height of the nanostructures upon biorecognition and then follow annealing at different temperatures. This strategy allowed us to clearly detect the presence of mismatches. The second strategy exploits the change in capacitance at the interface between an ssDNA-functionalized gold electrode and the solution due to the hybridization process in a miniaturized electrochemical cell. Through electrochemical impedance spectroscopy measurements on extended ssDNA self-assembled monolayers we followed in real-time the variation of capacitance, being able to distinguish, through the difference in hybridization kinetics, not only the presence of single, double or triple mismatches in the complementary sequence, but also the position of the mismatched base pair with respect to the electrode surface. Conclusion: We demonstrate here two platforms based on different sensing strategies as sensitive and selective tools to discriminate mismatches. Our assays are ready for parallelization and can be used in the detection and quantification of single nucleotide mismatches in microRNAs or in genomic DNA.

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