Non-Invasive Measurement Techniques for Measuring Bilayers in Droplet-Interface-Bilayers

2009 ◽  
Author(s):  
M. Austin Creasy ◽  
Donald J. Leo
Keyword(s):  
Lipid Membranes ◽  
Measurement Techniques ◽  
Building Blocks ◽  
Invasive Technique ◽  
Impedance Measurements ◽  
Synthetic Membranes ◽  
Non Invasive ◽  
Droplet Interface Bilayer ◽  
A Cell ◽  
Living Organisms

Phospholipids and membrane proteins are two of the fundamental building blocks of cell membranes in living organisms. These molecules are amphipathic and synthetic membranes made of phospholipids, called bilayer lipid membranes (BLMs), are used to understand the characteristics of a cell membrane. Studies of these BLMs have been performed on both solid support and liquid support systems. A droplet interface bilayer (DIB) is a liquid support system where a monolayer is formed around a water droplet placed in oil and a bilayer is formed when two of these droplets are placed in contact. For impedance measurements, electrodes are placed in the water on each side of the bilayer. The measurements first insure there is a bilayer and second to obtain information about the bilayer. In a DIB system the electrodes pierce the monolayer surrounding the droplet causing instabilities in the monolayer. This study focuses on a non-invasive technique for measuring the bilayer by using the electrodes to contact the monolayer around the droplets and take impedance measurements without piercing the monolayer.

scholarly journals Self-reproducing catalyst drives repeated phospholipid synthesis and membrane growth

2015 ◽  
Vol 112 (27) ◽  
pp. 8187-8192 ◽  
Author(s):  
Michael D. Hardy ◽  
Jun Yang ◽  
Jangir Selimkhanov ◽  
Christian M. Cole ◽  
Lev S. Tsimring ◽  
...  
Keyword(s):  
Lipid Synthesis ◽  
Building Blocks ◽  
Phospholipid Bilayer ◽  
Phospholipid Synthesis ◽  
Synthetic Membranes ◽  
Design And Synthesis ◽  
Membrane Growth ◽  
Membrane Bound ◽  
Living Organisms ◽  
Dynamic Structures

Cell membranes are dynamic structures found in all living organisms. There have been numerous constructs that model phospholipid membranes. However, unlike natural membranes, these biomimetic systems cannot sustain growth owing to an inability to replenish phospholipid-synthesizing catalysts. Here we report on the design and synthesis of artificial membranes embedded with synthetic, self-reproducing catalysts capable of perpetuating phospholipid bilayer formation. Replacing the complex biochemical pathways used in nature with an autocatalyst that also drives lipid synthesis leads to the continual formation of triazole phospholipids and membrane-bound oligotriazole catalysts from simpler starting materials. In addition to continual phospholipid synthesis and vesicle growth, the synthetic membranes are capable of remodeling their physical composition in response to changes in the environment by preferentially incorporating specific precursors. These results demonstrate that complex membranes capable of indefinite self-synthesis can emerge when supplied with simpler chemical building blocks.

scholarly journals Low Cost Non-İnvasive Portable Monitor Platform for Cardiac Biopotential and Transthoracic Impedance Measurements

2021 ◽  
Author(s):  
Oya Köksal ◽  
Erdem Haberal
Keyword(s):  
Reference Value ◽  
Raspberry Pi ◽  
Invasive Technique ◽  
Impedance Change ◽  
Thoracic Impedance ◽  
Current Frequency ◽  
Impedance Measurements ◽  
Non Invasive ◽  
Thoracic Electrical Bioimpedance ◽  
Electrical Bioimpedance

Abstract Purpose Simultaneous monitoring of ECG and thoracic electrical bioimpedance (TEB) is important in evaluating cardiovascular performance. TEB is a non-invasive technique based on measuring the impedance value that changes in the chest area depending on the heartbeat. Within the framework of this study, it can be used in home monitoring and biotelemetry applications to measure thoracic electrical bioimpedance (TEB), ECG and ICG. Methods Within the scope of this study, a four-electrode TEB measurement system was designed and built using the Raspberry Pi single board computer and its original monitor, ESP32 and EVAL-ADAS1000SDZ evaluation board. With the designed system, ECG and thoracic impedance measurements at 50 kHz current frequency were taken as real-time over a single channel. Delta_Z and ICG signals were created from thoracic impedance values with the developed software.ResultsWhile the thoracic impedance value varies between 15-45 Ω, the 67 thoracic impedance value measured with the designed system is approximately 1000 times the 68 reference value. The impedance change in the thoracic region was measured with the designed 69 system between 0.1-0.2 Ω values, and the compatibility of these values with reference values was 70 determined. While the reference value of the dZ / dt signal is 0.8 - 3.5 Ω / s, this value is between 2.3 - 71 5.3 Ω / s in the measurements taken with the designed system.Conclusion The prototype is achieved in detecting small changes in the thoracic impedance signal. The prototype is cheap, portable, small-sized and medically safe, so it is suitable for home care services and clinics. In addition, the developed system can be adapted to wearable technology. In order to increase the success of the system, the impedances values added to the thoracic impedance value should be determined and a calibration procedure should be established.

Review of non-invasive intracranial pressure measurement techniques for ophthalmology applications

2019 ◽  
Vol 104 (7) ◽  
pp. 887-892
Author(s):  
David Andrew Price ◽  
Andrzej Grzybowski ◽  
Jennifer Eikenberry ◽  
Ingrida Januleviciene ◽  
Alice Chandra Verticchio Vercellin ◽  
...  
Keyword(s):  
Intracranial Pressure ◽  
Measurement Techniques ◽  
Optic Nerve Sheath Diameter ◽  
Transcranial Ultrasound ◽  
Invasive Technique ◽  
Non Invasive ◽  
Nerve Sheath ◽  
Assessment And Monitoring ◽  
Invasive Techniques ◽  
The Relationship

Assessment and monitoring of intracranial pressure (ICP) are important in the management of traumatic brain injury and other cerebral pathologies. In the eye, ICP elevation and depression both correlate with optic neuropathies, the former because of papilledema and the latter related to glaucoma. While the relationship between ICP elevation and papilledema is well established, the relationship between low ICP and glaucoma is still poorly understood. So far, ICP monitoring is performed invasively, but this entails risks including infection, spurring the study of non-invasive alternatives. We review 11 methods of non-invasive estimation of ICP including correlation to optic nerve sheath diameter, intraocular pressure, ophthalmodynamometry and two-depth transcranial Doppler of the ophthalmic artery. While none of these methods can fully replace invasive techniques, certain measures show great potential for specific applications. Although only used in small studies to date, a MRI based method known as MR-ICP, appears to be the best non-invasive technique for estimating ICP, with two-depth transcranial ultrasound and ophthalmodynamometry showing potential as well.

Cardiac Output Measured by Transthoracic Impedance Cardiography at Rest, during Exercise and at Various Lung Volumes

1982 ◽  
Vol 63 (2) ◽  
pp. 107-113 ◽  
Author(s):  
A. T. Edmunds ◽  
S. Godfrey ◽  
Marion Tooley
Keyword(s):  
Cardiac Output ◽  
Lung Volume ◽  
Impedance Cardiography ◽  
Close Correlation ◽  
Invasive Technique ◽  
Breath Holding ◽  
Impedance Measurements ◽  
Respiratory Illnesses ◽  
Non Invasive ◽  
Transthoracic Impedance

1. Cardiac output measured by transthoracic impedance cardiography has been compared with simultaneous measurements made by the indirect Fick CO2 rebreathing method in nine adults and 14 children. All were healthy normal volunteers. Sixty-six comparisons were made at rest and during steady exercise at work loads up to 100 W. 2. Impedance measurements of cardiac output were consistently higher than indirect Fick measurements of cardiac output, but after application of a correction factor related to packed cell volume there was close correlation between the results obtained by the two methods (r = 0·94). 3. The mean coefficient of variation of impedance measurements of cardiac output was 13% at rest and 5% during steady-state exercise. 4. Changes of lung volume due to breath holding or resulting from addition of an expiratory resistance did not affect the measurement of cardiac output by impedance. 5. Transthoracic impedance cardiography is a rapid, non-invasive technique for measurement of cardiac output. It requires very little active co-operation from the subject. The method would probably give reliable results for patients with respiratory illnesses such as acute asthma or bronchiolitis, during which changes of lung volume may be expected to occur.

Redox Reactions in Lipid Membranes as a Model for Primordial Energy-Conserving Systems

1997 ◽  
Vol 161 ◽  
pp. 437-442
Author(s):  
Salvatore Di Bernardo ◽  
Romana Fato ◽  
Giorgio Lenaz
Keyword(s):  
Experimental Evidence ◽  
Lipid Membranes ◽  
Energy Supply ◽  
Redox Reactions ◽  
Living Systems ◽  
Asymmetric Distribution ◽  
Conservation Of Energy ◽  
Asymmetrical Distribution ◽  
Energy Conserving ◽  
Living Organisms

AbstractOne of the peculiar aspects of living systems is the production and conservation of energy. This aspect is provided by specialized organelles, such as the mitochondria and chloroplasts, in developed living organisms. In primordial systems lacking specialized enzymatic complexes the energy supply was probably bound to the generation and maintenance of an asymmetric distribution of charged molecules in compartmentalized systems. On the basis of experimental evidence, we suggest that lipophilic quinones were involved in the generation of this asymmetrical distribution of charges through vectorial redox reactions across lipid membranes.

USING DOPPLER TO ASSESS THE FETAL HEALTH FOR THE PREDICTION OF GESTATIONAL OUTCOME

2014 ◽  
pp. 9-18
Author(s):  
Thi Linh Giang Truong ◽  
Vu Quoc Huy Nguyen
Keyword(s):  
Middle Cerebral Artery ◽  
Cerebral Artery ◽  
Umbilical Artery ◽  
Functional Method ◽  
Invasive Technique ◽  
Routine Practice ◽  
Fetal Health ◽  
Uterine Arteries ◽  
Non Invasive ◽  
Key Words Doppler

Background: Assessment of fetal health plays the most important role in prenatal care because of influence of the prediction of gestational outcome. One of the main aims of routine antenatal care is to identify the ‘ at risk ‘ fetus in order to apply clinical interventions which could results in reduced perinatal morbidity and mortality. Doppler ultrasound is a non invasive technique whereby the movement of blood is studied by detecting the change in frequence of reflected sound, Doppler blood flow velocity waves form of fetal side (umbilical artery, middle cerebral artery ...) and maternal side ( uterine arteries) are discussed and monograms for routine practice are presented. Recently this method is important tool for qualifying high risk pregnancies and help early forecasts the health of the babies and mothers disorder. Doppler sonography in obstetrics is a widely accepted functional method of examining the prediction of gestational outcome. Key words: Doppler, umbilical artery, middle cerebral artery, uterine arteries

scholarly journals Dimerization and oligomerization of DNA-assembled building blocks for controlled multi-motion in high-order architectures

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Ling Xin ◽  
Xiaoyang Duan ◽  
Na Liu
Keyword(s):  
Building Block ◽  
Degrees Of Freedom ◽  
Building Blocks ◽  
Single Type ◽  
Hierarchical Assembly ◽  
Optical Responses ◽  
Self Association ◽  
Living Organisms ◽  
Order Structures ◽  
Chiral System

AbstractIn living organisms, proteins are organized prevalently through a self-association mechanism to form dimers and oligomers, which often confer new functions at the intermolecular interfaces. Despite the progress on DNA-assembled artificial systems, endeavors have been largely paid to achieve monomeric nanostructures that mimic motor proteins for a single type of motion. Here, we demonstrate a DNA-assembled building block with rotary and walking modules, which can introduce new motion through dimerization and oligomerization. The building block is a chiral system, comprising two interacting gold nanorods to perform rotation and walking, respectively. Through dimerization, two building blocks can form a dimer to yield coordinated sliding. Further oligomerization leads to higher-order structures, containing alternating rotation and sliding dimer interfaces to impose structural twisting. Our hierarchical assembly scheme offers a design blueprint to construct DNA-assembled advanced architectures with high degrees of freedom to tailor the optical responses and regulate multi-motion on the nanoscale.

scholarly journals Thermal Liquid Biopsy (TLB) Focused on Benign and Premalignant Pancreatic Cyst Diagnosis

2020 ◽  
Vol 11 (1) ◽  
pp. 25
Author(s):  
Sonia Hermoso-Durán ◽  
Guillermo García-Rayado ◽  
Laura Ceballos-Laita ◽  
Carlos Sostres ◽  
Sonia Vega ◽  
...  
Keyword(s):  
Liquid Biopsy ◽  
Pancreatic Cyst ◽  
Point Of View ◽  
Invasive Technique ◽  
Background Current ◽  
Interesting Point ◽  
Pancreatic Lesion ◽  
Non Invasive ◽  
Patient Diagnosis ◽  
New Biomarkers

Background: Current efforts in the identification of new biomarkers are directed towards an accurate differentiation between benign and premalignant cysts. Thermal Liquid Biopsy (TLB) has been previously applied to inflammatory and tumor diseases and could offer an interesting point of view in this type of pathology. Methods: In this work, twenty patients (12 males and 8 females, average ages 62) diagnosed with a pancreatic cyst benign (10) and premalignant (10) cyst lesions were recruited, and biological samples were obtained during the endoscopic ultrasonography procedure. Results: Proteomic content of cyst liquid samples was studied and several common proteins in the different groups were identified. TLB cyst liquid profiles reflected protein content. Also, TLB serum score was able to discriminate between healthy and cysts patients (71% sensitivity and 98% specificity) and between benign and premalignant cysts (75% sensitivity and 67% specificity). Conclusions: TLB analysis of plasmatic serum sample, a quick, simple and non-invasive technique that can be easily implemented, reports valuable information on the observed pancreatic lesion. These preliminary results set the basis for a larger study to refine TLB serum score and move closer to the clinical application of TLB providing useful information to the gastroenterologist during patient diagnosis.

Sign in / Sign up

Export Citation Format

Share Document