scholarly journals Trace impurities in test stimuli can seriously compromise chemosensory studies

2018 ◽  
Author(s):  
Dirk Louis P. Schorkopf ◽  
Bela Peter Molnar ◽  
Marit Solum ◽  
Mattias C. Larsson ◽  
Jocelyn G. Millar ◽  
...  
Keyword(s):  
Degradation Products ◽  
Olfactory Receptors ◽  
High Sensitivity ◽  
Check Sample ◽  
Trace Impurities ◽  
Receptor Ligand ◽  
Technological Advances ◽  
Common Fatty Acid ◽  
Main Component ◽  
Volatile Impurities

The discovery of olfactory receptors and major technological advances have greatly accelerated our understanding of chemosensory mechanisms. However, some of this rapid progress may be compromised by inadequate knowledge or characterization of the purity of chemical stimuli used to challenge olfactory or other chemoreceptors when mapping their response profiles. Here, we provide strong evidence that the presence of trace impurities in test stimuli can completely obscure true ligand-receptor relationships. DmOR7a, an olfactory receptor of the vinegar fly (Drosophila melanogaster) has been reported to respond to several long-chain aliphatic ligands such as a putative Drosophila pheromone, the pheromone of the silkworm moth Bombyx mori, and a common fatty acid, linoleic acid. By contrast, we show that DmOR7a responds with high sensitivity to volatile impurities and degradation products present in minute quantities in authentic standards of those compounds, but not to the standards themselves. Responses to impurities can easily go unnoticed due to two main factors. First, the sensitivity of receptors to key ligands may be greater than that of analytical chemistry instruments used to check sample purity. Second, the concentration of highly volatile impurities in an odour puff may be orders of magnitude higher than the main component of a sample, due to the large differences in vapour pressures between the impurities and the main component. Issues concerning impurities are not limited to studies on olfaction that use odour puffs to characterize receptor-ligand interactions, but may affect all studies on chemosensation, from molecular biology and in-silico predictions to behaviour. Purity, which is crucial in receptor-ligand studies, is always implied, but rarely checked rigorously. To avoid misinterpretations, a proper account of all compounds present in test stimuli and an unequivocal confirmation of ligand affinity should accompany chemosensory studies.

scholarly journals Wearable Pressure Sensors Based on Carbonized Graphene Coated Waste Paper Aerogel

2021 ◽  
Author(s):  
Ang Li ◽  
Ce Cui ◽  
Weijie Wang ◽  
Yue Zhang ◽  
Jianyu Zhai ◽  
...  
Keyword(s):  
3D Structure ◽  
Pressure Sensors ◽  
High Sensitivity ◽  
Waste Paper ◽  
Low Density ◽  
Detection Range ◽  
Simple Strategy ◽  
Simple Filtration ◽  
Piezoresistive Pressure Sensors ◽  
Main Component

Abstract Graphene is complexed with cellulose fibers to construct 3D aerogels, which is generally considered to be an environmentally friendly and simple strategy to achieve wide sensing, high sensitivity and low detection of wearable piezoresistive pressure sensors. Here, graphene is incorporated into waste paper fibers with cellulose as the main component to prepare graphene coated waste paper aerogel (GWA) using a simple “filtration-oven drying” method under atmospheric pressure. The GWA was further annealed to obtain the carbonized graphene coated waste paper aerogel (C-GWA) to achieve low density and excellent resilience. The result shows that the C-GWA has a rough outer surface due to the 3D structure formed by interpenetrated fibers and the carbon skeleton with wrinkles. The sensor based on GCA shows low density (25mg/cm3), a wide detection range of 0-132 kPa, an ultra-low detection limit of 2.5 Pa (a green bean, ≈ 53.4 mg), and a high sensitivity of 31.6 kPa− 1. In addition, the sensor based on C-GWA with the excellent performance can be used to detect human motions including the pulse of the human body, cheek blowing and bending of human joints. The result indicates that the sensor based on C-GWA shows great potential for wearable electronic products.

scholarly journals High-Performance Thin-Layer Chromatography with Densitometry for the Determination of Ciprofloxacin and Impurities in Drugs

2005 ◽  
Vol 88 (5) ◽  
pp. 1530-1536 ◽  
Author(s):  
Jan Krzek ◽  
Urszula Hubicka ◽  
Justyna Szczepańczyk
Keyword(s):  
Thin Layer ◽  
High Performance ◽  
Limit Of Detection ◽  
Degradation Products ◽  
Pharmaceutical Preparations ◽  
High Sensitivity ◽  
Good Precision ◽  
Relative Standard ◽  
Tlc Plates ◽  
Quantitative Analyses

Abstract A thin-layer chromatographic (TLC)-densitometric method has been developed for identification and quantification of ciprofloxacin (Rf = 0.61) and an ethylenediamine compound (Rf = 0.42), a desfluoro compound (Rf = 0.48), by-compound A (Rf = 0.53), and fluoroquinolonic acid (Rf = 0.68) as ciprofloxacin degradation products in pharmaceutical preparations. By using chloroform–methanol–25% ammonia (43 + 43 + 14, v/v/v) as the mobile phase and silica gel 60 F254 high-performance TLC plates as the stationary phase, it was possible to separate individual constituents that, when subjected to ultraviolet (UV) densitometric analysis at 330 nm for fluoroquinolonic acid and 277 nm for the other compounds, gave well developed peaks allowing easy qualitative and quantitative analyses. DMSO–methanol (1 + 1) was used to extract drug constituents. The method showed high sensitivity (limit of detection 10 to 44 ng), a wide linearity range (3 to 20 μg/mL), and good precision (2.32 to 6.46% relative standard deviation) and accuracy (percentage recoveries 98.62 to 101.52%) for individual constituents.

DEVELOPMENT OF A NEW ASSAY METHOD FOR THE DETECTION OF DD/E COMPLEX

1987 ◽  
Author(s):  
K KUROSO ◽  
S IKEMATSU ◽  
M HADA ◽  
M FUJIMAKI ◽  
K FUKUTAKE
Keyword(s):  
Degradation Products ◽  
Early Stage ◽  
High Sensitivity ◽  
Assay Method ◽  
Quantitative Detection ◽  
Horse Radish Peroxidase ◽  
Microtitre Plate ◽  
Antibody Technique ◽  
Anti Body ◽  
D Dimer

A new assay method for the detection of DD/E complex derived from crosslinked fibrin is developed. This assay is performed on a microtitre plate using capture/tag antibody technique, in which the monoclonal antibody against D dimer fragment (DD-3B6, MAbCO) is coated and anti-E fragment polyclonal F(ab)’2 conjugated with horse radish peroxidase is for a tag-anti body. Antigen dilution curve is drawn in the range of 0.01-1.0 pg/ml of purified DD/E complex. DD/E complex can be measured specifically and other high molecular weight derivatives from crosslinked fibrin show a little crossreaction, though fibrinogen and fibrinogen degradation products show no crossreactivities on this assay. D dimer fragment dissociated from DD/E complex after further plasmin digestion is less reactive in this assay, while this type of D dimer can be detected by DIMERTEST-EIA (MAbCO). These data suggest that an early stage of plasmin digestion of crosslinked fibrin can be detected by this method. A trace amount of DD/E complex curculating in plasma from a small thrombus is possibly detected, because this assay gives an excellent high sensitivity with the detection limit of 0.01 jug/ ml. Normal value of plasma DD/E complex (n=50) indicates below 0.12 pg/ml as 90 percentile. Patients with DIC (n=24) show high levels of DD/E complex between 0.6 and 40 g/ml. These elevated levels of DD/E complex may suggest consequently the existence of the plasmic digestion of crosslinked fibrin in the cases with DIC. In summary, it is concluded that the development of this assay will add one technique to discriminate between fibrinolysis and fibrinogenolysis and this assay is useful for the quantitative detection of DD/E complex produced in an early stage of fibrinolysis seen in various thrombotic disorders, and for the evaluation of the efficacy of thrombolytic therapy.

scholarly journals THE IMPORTANCE OF THROMBOELASTOMETRY IN THE HEMOSTATIC DISORDERS DIAGNOSIS IN INTENCIVE CARE PATIENTS WITH TRAUMAS (CLINICAL CASE)

2021 ◽  
Vol 1 (5(69)) ◽  
pp. 38-45
Author(s):  
O. Kostrova ◽  
I. Stomenskaya ◽  
N. Timofeeva ◽  
N. Buryachenko ◽  
I. Cherkasov ◽  
...  
Keyword(s):  
Degradation Products ◽  
High Sensitivity ◽  
Fold Increase ◽  
Traumatic Shock ◽  
Normal Limits ◽  
Fibrin Degradation Products ◽  
Craniocerebral Injuries ◽  
Angle Alpha ◽  
Male Patients ◽  
Hemostatic Disorders

thromboelastometry and coagulogram in patients with polytrauma. Materials and methods. The results of thromboelastometry (TEM) and standard coagulogram of 12 patients aged 18 to 74 years with a diagnosis of trauma were analyzed. Analysis of thromboelastometry was performed using a ROTEM delta blood analyzer (Tem Innovations GmbH, Germany), which evaluates the physical properties of a clot. Patients' blood stabilized with sodium citrate was placed in special disposable microcuvettes with the addition of various activators of coagulation reactions. The following indicators of thromboelastometry were determined: CT, CFT, angle alpha (α), MCF, A5, A10 in the tests INTEM, EXTEM and FIBTEM. The determination of coagulogram parameters was carried out according to a standard method. The following parameters were identified: APTT, INR, fibrinogen A content, serum fibrin degradation products (SFDP) concentration. Results. Coagulogram and thromboelastometry data at different stages of treatment were compared. In patients with the development of traumatic shock, coagulogram indices were changed to varying degrees depending on the stage of a shock. At the first stage of shock, the analysis showed only a 2-fold increase in SFDP and a slight increase in fibrinogen in dynamics. In a patient with a third stage of traumatic shock, the coagulogram indices were within normal limits, but according to TEM (EXTEM and FIBTEM tests), hypocoagulation was observed due to platelets. Only a coagulogram was evaluated in dynamics, hypocoagulation was observed in parameters of internal and external hemostasis pathways (prolongation of APTT, decrease in IPT and increase in INR), increase in fibrinogen A and SFDP. In the group of male patients with closed craniocerebral injuries, an increase in SFMC in the coagulogram had always been combined with changes in the FIBTEM test during TEM. Conclusion. Thus, in most patients, there is no change in classic coagulogram tests immediately after the injury. At the same time, rotational thromboelastometry makes it possible to fill this deficiency at an earlier date, which indicates a high sensitivity of the method.

scholarly journals Odorant Binding Changes the Electrical Properties of Olfactory Receptors at the Nanoscale

2021 ◽  
Author(s):  
Anna Lagunas ◽  
Christine Belloir ◽  
Loic Briand ◽  
Pau Gorostiza ◽  
Josep Samitier
Keyword(s):  
Electrical Properties ◽  
Electrical Characterization ◽  
Olfactory Receptors ◽  
High Sensitivity ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Sensitivity And Selectivity ◽  
Fixed Orientation ◽  
Impedance Parameters ◽  
Odorant Binding

The transduction of odorant binding into cellular signaling by olfactory receptors (ORs) is not understood and knowing its mechanism would enable developing new pharmacology and biohybrid electronic detectors of volatile organic com-pounds bearing high sensitivity and selectivity. The electrical characterization of ORs in bulk experiments is subject to microscopic models and assumptions. We have directly determined the nanoscale electrical properties of ORs immobilized in a fixed orientation, and their change upon odorant binding, using electrochemical scanning tunneling microscopy (EC-STM) in near-physiological conditions. Recordings of current versus time, distance, and electrochemical potential allows determining the OR impedance parameters and their dependence with odorant binding. Our results allow validating OR structural-electrostatic models and their functional activation processes.

scholarly journals Ionic contrast across a lipid membrane for Debye length extension: towards an ultimate bioelectronics transducer

2020 ◽  
Author(s):  
Donggeun Lee ◽  
Suho Lee ◽  
Eui-Sang Yu ◽  
Taikjin Lee ◽  
Jae Hun Kim ◽  
...  
Keyword(s):  
Lipid Membrane ◽  
Field Effect Transistors ◽  
Debye Length ◽  
Free Water ◽  
Water Layer ◽  
Underlying Mechanism ◽  
High Energy ◽  
Receptor Ligand ◽  
Technological Advances ◽  
Ionic Contrast

Abstract Despite technological advances in biomolecule detections, evaluation of molecular interactions via potentiometric devices under ion-enriched solutions has remained a long-standing problem. To avoid severe performance degradation of bioelectronics by ionic screening effects, we cover probe surfaces of field effect transistors (FETs) with a single film of the supported lipid bilayer (SLB), and realize outstanding potentiometric signals from receptor-ligand bindings irrespective of ionic strength of bulky solutions by placing an ion-free water layer underneath the SLB. High-energy X-ray reflectometry together with the circuit analysis discovered biochemical findings that effective electrical signals dominantly originated from the sub-nanoscale conformational change of lipids in the course of receptor-ligand bindings. Beyond thorough analysis on the underlying mechanism at the molecular level, the proposed SLB-FET platform ensures the world-record level of sensitivity in molecular detection with excellent reproducibility regardless of molecular charges and environmental ionic conditions.

scholarly journals Emerging Optical Materials in Sensing and Discovery of Bioactive Compounds

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5784
Author(s):  
Raquel Vaz ◽  
Beatriz Valpradinhos ◽  
Manuela F. Frasco ◽  
Maria Goreti F. Sales
Keyword(s):  
Drug Discovery ◽  
Bioactive Compounds ◽  
High Throughput Screening ◽  
High Sensitivity ◽  
Optical Biosensors ◽  
Chemical Compositions ◽  
Bioactive Natural Products ◽  
Real Time Analysis ◽  
Technological Advances ◽  
Recent Developments

Optical biosensors are used in numerous applications and analytical fields. Advances in these sensor platforms offer high sensitivity, selectivity, miniaturization, and real-time analysis, among many other advantages. Research into bioactive natural products serves both to protect against potentially dangerous toxic compounds and to promote pharmacological innovation in drug discovery, as these compounds have unique chemical compositions that may be characterized by greater safety and efficacy. However, conventional methods for detecting these biomolecules have drawbacks, as they are time-consuming and expensive. As an alternative, optical biosensors offer a faster, simpler, and less expensive means of detecting various biomolecules of clinical interest. In this review, an overview of recent developments in optical biosensors for the detection and monitoring of aquatic biotoxins to prevent public health risks is first provided. In addition, the advantages and applicability of these biosensors in the field of drug discovery, including high-throughput screening, are discussed. The contribution of the investigated technological advances in the timely and sensitive detection of biotoxins while deciphering the pathways to discover bioactive compounds with great health-promoting prospects is envisaged to meet the increasing demands of healthcare systems.

scholarly journals Evaluation of Three Peptide Immobilization Techniques on a QCM Surface Related to Acetaldehyde Responses in the Gas Phase

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3942 ◽  
Author(s):  
Tomasz Wasilewski ◽  
Bartosz Szulczyński ◽  
Wojciech Kamysz ◽  
Jacek Gębicki ◽  
Jacek Namieśnik
Keyword(s):  
Spin Coating ◽  
Olfactory Receptors ◽  
High Sensitivity ◽  
Dip Coating ◽  
Label Free ◽  
Optimal Method ◽  
Spin Coating Method ◽  
Whole Cells ◽  
Label Free Detection ◽  
Coating Method

The quartz-crystal microbalance is a sensitive and universal tool for measuring concentrations of various gases in the air. Biochemical functionalization of the QCM electrode allows a label-free detection of specific molecular interactions with high sensitivity and specificity. In addition, it enables a real-time determination of its kinetic rates and affinity constants. This makes QCM a versatile bioanalytical screening tool for various applications, with surface modifications ranging from the detection of single molecular monolayers to whole cells. Various types of biomaterials, including peptides mapping the binding sites of olfactory receptors, can be deposited as a sensitive element on the surface of the electrodes. One of key ways to ensure the sensitivity and accuracy of the sensor is provided by application of an optimal and repeatable method of immobilization. Therefore, effective sensors operation requires development of an optimal method of deposition. This paper reviews popular techniques (drop-casting, spin-coating, dip-coating) for coating peptides on piezoelectric crystals surface. Peptide (LEKKKKDC-NH2) derived from an aldehyde binding site in the HarmOBP7 protein was synthesized and used as a sensing material for the biosensor. The degree of deposition of the sensitive layer was monitoring by variations in the sensors frequency. The highest mass threshold for QCM measurements for peptides was approximately 16.43 µg·mm−2 for spin coating method. Developed sensor exhibited repeatable response to acetaldehyde. Moreover, responses to toluene was observed to evaluate sensors specificity. Calibration curves of the three sensors showed good determination coefficients (R2 > 0.99) for drop casting and dip coating and 0.97 for the spin-coating method. Sensors sensitivity vs. acetaldehyde were significantly higher for the dip-coating and drop-casting methods and lower for spin-coating one.

Cellulase Enzyme based Biodegradation of Cellulosic Materials: An Overview

2016 ◽  
Vol 5 (6) ◽  
pp. 271-282
Author(s):  
Soumya Chatterjee ◽  
Sonika Sharma ◽  
Rajesh Kumar Prasad ◽  
Sibnarayan Datta ◽  
Dharmendra Dubey ◽  
...  
Keyword(s):  
Plant Biomass ◽  
Raw Materials ◽  
Insect Pest ◽  
Biofuel Production ◽  
Anthropogenic Sources ◽  
Organic Polymer ◽  
Cellulase Enzymes ◽  
Technological Advances ◽  
Insect Gut ◽  
Main Component

Cellulose, a macromolecule of β -D- anhydroglucopyranose units linked by β (1,4)-glycosidic bonds, is the world’s most abundant organic polymer and is the main component of plant biomass that provides stability. Due to its sta-ble fibrous property, it has become one of the most important commercial raw materials for many industries. However, accumulation of waste cellulose due to natural and/or anthropogenic sources is a matter of concern in terms of environmental pollution. Wastes cellulosic substrates can be utilized as sources of energy through controlled hydrolysis using cellulases- a complex group of enzymes capable of degrading all types of cellulosic waste materials. A number of bacteria, fungi and insects are having the capability to degrade cellulose by production of cellulase enzymes. Further, the symbiotic insect-microbe relationships present in the insect gut microbiome for the production of cellulolytic system is of immense importance as this would lead to applications in different fields like biodegradation of cellulosic wastes, pollution reduction, biofuel production, insect/pest control etc. Cel-lulase gene can also be improved by genetic or protein engineering methods using recent technological advances. This review deals with the advances of cellulase enzymes and its utilization for different application.

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