A Highly Selective Potassium Sensor for the Detection of Potassium in Living Tissues

2016 ◽  
Vol 22 (42) ◽  
pp. 14902-14911 ◽  
Author(s):  
Alexis Depauw ◽  
Elena Dossi ◽  
Naresh Kumar ◽  
Céline Fiorini-Debuisschert ◽  
Gilles Huberfeld ◽  
...  
Keyword(s):  
Potassium Sensor ◽  
Living Tissues

Low-voltage field-emission SEM of polymeric membranes for glucose biosensors

1990 ◽  
Vol 48 (3) ◽  
pp. 860-861
Author(s):  
Lorna K. Mayo ◽  
Kenneth C. Moore ◽  
Mark A. Arnold
Keyword(s):  
Glucose Sensor ◽  
Low Voltage ◽  
Glucose Sensors ◽  
Polymeric Membranes ◽  
Artificial Endocrine Pancreas ◽  
Self Monitoring ◽  
Conducting Materials ◽  
Insulin Dependent ◽  
Living Tissues ◽  
Voltage Scanning

An implantable artificial endocrine pancreas consisting of a glucose sensor and a closed-loop insulin delivery system could potentially replace the need for glucose self-monitoring and regulation among insulin dependent diabetics. Achieving such a break through largely depends on the development of an appropriate, biocompatible membrane for the sensor. Biocompatibility is crucial since changes in the glucose sensors membrane resulting from attack by orinter action with living tissues can interfere with sensor reliability and accuracy. If such interactions can be understood, however, compensations can be made for their effects. Current polymer technology offers several possible membranes that meet the unique chemical dynamics required of a glucose sensor. Two of the most promising polymer membranes are polytetrafluoroethylene (PTFE) and silicone (Si). Low-voltage scanning electron microscopy, which is an excellent technique for characterizing a variety of polymeric and non-conducting materials, 27 was applied to the examination of experimental sensor membranes.

Matrix metalloproteinases in stroke

2017 ◽  
pp. 110-117
Author(s):  
А.А. Пальцын
Keyword(s):  
Matrix Metalloproteinases ◽  
Enzyme System ◽  
Enzyme Complex ◽  
Pathogenic Factors ◽  
Pathogenic Action ◽  
Activity Of Enzymes ◽  
Living Tissues ◽  
Current Reconstruction ◽  
Metalloproteinase Activity

Матриксные металлопротеиназы - ферментный комплекс, необходимый для сохранения гомеостаза. Он участник нормальной, постоянно текущей реконструкции всех живых тканей. Действие патогенных факторов нарушает слаженную работу этого комплекса. Часто нарушение выражается излишней активностью ферментов, усиливающей патогенное действие. Однако и заживление, форсированное новообразование тканевых элементов, может происходить только при повышенной, в сравнении с нормой, активности металлопротеиназ. Такая ситуация требует от медицины умения разумно вмешиваться в работу ферментной системы. В статье представлены некоторые результаты этих вмешательств. Matrix metalloproteinases - enzyme complex necessary for maintenance of the homeostasis. He is a participant of normal, constantly current reconstruction of all living tissues. Action of pathogenic factors breaks harmonious work of this complex. Often violation is expressed by the excessive activity of enzymes amplifying pathogenic action. However and healing, which is accelerated new growth of tissue elements, can happen only at raised, compared with norm, metalloproteinase activity. Such situation demands from medicine of ability participate reasonably in work of enzyme system. The article presents some of the results of these actions.

scholarly journals Survival and Proliferation under Severely Hypoxic Microenvironments Using Cell-Laden Oxygenating Hydrogels

2021 ◽  
Vol 12 (2) ◽  
pp. 30
Author(s):  
Shabir Hassan ◽  
Berivan Cecen ◽  
Ramon Peña-Garcia ◽  
Fernanda Roberta Marciano ◽  
Amir K. Miri ◽  
...  
Keyword(s):  
Prolonged Release ◽  
Therapeutic Approaches ◽  
Encapsulated Cells ◽  
Hypoxic Conditions ◽  
Skeletal Myoblasts ◽  
Artificial Tissue ◽  
Delivery Platform ◽  
Living Tissues

Different strategies have been employed to provide adequate nutrients for engineered living tissues. These have mainly revolved around providing oxygen to alleviate the effects of chronic hypoxia or anoxia that result in necrosis or weak neovascularization, leading to failure of artificial tissue implants and hence poor clinical outcome. While different biomaterials have been used as oxygen generators for in vitro as well as in vivo applications, certain problems have hampered their wide application. Among these are the generation and the rate at which oxygen is produced together with the production of the reaction intermediates in the form of reactive oxygen species (ROS). Both these factors can be detrimental for cell survival and can severely affect the outcome of such studies. Here we present calcium peroxide (CPO) encapsulated in polycaprolactone as oxygen releasing microparticles (OMPs). While CPO releases oxygen upon hydrolysis, PCL encapsulation ensures that hydrolysis takes place slowly, thereby sustaining prolonged release of oxygen without the stress the bulk release can endow on the encapsulated cells. We used gelatin methacryloyl (GelMA) hydrogels containing these OMPs to stimulate survival and proliferation of encapsulated skeletal myoblasts and optimized the OMP concentration for sustained oxygen delivery over more than a week. The oxygen releasing and delivery platform described in this study opens up opportunities for cell-based therapeutic approaches to treat diseases resulting from ischemic conditions and enhance survival of implants under severe hypoxic conditions for successful clinical translation.

scholarly journals The emerging technology of biohybrid micro-robots: a review

2021 ◽  
Author(s):  
Zening Lin ◽  
Tao Jiang ◽  
Jianzhong Shang
Keyword(s):  
Self Assembly ◽  
Degrees Of Freedom ◽  
High Energy ◽  
Living Cells ◽  
Multiple Degrees Of Freedom ◽  
The Past ◽  
Great Prevalence ◽  
Performance Decline ◽  
High Energy Efficiency ◽  
Living Tissues

Abstract In the past few decades, robotics research has witnessed an increasingly high interest in miniaturized, intelligent, and integrated robots. The imperative component of a robot is the actuator that determines its performance. Although traditional rigid drives such as motors and gas engines have shown great prevalence in most macroscale circumstances, the reduction of these drives to the millimeter or even lower scale results in a significant increase in manufacturing difficulty accompanied by a remarkable performance decline. Biohybrid robots driven by living cells can be a potential solution to overcome these drawbacks by benefiting from the intrinsic microscale self-assembly of living tissues and high energy efficiency, which, among other unprecedented properties, also feature flexibility, self-repair, and even multiple degrees of freedom. This paper systematically reviews the development of biohybrid robots. First, the development of biological flexible drivers is introduced while emphasizing on their advantages over traditional drivers. Second, up-to-date works regarding biohybrid robots are reviewed in detail from three aspects: biological driving sources, actuator materials, and structures with associated control methodologies. Finally, the potential future applications and major challenges of biohybrid robots are explored. Graphic abstract

scholarly journals Hyperspectral Imagery for Assessing Laser-Induced Thermal State Change in Liver

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 643
Author(s):  
Martina De Landro ◽  
Ignacio Espíritu García-Molina ◽  
Manuel Barberio ◽  
Eric Felli ◽  
Vincent Agnus ◽  
...  
Keyword(s):  
Thermal Damage ◽  
Thermal State ◽  
Preliminary Investigation ◽  
Spectral Band ◽  
Spectral Variation ◽  
Ablation Therapy ◽  
Clinical Endpoints ◽  
Breathing Motion ◽  
Living Tissues

This work presents the potential of hyperspectral imaging (HSI) to monitor the thermal outcome of laser ablation therapy used for minimally invasive tumor removal. Our main goal is the establishment of indicators of the thermal damage of living tissues, which can be used to assess the effect of the procedure. These indicators rely on the spectral variation of temperature-dependent tissue chromophores, i.e., oxyhemoglobin, deoxyhemoglobin, methemoglobin, and water. Laser treatment was performed at specific temperature thresholds (from 60 to 110 °C) on in-vivo animal liver and was assessed with a hyperspectral camera (500–995 nm) during and after the treatment. The indicators were extracted from the hyperspectral images after the following processing steps: the breathing motion compensation and the spectral and spatial filtering, the selection of spectral bands corresponding to specific tissue chromophores, and the analysis of the areas under the curves for each spectral band. Results show that properly combining spectral information related to deoxyhemoglobin, methemoglobin, lipids, and water allows for the segmenting of different zones of the laser-induced thermal damage. This preliminary investigation provides indicators for describing the thermal state of the liver, which can be employed in the future as clinical endpoints of the procedure outcome.

scholarly journals Nuclear Stiffness Decreases with Disruption of the Extracellular Matrix in Living Tissues

Small ◽  
2021 ◽  
Vol 17 (6) ◽  
pp. 2006699
Author(s):  
Kaitlin P. McCreery ◽  
Xin Xu ◽  
Adrienne K. Scott ◽  
Apresio K. Fajrial ◽  
Sarah Calve ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Living Tissues

scholarly journals Nonlinear multiscale simulation of instabilities due to growth of an elastic film on a microstructured substrate

2020 ◽  
Vol 90 (11) ◽  
pp. 2397-2412
Author(s):  
Iman Valizadeh ◽  
Oliver Weeger
Keyword(s):  
Deformation Gradient ◽  
Multiscale Simulation ◽  
Numerical Results ◽  
Unit Cell ◽  
Homogeneous Material ◽  
Two Phase ◽  
Biological Phenomena ◽  
Elastic Film ◽  
Living Tissues ◽  
Analytical Approaches

Abstract The objective of this contribution is the numerical investigation of growth-induced instabilities of an elastic film on a microstructured soft substrate. A nonlinear multiscale simulation framework is developed based on the FE2 method, and numerical results are compared against simplified analytical approaches, which are also derived. Living tissues like brain, skin, and airways are often bilayered structures, consisting of a growing film on a substrate. Their modeling is of particular interest in understanding biological phenomena such as brain development and dysfunction. While in similar studies the substrate is assumed as a homogeneous material, this contribution considers the heterogeneity of the substrate and studies the effect of microstructure on the instabilities of a growing film. The computational approach is based on the mechanical modeling of finite deformation growth using a multiplicative decomposition of the deformation gradient into elastic and growth parts. Within the nonlinear, concurrent multiscale finite element framework, on the macroscale a nonlinear eigenvalue analysis is utilized to capture the occurrence of instabilities and corresponding folding patterns. The microstructure of the substrate is considered within the large deformation regime, and various unit cell topologies and parameters are studied to investigate the influence of the microstructure of the substrate on the macroscopic instabilities. Furthermore, an analytical approach is developed based on Airy’s stress function and Hashin–Shtrikman bounds. The wavelengths and critical growth factors from the analytical solution are compared with numerical results. In addition, the folding patterns are examined for two-phase microstructures and the influence of the parameters of the unit cell on the folding pattern is studied.

scholarly journals The action of anæsthetics on living tissues. Part I.— The action on isolated nerve

1906 ◽  
Vol 77 (517) ◽  
pp. 267-283 ◽  
Keyword(s):  
Carbon Dioxide ◽  
General Question ◽  
Nerve Action ◽  
Physical Action ◽  
The Subject ◽  
Living Tissues

The action of anaesthetics on isolated nerve has already been studied by Waller* as regards the effect on the negative variation in the sciatic of the frog, and by myself in mammalian nerves.f In the course of these researches it became evident that the anaesthetics used (chloroform, ether, carbon dioxide) affected not only the negative variation, but also the injury current, and as this action has not been studied before, as far as I am aware, it seemed desirable to investigate the matter not only in nerve, but also in other tissues. The inquiry falls naturally under two heads: first, in how far the phenomena throw light on the processes of nerve action ; and, secondly, as regards the chemical and physical action of anaesthetics on the animal protoplasm generally. These are obviously only parts of the same story, but for convenience I have considered the subject mainly under the first heading in this part, leaving the more general question to a future occasion.

Repeatability, Reproducibility, and Calibration of the MyotonPro® on Tissue Mimicking Phantoms

2013 ◽  
Author(s):  
John Dougherty ◽  
Emily Schaefer ◽  
Kalyani Nair ◽  
Joseph Kelly ◽  
Alfonse Masi
Keyword(s):  
Data Collection ◽  
Dynamic Stiffness ◽  
Correlation Study ◽  
Living Tissue ◽  
Polymeric Gel ◽  
Stiffness Properties ◽  
Tissue Phantoms ◽  
Repeatability And Reproducibility ◽  
Living Tissues

The MyotonPro® (Myoton AS, Tallinn, Estonia) is commonly used to quantify stiffness properties of living tissues in situ. Current studies quantify the dynamic stiffness properties of living tissues, but do not validate or compare these measurements to a standardized method. Additionally, living tissue, being dynamic in nature, presents much variability in data collection. To address these issues this study focuses on the repeatability and reproducibility of the MyotonPro® on polymeric gel-based tissue phantoms. In addition, a correlation study is also performed to translate dynamic stiffness to a more standardized property, Young’s modulus. Such studies help to confirm the reliability of the measurements obtained in situ.

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