scholarly journals Development of Electrochemical Aptasensor for Lung Cancer Diagnostics in Human Blood

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7851
Author(s):  
Anastasiia V. Shabalina ◽  
Darya O. Sharko ◽  
Yury E. Glazyrin ◽  
Elena A. Bolshevich ◽  
Oksana V. Dubinina ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Human Blood ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Layer Structure ◽  
Cancer Diagnostics ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Cyclic Voltammogram ◽  
Electrochemical Aptasensor

We describe the preparation and characterization of an aptamer-based electrochemical sensor to lung cancer tumor markers in human blood. The highly reproducible aptamer sensing layer with a high density (up to 70% coverage) on the gold electrode was made. Electrochemical methods and confocal laser scanning microscopy were used to study the stability of the aptamer layer structure and binding ability. A new blocking agent, a thiolated oligonucleotide with an unrelated sequence, was applied to fill the aptamer layer’s defects. Electrochemical aptasensor signal processing was enhanced using deep learning and computer simulation of the experimental data array. It was found that the combinations (coupled and tripled) of cyclic voltammogram features allowed for distinguishing between the samples from lung cancer patients and healthy candidates with a mean accuracy of 0.73. The capacitive component from the non-Faradic electrochemical impedance spectroscopy data indicated the tumor marker’s presence in a sample. These findings allowed for the creation of highly informative aptasensors for early lung cancer diagnostics.

Influence of the Electrolyte Composition on the Corrosion Behavior of Anodized AZ31B Magnesium Alloy

2020 ◽  
Vol 1012 ◽  
pp. 424-429
Author(s):  
Leandro Antonio de Oliveira ◽  
Renato Altobelli Antunes
Keyword(s):  
Magnesium Alloy ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Electrolyte Composition ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Mixed Solution ◽  
Protective Properties ◽  
Az31b Magnesium Alloy ◽  
Substrate Dissolution

Investigations have been performed to study the effects of the electrolyte composition on the properties of anodized films grown on AZ31B magnesium alloy. The corrosion protection ability of the oxide layers was explored by using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy. Film morphology was examined by scanning electron microscopy and confocal laser scanning microscopy. In spite of its higher roughness average, the film formed in the silicate and hydroxide mixed solution enhanced the protective properties of the anodized layer, thus reducing the substrate dissolution rate.

Characterisation of electrochemical immunosensor for detection of viable not-culturable forms of Legionellla pneumophila in water samples

2015 ◽  
Vol 69 (11) ◽  
Author(s):  
Dejla Sboui ◽  
Mina Souiri ◽  
Stephanie Reynaud ◽  
Sabine Palle ◽  
Manel Ben Ismail ◽  
...  
Keyword(s):  
Legionella Pneumophila ◽  
Indium Tin Oxide ◽  
Membrane Filtration ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Angle Measurement ◽  
Electrochemical Immunosensor ◽  
Laser Scanning Microscopy ◽  
Confocal Laser

AbstractLegionella pneumophila may cause a fatal pneumonia in humans known as Legionnaires’ disease (LD). The strategies of L. pneumophila to adapt to and resist stressful environmental conditions include the ability to enter into a VBNC (viable but not culturable) state. The detection of L. pneumophila in environmental samples benefits from the use of standardised methods: for detection and enumeration following membrane filtration (AFNOR T90-431, ISO 11731) and detection and quantification by polymerase chain reaction PCR (AFNOR T90-471, ISO 12869). Culture is hampered by its inability to detect VBNC forms and PCR is unable to discriminate between live and dead bacteria. The present immunosensor was obtained by the immobilisation of a monoclonal anti-L. pneumophila antibody (MAb) on an indium-tin oxide (ITO) electrode by the self-assembled monolayers (SAMs) method using an aminosilane. The immunosensor was characterised by wettability (contact angle measurement), atomic force microscopy (AFM), confocal laser scanning microscopy (CLSM), and electrochemical impedance spectroscopy (EIS). A limit of detection of 10 bacteria per mL was observed on artificial samples.

Finding the comfort zone: Online-monitoring of electroactive bacteria colonising electrode surfaces with different chemical properties

2020 ◽  
Author(s):  
Hanna Frühauf ◽  
Markus Stöckl ◽  
Dirk Holtmann
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Confocal Laser Scanning Microscopy ◽  
Electrode Surface ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Flow Cell ◽  
Laser Scanning Microscopy ◽  
Confocal Laser

<p>Mechanisms of electron transfer vary greatly within the diverse group of electroactive microorganisms and so does the need to attach to the electrode surface, e.g. by forming a biofilm.</p> <p>Electrochemical impedance spectroscopy (EIS) and confocal laser scanning microscopy (CLSM) are well established methods to monitor cell attachment to an electrode surface and have therefore been combined in a flow cell as a screening system. The flow cell, equipped with a transparent indium tin oxide working electrode (ITO WE), allows monitoring of attachment processes in real time with minimal needs for additional biofilm preparation. In preliminary experiments the flow cell was successfully used as microbial fuel cell (MFC) with a potential of +0.4 V vs. Ag/AgCl using <em>Shewanella oneidensis</em> as electroactive model organism. [1]</p> <p>Commonly, graphite-based electrode materials are used in bioelectrochemical systems due to their low costs and high conductivity. However, the hydrophobic and negatively charged surface is not yet optimal for microbial attachment. There are numerous attempts on electrode surface engineering in order to overcome this problem. In the majority of studies the biofilm analysis and evaluation of the attachment takes place at the end of the experiment, neglecting the impacts of the chemical surface properties and initial electrode conditioning during the very beginning of biofilm formation.</p> <p>To investigate initial attachment and biofilm formation in real-time, the transparent ITO-electrode is coated with polyelectrolytes differing in hydrophobicity and polarity to evaluate their effects on the initial surface colonisation by different electroactive microorganisms. Combining CLSM and EIS, both, surface coverage and electrochemical interaction of electrode-associated bacteria can be assessed.</p> <p>With this we aim to understand and ease initial steps of biofilm formation to improve efficiency of bioelectrochemical applications, e.g. with regards to start-up time.</p> <p> </p> <p>[1] Stöckl, M., Schlegel, C., Sydow, A., Holtmann, D., Ulber, R., & Mangold, K. M. (2016). Membrane separated flow cell for parallelized electrochemical impedance spectroscopy and confocal laser scanning microscopy to characterize electro-active microorganisms. <em>Electrochimica Acta</em>, 220, 444-452.</p>

scholarly journals Electrochemical and surface analytical techniques applied to microbiologically influenced corrosion investigation

2018 ◽  
Vol 36 (4) ◽  
pp. 349-363 ◽  
Author(s):  
László Trif ◽  
Abdul Shaban ◽  
Judit Telegdi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Electrochemical Techniques ◽  
Analytical Techniques ◽  
Laser Scanning Microscopy ◽  
Microbiologically Influenced Corrosion ◽  
Microbial Consortia ◽  
Confocal Laser ◽  
The Impact

AbstractSuitable application of techniques for detection and monitoring of microbiologically influenced corrosion (MIC) is crucial for understanding the mechanisms of the interactions and for selecting inhibition and control approaches. This paper presents a review of the application of electrochemical and surface analytical techniques in studying the MIC process of metals and their alloys. Conventional electrochemical techniques, such as corrosion potential (Ecorr), redox potential, dual-cell technique, polarization curves, electrochemical impedance spectroscopy (EIS), electrochemical noise (EN) analysis, and microelectrode techniques, are discussed, with examples of their use in various MIC studies. Electrochemical quartz crystal microbalance, which is newly used in MIC study, is also discussed. Microscopic techniques [scanning electron microscopy (SEM), environmental SEM (ESEM), atomic force microscopy (AFM), confocal laser microscopy (CLM), confocal laser scanning microscopy (CLSM), confocal Raman microscopy] and spectroscopic analytical methods [Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS)] are also highlighted. This review highlights the heterogeneous characteristics of microbial consortia and use of special techniques to study their probable effects on the metal substrata. The aim of this review is to motivate using a combination of new procedures for research and practical measurement and calculation of the impact of MIC and biofilms on metals and their alloys.

scholarly journals Antimicrobial and Anticorrosion Activity of a Novel Composite Biocide against Mixed Bacterial Strains in Taiwanese Marine Environments

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6156
Author(s):  
Soul-Yi Chang ◽  
Shih-Yen Huang ◽  
Yu-Ren Chu ◽  
Shun-Yi Jian ◽  
Kai-Yin Lo ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Laser Scanning Microscopy ◽  
304 Stainless Steel ◽  
Single Type ◽  
Confocal Laser ◽  
Subtropical Climate ◽  
Marine Environments ◽  
Bacterial Strains

Taiwan is an island with a humid subtropical climate. The relatively warm seawater results in biofouling of the surfaces of marine facilities. Biocide application is a common practice for combating and eliminating adhesive fouling. However, a single type of biocide may have limited antimicrobial effects due to the relatively high microbial diversity in marine environments. Therefore, applying a mixture of various biocides may be necessary. In this study, the antimicrobial and anticorrosion properties of a newly designed composite biocide, namely a combination of thymol and benzyldimethyldodecylammonium chloride, were investigated by applying the biocide to 304 stainless steel substrates immersed in inocula containing bacterial strains from Tamsui and Zuoying harbors. The ability of 3TB and 5TB treatments to prevent sessile cells and biofilm formation on the 304 stainless steel coupon surface was determined through scanning electron microscopy investigation. In addition, confocal laser scanning microscopy indicated that the 5TB treatment achieved a greater bactericidal effect in both the Tamsui and Zuoying inocula. Moreover, electrochemical impedance spectroscopy revealed that the diameter of the Nyquist semicircle was almost completely unaffected by Tamsui or Zuoying under the 5TB treatment. Through these assessments of antimicrobial activity and corrosion resistance, 5TB treatment was demonstrated to have superior bactericidal activity against mixed strains in both southern and northern Taiwanese marine environments.

scholarly journals Study of the Corrosion Process of AZ91D Magnesium Alloy during the First Hours of Immersion in 3.5 wt.% NaCl Solution

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Vanessa Mandarano Pinela ◽  
Leandro Antônio de Oliveira ◽  
Mara Cristina Lopes de Oliveira ◽  
Renato Altobelli Antunes
Keyword(s):  
Magnesium Alloy ◽  
Photoelectron Spectroscopy ◽  
Laser Scanning ◽  
Electrochemical Impedance ◽  
Corrosion Process ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Nacl Solution ◽  
X Ray ◽  
Az91d Magnesium Alloy

The AZ91D magnesium alloy was immersed in 3.5 wt.% NaCl solution at room temperature for times ranging from 1 minute up to 72 hours. The aim was to investigate the evolution of the corrosion process using confocal laser scanning microscopy (CLSM), electrochemical impedance spectroscopy, and X-ray photoelectron spectroscopy. The microstructure of the as-received alloy was initially characterized by optical microscopy and scanning electron microscopy (SEM). The crystalline phases were identified by X-ray diffractometry. The main phases were primary-α, eutectic-α, and β (Mg17Al12). Vickers microhardness markings were made on the surface of one etched sample to facilitate the identification of the same region at each different immersion time, thus enabling the observation of the corrosion process evolution. Corrosion initiates at the grain boundaries of the eutectic microconstituent and, then, propagates through primary α-grains. The β-phase was less severely attacked.

scholarly journals Improvement of Pulmonary Photodynamic Therapy: Nebulisation of Curcumin-Loaded Tetraether Liposomes

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1243
Author(s):  
Jennifer Lehmann ◽  
Michael R. Agel ◽  
Konrad H. Engelhardt ◽  
Shashank R. Pinnapireddy ◽  
Sabine Agel ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Photodynamic Therapy ◽  
Laser Scanning ◽  
Laser Doppler Anemometry ◽  
Morphological Characteristics ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Air Jet ◽  
Aerodynamic Properties

Lung cancer is one of the most common causes for a high number of cancer related mortalities worldwide. Therefore, it is important to improve the therapy by finding new targets and developing convenient therapies. One of these novel non-invasive strategies is the combination of pulmonary delivered tetraether liposomes and photodynamic therapy. In this study, liposomal model formulations containing the photosensitiser curcumin were nebulised via two different technologies, vibrating-mesh nebulisation and air-jet nebulisation, and compared with each other. Particle size and ζ-potential of the liposomes were investigated using dynamic light scattering and laser Doppler anemometry, respectively. Furthermore, atomic force microscopy and transmission electron microscopy were used to determine the morphological characteristics. Using a twin glass impinger, suitable aerodynamic properties were observed, with the fine particle fraction of the aerosols being ≤62.7 ± 1.6%. In vitro irradiation experiments on lung carcinoma cells (A549) revealed an excellent cytotoxic response of the nebulised liposomes in which the stabilisation of the lipid bilayer was the determining factor. Internalisation of nebulised curcumin-loaded liposomes was visualised utilising confocal laser scanning microscopy. Based on these results, the pulmonary application of curcumin-loaded tetraether liposomes can be considered as a promising approach for the photodynamic therapy against lung cancer.

scholarly journals Gold Rod-Polyethylene Glycol-Carbon Dot Nanohybrids as Phototheranostic Probes

Nanomaterials ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 706 ◽  
Author(s):  
Yuefang Niu ◽  
Guo Ling ◽  
Li Wang ◽  
Shanyue Guan ◽  
Zheng Xie ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Carbon Dots ◽  
Laser Scanning ◽  
Cancer Diagnostics ◽  
Laser Scanning Microscopy ◽  
In Vitro Assays ◽  
Confocal Laser ◽  
Fluorescence Lifetime Imaging ◽  
Imaging Performance

Emphasis using phototheranostics has been placed on the construction of multifunctional nanoplatforms for simultaneous tumor diagnosis and therapy. Herein, we put forth a novel nanosized luminescent material using the incorporation of red emissive carbon dots on gold nanorods through polyethylene glycol as a covalent linkage for dual-modal imaging and photothermal therapy. The novel nanohybrids, not only retain the optical properties of the gold nanorod and carbon dots, but also possess superior imaging performance in both confocal laser scanning microscopy and fluorescence lifetime imaging microscopy. The nanohybrids also exhibit excellent photothermal performance as phototheranostic nanohybrid probes for in vitro assays. This study promises a new multifunctional nanoplatform for cancer diagnostics and therapeutics.

3-D imaging of cells using a confocal laser scanning microscope and digital image processing

1988 ◽  
Vol 46 ◽  
pp. 96-97
Author(s):  
Thomas M. Jovin ◽  
Michel Robert-Nicoud ◽  
Donna J. Arndt-Jovin ◽  
Thorsten Schormann
Keyword(s):  
Laser Scanning ◽  
Confocal Laser Scanning Microscope ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Confocal Laser ◽  
Scanning Microscope ◽  
Laser Scanning Microscope ◽  
Biochemical Processes ◽  
Adjacent Structures

Light microscopic techniques for visualizing biomolecules and biochemical processes in situ have become indispensable in studies concerning the structural organization of supramolecular assemblies in cells and of processes during the cell cycle, transformation, differentiation, and development. Confocal laser scanning microscopy offers a number of advantages for the in situ localization and quantitation of fluorescence labeled targets and probes: (i) rejection of interfering signals emanating from out-of-focus and adjacent structures, allowing the “optical sectioning” of the specimen and 3-D reconstruction without time consuming deconvolution; (ii) increased spatial resolution; (iii) electronic control of contrast and magnification; (iv) simultanous imaging of the specimen by optical phenomena based on incident, scattered, emitted, and transmitted light; and (v) simultanous use of different fluorescent probes and types of detectors.We currently use a confocal laser scanning microscope CLSM (Zeiss, Oberkochen) equipped with 3-laser excitation (u.v - visible) and confocal optics in the fluorescence mode, as well as a computer-controlled X-Y-Z scanning stage with 0.1 μ resolution.

Sign in / Sign up

Export Citation Format

Share Document