scholarly journals Doped Polythiophene Chiral Electrodes as Electrochemical Biosensors

Electrochem ◽  
2021 ◽  
Vol 2 (4) ◽  
pp. 677-688
Author(s):  
M’hamed Chahma
Keyword(s):  
Electronic Properties ◽  
Alternative Pathway ◽  
Electrochemical Stability ◽  
Electrochemical Biosensors ◽  
Surface Immobilization ◽  
Electrode Surfaces ◽  
Conducting Materials ◽  
Wide Range

π-conducting materials such as chiral polythiophenes exhibit excellent electrochemical stability in doped and undoped states on electrode surfaces (chiral electrodes), which help tune their physical and electronic properties for a wide range of uses. To overcome the limitations of traditional surface immobilization methods, an alternative pathway for the detection of organic and bioorganic targets using chiral electrodes has been developed. Moreover, chiral electrodes have the ability to carry functionalities, which helps the immobilization and recognition of bioorganic molecules. In this review, we describe the use of polythiophenes for the design of chiral electrodes and their applications as electrochemical biosensors.

scholarly journals Electrodetection of small molecules by conformation-mediated signal enhancement

2021 ◽  
Author(s):  
Krishnan Murugappan ◽  
Uthayasuriya Sundaramoorthy ◽  
Adam M Damry ◽  
David R. Nisbet ◽  
Colin J Jackson ◽  
...  
Keyword(s):  
Small Molecules ◽  
Conformational Change ◽  
Electrochemical Biosensors ◽  
Biological Parameters ◽  
New Paradigm ◽  
Electrode Surfaces ◽  
Electrochemical Biosensing ◽  
Wide Range ◽  
Protein Conformational Change ◽  
Molecular Complexity

Electrochemical biosensors allow the rapid, selective, and sensitive transduction of critical biological parameters into measurable signals. However, current electrochemical biosensors often fail to selectively and sensitively detect small molecules due to their small size and low molecular complexity. We have developed an electrochemical biosensing platform that harnesses the analyte-dependent conformational change of highly selective solute-binding proteins to amplify the signal generated by analyte binding. Using this platform, we constructed and characterized two biosensors that can sense leucine and glycine, respectively. We show that these biosensors can selectively and sensitively detect their targets over a wide range of concentrations - up to seven orders of magnitude - and that the selectivity of these sensors can be readily altered by switching the bioreceptor's binding domain. Our work represents a new paradigm for the design of a family of modular electrochemical biosensors, where access to electrode surfaces can be controlled by protein conformational change.

scholarly journals The Role of Peptides in the Design of Electrochemical Biosensors for Clinical Diagnostics

Biosensors ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 246
Author(s):  
Patrick Severin Sfragano ◽  
Giulia Moro ◽  
Federico Polo ◽  
Ilaria Palchetti
Keyword(s):  
Functional Groups ◽  
Synthetic Peptides ◽  
Clinical Diagnostics ◽  
Electrochemical Biosensors ◽  
Practical Application ◽  
Design And Development ◽  
Electrode Surfaces ◽  
Electrochemical Transducers ◽  
Target Analyte

Peptides represent a promising class of biorecognition elements that can be coupled to electrochemical transducers. The benefits lie mainly in their stability and selectivity toward a target analyte. Furthermore, they can be synthesized rather easily and modified with specific functional groups, thus making them suitable for the development of novel architectures for biosensing platforms, as well as alternative labelling tools. Peptides have also been proposed as antibiofouling agents. Indeed, biofouling caused by the accumulation of biomolecules on electrode surfaces is one of the major issues and challenges to be addressed in the practical application of electrochemical biosensors. In this review, we summarise trends from the last three years in the design and development of electrochemical biosensors using synthetic peptides. The different roles of peptides in the design of electrochemical biosensors are described. The main procedures of selection and synthesis are discussed. Selected applications in clinical diagnostics are also described.

scholarly journals Fabrication of Low-Fouling Surfaces on Alkyne-Functionalized Poly-(p-xylylenes) Using Click Chemistry

Polymers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 225
Author(s):  
Pei-Ju Chen ◽  
Hsien-Yeh Chen ◽  
Wei-Bor Tsai
Keyword(s):  
Thin Films ◽  
Conjugated Polymers ◽  
Click Chemistry ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Universal Method ◽  
Surface Immobilization ◽  
Poly Ethylene Glycol ◽  
Wide Range ◽  
Poly Ethylene

A facial, versatile, and universal method that breaks the substrate limits is desirable for antifouling treatment. Thin films of functional poly-p-xylylenes (PPX) that are deposited using chemical vapor deposition (CVD) provide a powerful platform for surface immobilization of molecules. In this study, we prepared an alkyne-functionalized PPX coating on which poly (sulfobetaine methacrylate-co-Az) could be conjugated via click chemistry. We found that the conjugated polymers were very stable and inhibited cell adhesion and protein adsorption effectively. The same conjugation strategy could also be applied to conjugate azide-containing poly (ethylene glycol) and poly (NIPAAm). The results indicate that our method provides a simple and robust tool for fabricating antifouling surfaces on a wide range of substrates using CVD technology of functionalized poly (p-xylylenes) for biosensor, diagnostics, immunoassay, and other biomaterial applications.

scholarly journals Synthesis, stability, and reactivity of mesoionic carbene iridium dihydride complexes

2020 ◽  
Author(s):  
Marta Olivares ◽  
Martin Albrecht
Keyword(s):  
Electronic Properties ◽  
Functional Groups ◽  
Pyridine Ring ◽  
Spectroscopic Analysis ◽  
Pka Values ◽  
Trans Effect ◽  
Structural Assignment ◽  
Wide Range ◽  
Hydride Metal ◽  
The Stability

Pyridyl-triazolylidene ligands with variable donor properties were used as tunable ligands at a dihydride iridium(III) center. The straightforward synthesis of this type of ligand allows for an easy incorporation of electron donating substituents in different positions of the pyridine ring or different functional groups such as esters, alkoxy or aliphatic chains on the C4 position of the triazole heterocycle. The stability of these hydride metal systems allowed these complexes to be used as models for studying the influence of the ligand modifications on hydride reactivity. Spectroscopic analysis provided unambiguous structural assignment of the dihydride system. Modulation of the electronic properties of the wingtip substituents did not appreciably alter the reactivity of the hydrides. Reactivity studies using acids with a wide range of pKa values indicated a correlation between hydride reactivity and acidity and showed exclusive reactivity towards the less shielded hydride trans to the carbene carbon rather than the more shielded hydride trans to the pyridine ring, suggesting that the trans effect is more relevant in these reactions than the NMR spectroscopically deduced hydridic character.

scholarly journals Tuning the electronic properties of monolayer and bilayer PtSe2via strain engineering

2016 ◽  
Vol 4 (15) ◽  
pp. 3106-3112 ◽  
Author(s):  
Pengfei Li ◽  
Lei Li ◽  
Xiao Cheng Zeng
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Strain Engineering ◽  
Band Gaps ◽  
Wide Range

Based on the first-principles computations we show that the band gaps of monolayer and bilayer PtSe2 can be tuned over a wide range via strain engineering.

scholarly journals Prediction of the structural and electronic properties of MoxTi1−xS2 monolayers via first principle simulations

2020 ◽  
Vol 10 ◽  
pp. 184798042095509
Author(s):  
Ankit Kumar Verma ◽  
Federico Raffone ◽  
Giancarlo Cicero
Keyword(s):  
Transition Metal ◽  
Electronic Properties ◽  
Transition Metal Dichalcogenides ◽  
Stable Phase ◽  
Two Dimensional ◽  
Electron Hole ◽  
Effective Electron ◽  
Wide Range ◽  
Structural And Electronic Properties ◽  
Metal Dichalcogenides

Two-dimensional transition metal dichalcogenides have gained great attention because of their peculiar physical properties that make them interesting for a wide range of applications. Lately, alloying between different transition metal dichalcogenides has been proposed as an approach to control two-dimensional phase stability and to obtain compounds with tailored characteristics. In this theoretical study, we predict the phase diagram and the electronic properties of Mo xTi1− xS2 at varying stoichiometry and show how the material is metallic, when titanium is the predominant species, while it behaves as a p-doped semiconductor, when approaching pure MoS2 composition. Correspondingly, the thermodynamically most stable phase switches from the tetragonal to the hexagonal one. Further, we present an example which shows how the proposed alloys can be used to obtain new vertical two-dimensional heterostructures achieving effective electron/hole separation.

scholarly journals A First-Principles Study of Nonlinear Elastic Behavior and Anisotropic Electronic Properties of Two-Dimensional HfS2

Nanomaterials ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 446
Author(s):  
Mahdi Faghihnasiri ◽  
Aidin Ahmadi ◽  
Samaneh Alvankar Golpayegan ◽  
Saeideh Garosi Sharifabadi ◽  
Ali Ramazani
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Electronic Band Structure ◽  
Hexagonal Phase ◽  
Strain Engineering ◽  
Elastic Behavior ◽  
Potential Candidate ◽  
Two Dimensional ◽  
Electronic Band ◽  
Wide Range

We utilize first principles calculations to investigate the mechanical properties and strain-dependent electronic band structure of the hexagonal phase of two dimensional (2D) HfS2. We apply three different deformation modes within −10% to 30% range of two uniaxial (D1, D2) and one biaxial (D3) strains along x, y, and x-y directions, respectively. The harmonic regions are identified in each deformation mode. The ultimate stress for D1, D2, and D3 deformations is obtained as 0.037, 0.038 and 0.044 (eV/Ang3), respectively. Additionally, the ultimate strain for D1, D2, and D3 deformation is obtained as 17.2, 17.51, and 21.17 (eV/Ang3), respectively. In the next step, we determine the second-, third-, and fourth-order elastic constants and the electronic properties of both unstrained and strained HfS2 monolayers are investigated. Our findings reveal that the unstrained HfS2 monolayer is a semiconductor with an indirect bandgap of 1.12 eV. We then tune the bandgap of HfS2 with strain engineering. Our findings reveal how to tune and control the electronic properties of HfS2 monolayer with strain engineering, and make it a potential candidate for a wide range of applications including photovoltaics, electronics and optoelectronics.

scholarly journals Copper(I)-Catalyzed Click Chemistry as a Tool for the Functionalization of Nanomaterials and the Preparation of Electrochemical (Bio)Sensors

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2379 ◽  
Author(s):  
P. Yáñez-Sedeño ◽  
A. González-Cortés ◽  
S. Campuzano ◽  
J. M. Pingarrón
Keyword(s):  
Electrochemical Sensors ◽  
Functional Integration ◽  
Future Directions ◽  
Physiological Conditions ◽  
Electrode Surfaces ◽  
Wide Range ◽  
High Yields ◽  
By Products ◽  
Powerful Strategy

Proper functionalization of electrode surfaces and/or nanomaterials plays a crucial role in the preparation of electrochemical (bio)sensors and their resulting performance. In this context, copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) has been demonstrated to be a powerful strategy due to the high yields achieved, absence of by-products and moderate conditions required both in aqueous medium and under physiological conditions. This particular chemistry offers great potential to functionalize a wide variety of electrode surfaces, nanomaterials, metallophthalocyanines (MPcs) and polymers, thus providing electrochemical platforms with improved electrocatalytic ability and allowing the stable, reproducible and functional integration of a wide range of nanomaterials and/or different biomolecules (enzymes, antibodies, nucleic acids and peptides). Considering the rapid progress in the field, and the potential of this technology, this review paper outlines the unique features imparted by this particular reaction in the development of electrochemical sensors through the discussion of representative examples of the methods mainly reported over the last five years. Special attention has been paid to electrochemical (bio)sensors prepared using nanomaterials and applied to the determination of relevant analytes at different molecular levels. Current challenges and future directions in this field are also briefly pointed out.

Nano-structured GeySi1-y:H Films Deposited by Low Frequency Plasma for Photovoltaic Application

2008 ◽  
Vol 1127 ◽  
Author(s):  
Andrey Kosarev ◽  
Alfonso Torres ◽  
Carlos Zuniga ◽  
Marco Adamo ◽  
Liborio Sanchez
Keyword(s):  
Electronic Properties ◽  
Urbach Energy ◽  
Low Frequency ◽  
Localized States ◽  
Statistical Parameters ◽  
Nano Structure ◽  
Mean Values ◽  
Temperature Dependence Of Conductivity ◽  
Wide Range ◽  
Grain Distribution

ABSTRACTIn this work we present the study of fabrication, Ge incorporation, structure and electronic properties of nano-structured GeySi1-y:H films with y>0.5 prepared by low frequency (LF) PECVD. GeySi1-y:H films were deposited by LF PECVD at a frequency f= 110 kHz from SiH4+GeH4+H2 gas mixture. SiH4 and GeH4 flows were varied to fabricate the films in wide range of 0<y<l. Hydrogen dilution was varied in the range of RH =20 to 80. Structure of the films was studied by AFM and SEM with consequent image processing to extract statistical parameters such as grain distribution and mean values. Composition of the films was characterized by SIMS and EDX. Electronic properties were characterized by temperature dependence of conductivity, spectral dependence of optical absorption. Sub-gap absorption was characterized by Urbach energy, EU; and defect absorption, αD. We observed grain like nano-structure with Gauss distribution of grain diameters by both AFM and SEM measurements. The most interesting films had mean grain diameter<D> = 24.0±0.7 nm, dispersion D=11.0±0.2 nm and fill factor FF=0.313, Ge content y=0.96-0.97(by SIMS and EDS). These films showed also the lowest values of Urbach energy EU = 0.030 eV and low defect absorption αD = 5×102 cm −1 (at photon energy hv = 1.04 eV) indicating on low density of localized states in mobility gap. Doped films have been also fabricated and studied. Finally we shall discuss application of the above films in photovoltaic devices.

scholarly journals Structure-Activity Relationships for the Anaesthetic and Analgaesic Properties of Aromatic Ring-Substituted Ketamine Esters

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2950
Author(s):  
Ivaylo V. Dimitrov ◽  
Martyn G. Harvey ◽  
Logan J. Voss ◽  
James W. Sleigh ◽  
Michael J. Bickerdike ◽  
...  
Keyword(s):  
Electronic Properties ◽  
Benzene Ring ◽  
Aromatic Ring ◽  
Alkyl Esters ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Wide Range ◽  
Powerful Electron ◽  
Electron Withdrawing Substituents

A series of benzene ring substituted ketamine N-alkyl esters were prepared from the corresponding substituted norketamines. Few of the latter have been reported since they have not been generally accessible via known routes. We report a new general route to many of these norketamines via the Neber (oxime to α-aminoketone) rearrangement of readily available substituted 2-phenycyclohexanones. We explored the use of the substituents Cl, Me, OMe, CF3, and OCF3, with a wide range of lipophilic and electronic properties, at all available benzene ring positions. The 2- and 3-substituted compounds were generally more active than 4-substituted compounds. The most generally acceptable substituent was Cl, while the powerful electron-withdrawing substituents CF3 and OCF3 provided fewer effective analogues.

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