scholarly journals Electrical Characterization of Cellulose-Based Membranes towards Pathogen Detection in Water

Biosensors ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 57
Author(s):  
Grégoire Le Brun ◽  
Margo Hauwaert ◽  
Audrey Leprince ◽  
Karine Glinel ◽  
Jacques Mahillon ◽  
...  
Keyword(s):  
Pathogen Detection ◽  
Point Of Care ◽  
Electrical Characterization ◽  
Public Healthcare ◽  
Electrical Detection ◽  
Electrical Measurements ◽  
Experimental Proof ◽  
Bacterial Detection ◽  
Plate Electrode ◽  
Emergency Situations

Paper substrates are promising for development of cost-effective and efficient point-of-care biosensors, essential for public healthcare and environmental diagnostics in emergency situations. Most paper-based biosensors rely on the natural capillarity of paper to perform qualitative or semi-quantitative colorimetric detections. To achieve quantification and better sensitivity, technologies combining paper-based substrates and electrical detection are being developed. In this work, we demonstrate the potential of electrical measurements by means of a simple, parallel-plate electrode setup towards the detection of whole-cell bacteria captured in nitrocellulose (NC) membranes. Unlike current electrical sensors, which are mostly integrated, this plug and play system has reusable electrodes and enables simple and fast bacterial detection through impedance measurements. The characterized NC membrane was subjected to (i) a biofunctionalization, (ii) different saline solutions modelling real water samples, and (iii) bacterial suspensions of different concentrations. Bacterial detection was achieved in low conductivity buffers through both resistive and capacitive changes in the sensed medium. To capture Bacillus thuringiensis, the model microorganism used in this work, the endolysin cell-wall binding domain (CBD) of Deep-Blue, a bacteriophage targeting this bacterium, was integrated into the membranes as a recognition bio-interface. This experimental proof-of-concept illustrates the electrical detection of 107 colony-forming units (CFU) mL−1 bacteria in low-salinity buffers within 5 min, using a very simple setup. This offers perspectives for affordable pathogen sensors that can easily be reconfigured for different bacteria. Water quality testing is a particularly interesting application since it requires frequent testing, especially in emergency situations.

scholarly journals Electrochemical Characterization of Nitrocellulose Membranes towards Bacterial Detection in Water

Proceedings ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 61
Author(s):  
Grégoire Le Brun ◽  
Margo Hauwaert ◽  
Audrey Leprince ◽  
Karine Glinel ◽  
Jacques Mahillon ◽  
...  
Keyword(s):  
Point Of Care ◽  
Colorimetric Detection ◽  
Cost Effective ◽  
Public Healthcare ◽  
Electrical Detection ◽  
Detection Mechanism ◽  
Experimental Proof ◽  
Bacterial Detection ◽  
Cell Wall Binding ◽  
Test Zone

Paper substrates have shown a high potential for development of cost-effective and efficient point-of-care biosensors, essential for public healthcare and environmental diagnostics. Most paper-based biosensors rely on qualitative colorimetric detection schemes with high limits of detection. To overcome this limitation, technologies that combine paper-based substrates and electrochemical detection are being developed to allow for quantification and achieve better performances. In this work, we explore the potential of dielectric measurements towards electrical detection of whole-cell bacteria in nitrocellulose membranes, a paper-derivative. Impedance spectroscopy was considered to characterize the membranes with and without Bacillus thuringiensis cells, used as model microorganism. To specifically target this bacterial strain, phage endolysin cell-wall binding domain (CBD) encoded by a bacteriophage targeting B. thuringiensis were prepared and integrated into the membranes as recognition biointerface. The fluid sample containing the bacteria is conducted in the membrane through passive capillarity, and the bacteria are specifically immobilized in the test zone. Resulting changes of the dielectric properties of the membrane are sensed through impedance changes, highlighting the contribution of ions in the bacterial detection mechanism. This experimental proof-of-concept illustrates the electrical detection of 108 CFU/mL bacteria in low-salinity buffers within 5 min.

In FAB 300mm Wafer Level Atomic Force Probe Characterization

2012 ◽  
Author(s):  
Terence Kane
Keyword(s):  
Electrical Characterization ◽  
Dark Field ◽  
Wafer Level ◽  
Electrical Measurements ◽  
Manufacturing Line ◽  
Atomic Force ◽  
Monitoring Tools ◽  
Voltage Contrast ◽  
The Cost ◽  
Non Destructive

Abstract A 300mm wafer atomic force prober (AFP) has been installed into IBM’s manufacturing line to enable rapid, nondestructive electrical identification of defects. Prior to this tool many of these defects could not detected until weeks or months later. Moving failure analysis to the FAB provides a means of complementing existing FAB inspection and defect review tools as well as providing independent, non-destructive electrical measurements at an early point in the manufacturing cycle [1] Once the wafer sites are non destructively AFP characterized, the wafer is returned to its front opening unified pod (FOUP) carrier and may be reintroduced into the manufacturing line without disruption for further inspection or processing. Whole wafer atomic force probe electrical characterization has been applied to 32nm, 28nm, 20nm and 14nm node technologies. In this paper we explore the cost benefits of performing non-destructive AFP measurements on whole wafers. We have found the methodology of employing a whole wafer AFP tool complements existing in-line manufacturing monitoring tools such as brightfield/dark field optical inspection, SEM in-line inspection and in-line E-beam voltage contrast inspection (EBI).

scholarly journals Label-Free Electrochemical Sensor for Rapid Bacterial Pathogen Detection Using Vancomycin-Modified Highly Branched Polymers

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1872
Author(s):  
Holger Schulze ◽  
Harry Wilson ◽  
Ines Cara ◽  
Steven Carter ◽  
Edward N. Dyson ◽  
...  
Keyword(s):  
Pathogen Detection ◽  
Electrochemical Impedance ◽  
Point Of Care ◽  
Branched Polymers ◽  
Label Free ◽  
Conformation Change ◽  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Staphylococcus Carnosus ◽  
Label Free Detection

Rapid point of care tests for bacterial infection diagnosis are of great importance to reduce the misuse of antibiotics and burden of antimicrobial resistance. Here, we have successfully combined a new class of non-biological binder molecules with electrochemical impedance spectroscopy (EIS)-based sensor detection for direct, label-free detection of Gram-positive bacteria making use of the specific coil-to-globule conformation change of the vancomycin-modified highly branched polymers immobilized on the surface of gold screen-printed electrodes upon binding to Gram-positive bacteria. Staphylococcus carnosus was detected after just 20 min incubation of the sample solution with the polymer-functionalized electrodes. The polymer conformation change was quantified with two simple 1 min EIS tests before and after incubation with the sample. Tests revealed a concentration dependent signal change within an OD600 range of Staphylococcus carnosus from 0.002 to 0.1 and a clear discrimination between Gram-positive Staphylococcus carnosus and Gram-negative Escherichia coli bacteria. This exhibits a clear advancement in terms of simplified test complexity compared to existing bacteria detection tests. In addition, the polymer-functionalized electrodes showed good storage and operational stability.

scholarly journals Study of the Molecule Adsorption Process during the Molecular Doping

Nanomaterials ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1899
Author(s):  
Mattia Pizzone ◽  
Maria Grazia Grimaldi ◽  
Antonino La La Magna ◽  
Neda Rahmani ◽  
Silvia Scalese ◽  
...  
Keyword(s):  
Density Functional ◽  
Electrical Characterization ◽  
Molecular Surface ◽  
Doping Profile ◽  
Electrical Measurements ◽  
Self Assembled Monolayer ◽  
Depth Study ◽  
Molecular Doping ◽  
Dopant Atoms ◽  
Molecular Layers

Molecular Doping (MD) involves the deposition of molecules, containing the dopant atoms and dissolved in liquid solutions, over the surface of a semiconductor before the drive-in step. The control on the characteristics of the final doped samples resides on the in-depth study of the molecule behaviour once deposited. It is already known that the molecules form a self-assembled monolayer over the surface of the sample, but little is known about the role and behaviour of possible multiple layers that could be deposited on it after extended deposition times. In this work, we investigate the molecular surface coverage over time of diethyl-propyl phosphonate on silicon, by employing high-resolution morphological and electrical characterization, and examine the effects of the post-deposition surface treatments on it. We present these data together with density functional theory simulations of the molecules–substrate system and electrical measurements of the doped samples. The results allow us to recognise a difference in the bonding types involved in the formation of the molecular layers and how these influence the final doping profile of the samples. This will improve the control on the electrical properties of MD-based devices, allowing for a finer tuning of their performance.

scholarly journals Recent Developments towards Portable Point-of-Care Diagnostic Devices for Pathogen Detection

2022 ◽  
Author(s):  
Sharmili Roy ◽  
FAREEHA ARSHAD ◽  
Shimaa Eissa ◽  
Mohammadali Safavieh ◽  
Sanaa G. Alattas ◽  
...  
Keyword(s):  
Global Health ◽  
Infectious Diseases ◽  
Pathogen Detection ◽  
Point Of Care ◽  
Rapid Development ◽  
Diagnostic Tools ◽  
Recent Developments

The rapid development of accurate and quick diagnostic tools for infectious diseases has made a massive impact in global health. POC devices for pathogen detection have primarily contributed to clinical...

Surface Functionalization of SiC for Biosensor Applications

2007 ◽  
Vol 556-557 ◽  
pp. 957-960 ◽  
Author(s):  
R.M. Petoral Jr. ◽  
Gholam Reza Yazdi ◽  
C. Vahlberg ◽  
Mikael Syväjärvi ◽  
Anita Lloyd Spetz ◽  
...  
Keyword(s):  
Contact Angle ◽  
Surface Functionalization ◽  
Electrical Characterization ◽  
Silanol Group ◽  
Thiol Group ◽  
Native Oxide ◽  
Electrical Measurements ◽  
Anchoring Group ◽  
Face Side ◽  
Biosensor Applications

SiC is a biocompatible material and a candidate as a transducer for biosensors. Here we have investigated the possibility to functionalize SiC with biomolecules. We have also processed very simple devices and performed electrical characterization. Double polished SiC samples with a C-face substrate and Si-face low doped epilayer have been functionalized on both sides. The SiC was first treated by HF in order to remove the native oxide, partly successful on the Si-face side but probably not on the C-face side. MPTMS, 3-mercaptopropyl trimethoxysilane, was chosen as the biomolecule since it has both a silanol group to be used as an anchoring group to the substrate and a thiol group available for further linking possibilities. The functionalization was evaluated by XPS, contact angle experiments, AFM and electrical measurements. The MPTMS molecules attached with the thiol (or sulphur containing) group pointing out from the surface on both faces of the SiC. Interesting differences between the two faces are however revealed by the analysis.

scholarly journals Quantitative Point-of-Care Pathogen Detection in Septicemia

2008 ◽  
Vol 7 (3) ◽  
pp. 107-110 ◽  
Author(s):  
Nam K. Tran ◽  
David Wisner ◽  
Timothy Albertson ◽  
Stuart Cohen ◽  
David Greenhalgh ◽  
...  
Keyword(s):  
Pathogen Detection ◽  
Point Of Care

scholarly journals Individualization and Electrical Characterization of SiGe Nanowires

2012 ◽  
Vol 1408 ◽  
Author(s):  
M. Monasterio ◽  
A. Rodríguez ◽  
T. Rodríguez ◽  
C. Ballesteros
Keyword(s):  
Electrical Characterization ◽  
Ex Situ ◽  
Electrical Measurements ◽  
Measured Resistance ◽  
Single Nanowires ◽  
Very High

ABSTRACTSiGe nanowires of different Ge atomic fractions up to 15% were grown and ex-situ n-type doped by diffusion from a solid source in contact with the sample. The phenomenon of dielectrophoresis was used to locate single nanowires between pairs of electrodes in order to carry out electrical measurements. The measured resistance of the as-grown nanowires is very high, but it decreases more than three orders of magnitude upon doping, indicating that the doping procedure used has been effective.

scholarly journals Very High Sustainable Forward Current Densities on 4H-SiC p-n Junctions Formed by VLS Localized Epitaxy of Heavily Al-Doped p++ Emitters

2017 ◽  
Vol 897 ◽  
pp. 63-66
Author(s):  
Selsabil Sejil ◽  
Loic Lalouat ◽  
Mihai Lazar ◽  
Davy Carole ◽  
Christian Brylinski ◽  
...  
Keyword(s):  
Electrical Characterization ◽  
Electrical Measurements ◽  
Pin Diodes ◽  
Low Leakage ◽  
Forward Current ◽  
Low Leakage Current ◽  
Current Densities ◽  
P Type ◽  
Electrical Characterizations ◽  
Very High

This study deals with the electrical characterization of PiN diodes fabricated on a 4°off-axis 4H-SiC n+ substrate with a n- epilayer (1×1016 cm-3 / 10 µm). Optimized p++ epitaxial areas were grown by Vapour-Liquid-Solid (VLS) transport to form p+ emitters localized in etched wells with 1 µm depth. Incorporated Al level in the VLS p++ zones was checked by SIMS (Secondary Ion Mass Spectroscopy), and the doping level was found in the range of 1-3×1020 at.cm-3. Electrical characterizations were performed on these PiN diodes, with 800 nm deposit of aluminium as ohmic contact on p-type SiC. Electrical measurements show a bipolar behaviour, and very high sustainable forward current densities ≥ 3 kA.cm-2, preserving a low leakage current density in reverse bias. These measurements were obtained on structures without any passivation and no edge termination.

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