scholarly journals Ion-to-ion amplification through an open-junction ionic diode

2019 ◽  
Vol 116 (28) ◽  
pp. 13807-13815 ◽  
Author(s):  
Seung-Min Lim ◽  
Hyunjae Yoo ◽  
Min-Ah Oh ◽  
Seok Hee Han ◽  
Hae-Ryung Lee ◽  
...  
Keyword(s):  
Signal Amplification ◽  
Biological Systems ◽  
External Environment ◽  
Ionic Currents ◽  
Ion Injection ◽  
Ionic Systems ◽  
Electrical Devices ◽  
Effective Signal ◽  
Junction Structure ◽  
Polyelectrolyte Hydrogel

As biological signals are mainly based on ion transport, the differences in signal carriers have become a major issue for the intimate communication between electrical devices and biological areas. In this respect, an ionic device which can directly interpret ionic signals from biological systems needs to be designed. Particularly, it is also required to amplify the ionic signals for effective signal processing, since the amount of ions acquired from biological systems is very small. Here, we report the signal amplification in ionic systems as well as sensing through the modified design of polyelectrolyte hydrogel-based ionic diodes. By designing an open-junction structure, ionic signals from the external environment can be directly transmitted to an ionic diode. Moreover, the minute ionic signals injected into the devices can also be amplified to a large amount of ions. The signal transduction mechanism of the ion-to-ion amplification is suggested and clearly verified by revealing the generation of breakdown ionic currents during an ion injection. Subsequently, various methods for enhancing the amplification are suggested.

K-junction structure mediated exponential signal amplification strategy for microRNA detection in electrochemiluminescence biosensor

The Analyst ◽  
2017 ◽  
Vol 142 (12) ◽  
pp. 2185-2190 ◽  
Author(s):  
Xue Li ◽  
Anyi Chen ◽  
Yaqin Chai ◽  
Ruo Yuan
Keyword(s):  
Signal Amplification ◽  
The Novel ◽  
Microrna Detection ◽  
G Quadruplex ◽  
Simple Protocol ◽  
Amplification Strategy ◽  
Junction Structure

Based on the novel designed K-junction structure, an economic and efficient exponential signal amplification strategy with simple protocol combining hemin/G-quadruplex, a mimetic peroxidase, as a catalyzer was proposed and utilized in an electrochemiluminescence biosensor for sensitive microRNA detection.

scholarly journals An Experimental and Numerical Study of Polyelectrolyte Hydrogel Ionic Diodes: Towards Electrical Detection of Charged Biomolecules

Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8279
Author(s):  
Chenwei Xiong ◽  
Boyin Zhang ◽  
Rong Zhang ◽  
Yifan Liu
Keyword(s):  
Numerical Simulation ◽  
Numerical Study ◽  
Ionic Current ◽  
Ionic Currents ◽  
Microfluidic Chips ◽  
Electrical Detection ◽  
Heterogeneous Distribution ◽  
Transport Of Ions ◽  
Current Rectification ◽  
Polyelectrolyte Hydrogel

Polyelectrolyte hydrogel ionic diodes (PHIDs) have recently emerged as a unique set of iontronic devices. Such diodes are built on microfluidic chips that feature polyelectrolyte hydrogel junctions and rectify ionic currents owing to the heterogeneous distribution and transport of ions across the junctions. In this paper, we provide the first account of a study on the ion transport behavior of PHIDs through an experimental investigation and numerical simulation. The effects of bulk ionic strength and hydrogel pore confinement are experimentally investigated. The ionic current rectification (ICR) exhibits saturation in a micromolar regime and responds to hydrogel pore size, which is subsequently verified in a simulation. Furthermore, we experimentally show that the rectification is sensitive to the dose of immobilized DNA with an exhibited sensitivity of 1 ng/μL. We anticipate our findings would be beneficial to the design of PHID-based biosensors for electrical detection of charged biomolecules.

Phase reversal of vibratory signals in honeycomb may assist dancing honeybees to attract their audience

2001 ◽  
Vol 204 (21) ◽  
pp. 3737-3746
Author(s):  
J. Tautz ◽  
J. Casas ◽  
D. Sandeman
Keyword(s):  
Signal Amplification ◽  
Visual Signals ◽  
Signal Source ◽  
Phase Reversal ◽  
Reversal Phenomenon ◽  
A Cell ◽  
Effective Signal ◽  
Single Comb ◽  
Specific Distance ◽  
Vibratory Signals

SUMMARY Forager honeybees dancing on the comb are able to attract dance-followers from distances across the comb that are too remote for tactile or visual signals to play a role. An alternative signal could be the vibrations of the comb at 200–300 Hz generated by dancing bees but which, without amplification, may not be large enough to alert remote dance-followers. We describe here, however, an unexpected property of honeycomb when it is subjected to vibration at around 200 Hz that would represent an effective amplification of the vibratory signals for remote dance-followers. We find that, at a specific distance from the origin of an imposed vibration, the walls across a single comb cell abruptly reverse the phase of their displacement and move in opposite directions to one another. Behavioural measurements show that the distance from which the majority of remote dance-followers are recruited coincides with the location of this phase-reversal phenomenon relative to the signal source. We propose that effective signal amplification by the phase-reversal phenomenon occurs when bees straddle a cell across which the phase reversal is expressed. Such a bee would be subjected to a situation in which the legs were moving towards and away from one another instead of in the same direction. In this manner, remote dance-followers could be alerted to a dancer performing in their vicinity.

scholarly journals A Reduction-Sensitive Fluorous Fluorogenic Coumarin

Synlett ◽  
2019 ◽  
Vol 31 (05) ◽  
pp. 450-454
Author(s):  
Margeaux A. Miller ◽  
Rachael A. Day ◽  
Daniel A. Estabrook ◽  
Ellen M. Sletten
Keyword(s):  
Drug Delivery ◽  
Biological Systems ◽  
External Environment ◽  
Reducing Agents ◽  
Core Shell ◽  
Chemical Changes ◽  
Drug Delivery Vehicles ◽  
Delivery Vehicles ◽  
Perfluorocarbon Nanoemulsions

Fluorophores that are sensitive to their environment are useful tools for sensing chemical changes and probing biological systems. Here, we extend responsive fluorophores to the fluorous phase with the synthesis of a reduction-sensitive fluorous-soluble fluorogenic coumarin. We demonstrate that this fluorophore responds to various reducing agents, most notably glutathione, a key biological reductant. The fluorous solubility of this probe allows for its encapsulation into two different fluorous nanomaterials: perfluorocarbon nanoemulsions and fluorous core-shell micelles. The fluorogenic coumarin allows us to study how efficiently these vehicles protect the contents of their interior from the external environment. In the presence of glutathione, we observe different degrees of release for micelles and emulsions. This understanding will help guide future applications of fluorous nanomaterials as drug delivery vehicles.

scholarly journals Signal Amplification in Highly Ordered Networks Is Driven by Geometry

Cells ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 272
Author(s):  
Éva S. Vanamee ◽  
Gábor Lippner ◽  
Denise L. Faustman
Keyword(s):  
Signal Amplification ◽  
Planar Graphs ◽  
Biological Systems ◽  
Maximum Efficiency ◽  
Signaling Networks ◽  
Surface Receptors ◽  
Fundamental Relationship ◽  
External Signals ◽  
Clustered Systems ◽  
Signaling Efficiency

Here, we hypothesize that, in biological systems such as cell surface receptors that relay external signals, clustering leads to substantial improvements in signaling efficiency. Representing cooperative signaling networks as planar graphs and applying Euler’s polyhedron formula, we can show that clustering may result in an up to a 200% boost in signaling amplitude dictated solely by the size and geometry of the network. This is a fundamental relationship that applies to all clustered systems regardless of its components. Nature has figured out a way to maximize the signaling amplitude in receptors that relay weak external signals. In addition, in cell-to-cell interactions, clustering both receptors and ligands may result in maximum efficiency and synchronization. The importance of clustering geometry in signaling efficiency goes beyond biological systems and can inform the design of amplifiers in nonbiological systems.

Transmission Electron Microscopy of Protein Macromolecules

1971 ◽  
Vol 29 ◽  
pp. 424-425
Author(s):  
Henry S. Slayter
Keyword(s):  
Biological Systems ◽  
Metal Vapor ◽  
Resolving Power ◽  
Electron Microscopic ◽  
Chemical Methods ◽  
Molecular Weights ◽  
The Past ◽  
Physical Chemical ◽  
Transmission Electron

Electron microscopic methods have been applied increasingly during the past fifteen years, to problems in structural molecular biology. Used in conjunction with physical chemical methods and/or Fourier methods of analysis, they constitute powerful tools for determining sizes, shapes and modes of aggregation of biopolymers with molecular weights greater than 50, 000. However, the application of the e.m. to the determination of very fine structure approaching the limit of instrumental resolving power in biological systems has not been productive, due to various difficulties such as the destructive effects of dehydration, damage to the specimen by the electron beam, and lack of adequate and specific contrast. One of the most satisfactory methods for contrasting individual macromolecules involves the deposition of heavy metal vapor upon the specimen. We have investigated this process, and present here what we believe to be the more important considerations for optimizing it. Results of the application of these methods to several biological systems including muscle proteins, fibrinogen, ribosomes and chromatin will be discussed.

Advances in Microprobe Analysis Applied to Muscle, Nerve and Gland

1982 ◽  
Vol 40 ◽  
pp. 404-407
Author(s):  
T. E. Hutchinson ◽  
D. E. Johnson ◽  
A. C. Lee ◽  
E. Y. Wang
Keyword(s):  
Biological Tissue ◽  
Microprobe Analysis ◽  
Physiological State ◽  
External Environment ◽  
Physiological Relevance ◽  
Muscle Nerve ◽  
Technique Development

Microprobe analysis of biological tissue is now in the end phase of transition from instrumental and technique development to applications pertinent to questions of physiological relevance. The promise,implicit in early investigative efforts, is being fulfilled to an extent much greater than many had predicted. It would thus seem appropriate to briefly report studies exemplifying this, ∿. In general, the distributions of ions in tissue in a preselected physiological state produced by variations in the external environment is of importance in elucidating the mechanisms of exchange and regulation of these ions.

Microanatomy of the Periplasm of Bacillus Licheniformis

1971 ◽  
Vol 29 ◽  
pp. 262-263
Author(s):  
B.K. Ghosh
Keyword(s):  
Cell Wall ◽  
Plasma Membrane ◽  
Bacillus Licheniformis ◽  
External Environment ◽  
Permeability Barrier ◽  
Periplasmic Space ◽  
Modified Technique ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria

Periplasm of bacteria is the space outside the permeability barrier of plasma membrane but enclosed by the cell wall. The contents of this special milieu exterior could be regulated by the plasma membrane from the internal, and by the cell wall from the external environment of the cell. Unlike the gram-negative organism, the presence of this space in gram-positive bacteria is still controversial because it cannot be clearly demonstrated. We have shown the importance of some periplasmic bodies in the secretion of penicillinase from Bacillus licheniformis.In negatively stained specimens prepared by a modified technique (Figs. 1 and 2), periplasmic space (PS) contained two kinds of structures: (i) fibrils (F, 100 Å) running perpendicular to the cell wall from the protoplast and (ii) an array of vesicles of various sizes (V), which seem to have evaginated from the protoplast.

Freeze-fracture cytochemistry: A goal set by Russell Steere in 1957

1993 ◽  
Vol 51 ◽  
pp. 60-61
Author(s):  
Nicholas J Severs
Keyword(s):  
Chemical Nature ◽  
Biological Systems ◽  
Freeze Fracture ◽  
Structural Components ◽  
Major Goal ◽  
Membrane Biology ◽  
Routine Application ◽  
The Future ◽  
Freeze Etching

In his pioneering demonstration of the potential of freeze-etching in biological systems, Russell Steere assessed the future promise and limitations of the technique with remarkable foresight. Item 2 in his list of inherent difficulties as they then stood stated “The chemical nature of the objects seen in the replica cannot be determined”. This defined a major goal for practitioners of freeze-fracture which, for more than a decade, seemed unattainable. It was not until the introduction of the label-fracture-etch technique in the early 1970s that the mould was broken, and not until the following decade that the full scope of modern freeze-fracture cytochemistry took shape. The culmination of these developments in the 1990s now equips the researcher with a set of effective techniques for routine application in cell and membrane biology.Freeze-fracture cytochemical techniques are all designed to provide information on the chemical nature of structural components revealed by freeze-fracture, but differ in how this is achieved, in precisely what type of information is obtained, and in which types of specimen can be studied.

Seeking to uncover biology's chemical roots

2019 ◽  
Vol 3 (5) ◽  
pp. 435-443 ◽  
Author(s):  
Addy Pross
Keyword(s):  
Environmental Changes ◽  
Biological Systems ◽  
Significant Development ◽  
The Road ◽  
Physical Chemical ◽  
Systems Chemistry ◽  
Biological World ◽  
Inanimate Matter ◽  
The Origin Of Life ◽  
Opening Up

Despite the considerable advances in molecular biology over the past several decades, the nature of the physical–chemical process by which inanimate matter become transformed into simplest life remains elusive. In this review, we describe recent advances in a relatively new area of chemistry, systems chemistry, which attempts to uncover the physical–chemical principles underlying that remarkable transformation. A significant development has been the discovery that within the space of chemical potentiality there exists a largely unexplored kinetic domain which could be termed dynamic kinetic chemistry. Our analysis suggests that all biological systems and associated sub-systems belong to this distinct domain, thereby facilitating the placement of biological systems within a coherent physical/chemical framework. That discovery offers new insights into the origin of life process, as well as opening the door toward the preparation of active materials able to self-heal, adapt to environmental changes, even communicate, mimicking what transpires routinely in the biological world. The road to simplest proto-life appears to be opening up.

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