scholarly journals CMOS-Based Redox-Type Label-Free ATP Image Sensor for In Vitro Sensitive Imaging of Extracellular ATP

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 75
Author(s):  
Hideo Doi ◽  
Tomoko Horio ◽  
Yong-Joon Choi ◽  
Kazuhiro Takahashi ◽  
Toshihiko Noda ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Spatiotemporal Analysis ◽  
Image Sensor ◽  
Extracellular Atp ◽  
Nerve Tissue ◽  
Enzymatic Reactions ◽  
Label Free ◽  
Electron Mediator ◽  
Extracellular Signaling

Adenosine 5′-triphosphate (ATP) plays a crucial role as an extracellular signaling molecule in the central nervous system and is closely related to various nerve diseases. Therefore, label-free imaging of extracellular ATP dynamics and spatiotemporal analysis is crucial for understanding brain function. To decrease the limit of detection (LOD) of imaging extracellular ATP, we fabricated a redox-type label-free ATP image sensor by immobilizing glycerol-kinase (GK), L-α-glycerophosphate oxidase (LGOx), and horseradish peroxidase (HRP) enzymes in a polymer film on a gold electrode-modified potentiometric sensor array with a 37.3 µm-pitch. Hydrogen peroxide (H2O2) is generated through the enzymatic reactions from GK to LGOx in the presence of ATP and glycerol, and ATP can be detected as changes in its concentration using an electron mediator. Using this approach, the LOD for ATP was 2.8 µM with a sensitivity of 77 ± 3.8 mV/dec., under 10 mM working buffers at physiological pH, such as in in vitro experiments, and the LOD was great superior 100 times than that of the hydrogen ion detection-based image sensor. This redox-type ATP image sensor may be successfully applied for in vitro sensitive imaging of extracellular ATP dynamics in brain nerve tissue or cells.

scholarly journals Label-Free Split Aptamer Sensor for Femtomolar Detection of Dopamine by Means of Flexible Organic Electrochemical Transistors

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2577 ◽  
Author(s):  
Yuanying Liang ◽  
Ting Guo ◽  
Lei Zhou ◽  
Andreas Offenhäusser ◽  
Dirk Mayer
Keyword(s):  
Detection Limit ◽  
Electrochemical Sensors ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Label Free ◽  
Dopamine Detection ◽  
Electrochemical Transistor ◽  
Sensitivity And Selectivity

The detection of chemical messenger molecules, such as neurotransmitters in nervous systems, demands high sensitivity to measure small variations, selectivity to eliminate interferences from analogues, and compliant devices to be minimally invasive to soft tissue. Here, an organic electrochemical transistor (OECT) embedded in a flexible polyimide substrate is utilized as transducer to realize a highly sensitive dopamine aptasensor. A split aptamer is tethered to a gold gate electrode and the analyte binding can be detected optionally either via an amperometric or a potentiometric transducer principle. The amperometric sensor can detect dopamine with a limit of detection of 1 μM, while the novel flexible OECT-based biosensor exhibits an ultralow detection limit down to the concentration of 0.5 fM, which is lower than all previously reported electrochemical sensors for dopamine detection. The low detection limit can be attributed to the intrinsic amplification properties of OECTs. Furthermore, a significant response to dopamine inputs among interfering analogues hallmarks the selective detection capabilities of this sensor. The high sensitivity and selectivity, as well as the flexible properties of the OECT-based aptasensor, are promising features for their integration in neuronal probes for the in vitro or in vivo detection of neurochemical signals.

scholarly journals PfHRP2 detection using plasmonic optrodes: performance analysis

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Médéric Loyez ◽  
Mathilde Wells ◽  
Stéphanie Hambÿe ◽  
François Hubinon ◽  
Bertrand Blankert ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Limit Of Detection ◽  
Fiber Surface ◽  
Malaria Diagnosis ◽  
High Sensitivity ◽  
Cost Effective ◽  
Label Free ◽  
Multiple Receptors ◽  
Label Free Detection

Abstract Background Early malaria diagnosis and its profiling require the development of new sensing platforms enabling rapid and early analysis of parasites in blood or saliva, aside the widespread rapid diagnostic tests (RDTs). Methods This study shows the performance of a cost-effective optical fiber-based solution to target the presence of Plasmodium falciparum histidine-rich protein 2 (PfHRP2). Unclad multimode optical fiber probes are coated with a thin gold film to excite Surface Plasmon Resonance (SPR) yielding high sensitivity to bio-interactions between targets and bioreceptors grafted on the metal surface. Results Their performances are presented in laboratory conditions using PBS spiked with growing concentrations of purified target proteins and within in vitro cultures. Two probe configurations are studied through label-free detection and amplification using secondary antibodies to show the possibility to lower the intrisic limit of detection. Conclusions As malaria hits millions of people worldwide, the improvement and multiplexing of this optical fiber technique can be of great interest, especially for a future purpose of using multiple receptors on the fiber surface or several coated-nanoparticles as amplifiers.

scholarly journals Pipetting-based immunoassay for point-of-care testing: Application for detection of the influenza A virus

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Ji Yeong Noh ◽  
Sun-Woo Yoon ◽  
Youngji Kim ◽  
Thi Van Lo ◽  
Min-Ju Ahn ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Flow System ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Lateral Flow ◽  
Ease Of Use ◽  
Target Antigen ◽  
Enzymatic Reactions

Abstract Point-of-care tests (POCT) for pathogens are considered important for low-resource countries and facilities. Although lateral flow immunoassays (LFIA) have many advantages including speed and ease of use, their sensitivity is limited without specific equipment. Furthermore, their response cannot be enhanced through enzymatic reactions. Owing to these limitations, LFIAs have not yet been generally adopted as the standard protocol for in vitro analysis of infectious pathogens. We aimed to develop a novel pipetting-based immunoassay using a removable magnetic ring-coupled pipette tip. The “magnetic bead-capture antibody-targeted protein complex” was simply purified by pipetting and quantified by enzymatic colour development or using a lateral flow system. This pipetting-based immunoassay was applied to detect the nucleoprotein (NP) of the influenza A virus. Using an HRP-conjugated monoclonal antibody as a probe, the assay allowed for specific and sensitive detection. Furthermore, when this assay was applied exclusively for antigen capture in the lateral flow system, the limit of detection improved 100-fold and displayed greater sensitivity than the lateral flow system alone. Therefore, the pipetting-based immunoassay may be potentially used as a sensitive POCT to clinically detect a target antigen.

scholarly journals Porous Silicon-Based Aptasensors: The Next Generation of Label-Free Devices for Health Monitoring

Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2216 ◽  
Author(s):  
Monica Terracciano ◽  
Ilaria Rea ◽  
Nicola Borbone ◽  
Rosalba Moretta ◽  
Giorgia Oliviero ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Porous Silicon ◽  
Limit Of Detection ◽  
Combinatorial Libraries ◽  
High Sensitivity ◽  
Label Free ◽  
Great Specificity ◽  
Silicon Based ◽  
Exponential Enrichment

Aptamers are artificial nucleic acid ligands identified and obtained from combinatorial libraries of synthetic nucleic acids through the in vitro process SELEX (systematic evolution of ligands by exponential enrichment). Aptamers are able to bind an ample range of non-nucleic acid targets with great specificity and affinity. Devices based on aptamers as bio-recognition elements open up a new generation of biosensors called aptasensors. This review focuses on some recent achievements in the design of advanced label-free optical aptasensors using porous silicon (PSi) as a transducer surface for the detection of pathogenic microorganisms and diagnostic molecules with high sensitivity, reliability and low limit of detection (LoD).

scholarly journals Computational Design of a Molecularly Imprinted Polymer for the Biomonitoring of the Organophosphorous Metabolite Chlorferron

Biosensors ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 192
Author(s):  
Bakhtiyar Qader ◽  
Issam Hussain ◽  
Mark Baron ◽  
Rebeca Jiménez-Pérez ◽  
Guzmán Gil-Ramírez ◽  
...  
Keyword(s):  
Biological Samples ◽  
Limit Of Detection ◽  
Computational Design ◽  
Signal Change ◽  
Highly Sensitive ◽  
Limit Of Quantitation ◽  
Molecularly Imprinting Polymers ◽  
Mip Sensor ◽  
Parasitic Mites

Coumaphos is an organophosphorus compound used as insecticide and frequently used by beekeepers for the management of parasitic mites. The most important metabolite, chlorferron (CFN), has been identified in biological samples and foodstuff. The need to quickly identify the presence of typical metabolites, as an indication of interaction with coumaphos has driven the need to produce a highly sensitive electrochemical method for chlorferron analysis, based on molecularly imprinting polymers (MIP) technology. It showed irreversible behaviour with mixed diffusion/adsorption-controlled reactions at the electrode surface. A monoelectronic mechanism of reaction for oxidation has also been suggested. The linear range observed was from 0.158 to 75 µM. Median precision in terms of %RSD around 3% was also observed. For DPV, the limit of detection (LOD) and the limit of quantitation (LOQ) for the CFN-MIP were 0.158 µM and 0.48 µM, respectively. The obtained median % recovery was around 98%. The results were also validated to reference values obtained using GC-MS. Urine and human synthetic plasma spiked with CFN were used to demonstrate the usability of the method in biological samples, showing the potential for biomonitoring. The developed imprinted sensor showed maximum signal change less than 16.8% when related metabolites or pesticide were added to the mix, suggesting high selectivity of the MIP sensor toward CFN molecules. The results from in vitro metabolism of CMP analysed also demonstrates the potential for detection and quantification of CFN in environmental samples. The newly developed CFN-MIP sensor offers similar LoDs than chromatographic methods with shorter analysis time.

scholarly journals Demonstration of a Label-Free and Low-Cost Optical Cavity-Based Biosensor Using Streptavidin and C-Reactive Protein

Biosensors ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Donggee Rho ◽  
Seunghyun Kim
Keyword(s):  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Optical Cavity ◽  
Sample Volume ◽  
Small Sample ◽  
Label Free ◽  
C Reactive Protein ◽  
Reactive Protein ◽  
Cavity Structure

An optical cavity-based biosensor (OCB) has been developed for point-of-care (POC) applications. This label-free biosensor employs low-cost components and simple fabrication processes to lower the overall cost while achieving high sensitivity using a differential detection method. To experimentally demonstrate its limit of detection (LOD), we conducted biosensing experiments with streptavidin and C-reactive protein (CRP). The optical cavity structure was optimized further for better sensitivity and easier fluid control. We utilized the polymer swelling property to fine-tune the optical cavity width, which significantly improved the success rate to produce measurable samples. Four different concentrations of streptavidin were tested in triplicate, and the LOD of the OCB was determined to be 1.35 nM. The OCB also successfully detected three different concentrations of human CRP using biotinylated CRP antibody. The LOD for CRP detection was 377 pM. All measurements were done using a small sample volume of 15 µL within 30 min. By reducing the sensing area, improving the functionalization and passivation processes, and increasing the sample volume, the LOD of the OCB are estimated to be reduced further to the femto-molar range. Overall, the demonstrated capability of the OCB in the present work shows great potential to be used as a promising POC biosensor.

scholarly journals The signaling role of extracellular ATP in co-culture of Shiraia sp. S9 and Pseudomonas fulva SB1 for enhancing hypocrellin A production

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Xin Ping Li ◽  
Lu Lu Zhou ◽  
Yan Hua Guo ◽  
Jian Wen Wang
Keyword(s):  
Atp Release ◽  
Specific Inhibitor ◽  
Extracellular Atp ◽  
Oxidase Inhibitor ◽  
Disulfonic Acid ◽  
Early Event ◽  
Fungal Metabolites ◽  
Extracellular Signaling ◽  
Hypocrellin A

Abstract Background Adenosine 5′-triphosphate (ATP) plays both a central role as an intracellular energy source, and a crucial extracellular signaling role in diverse physiological processes of animals and plants. However, there are less reports concerning the signaling role of microbial extracellular ATP (eATP). Hypocrellins are effective anticancer photodynamic therapy (PDT) agents from bambusicolous Shiraia fungi. The co-culture of Shiraia sp. S9 and a bacterium Pseudomonas fulva SB1 isolated from Shiraia fruiting bodies was established for enhanced hypocrellin A (HA) production. The signaling roles of eATP to mediate hypocrellin biosynthesis were investigated in the co-culture. Results The co-culture induced release of eATP at 378 nM to the medium around 4 h. The eATP release was interdependent on cytosolic Ca2+ concentration and reactive oxygen species (ROS) production, respectively. The eATP production could be suppressed by the Ca2+ chelator EGTA or abolished by the channel blocker La3+, ROS scavenger vitamin C and NADPH oxidase inhibitor diphenyleneiodonium chloride (DPI). The bacterium-induced H2O2 production was strongly inhibited by reactive blue (RB), a specific inhibitor of membrane purinoceptors, but dependent on the induced Ca2+ influx in the co-culture. On the other hand, the application of exogenous ATP (exATP) at 10–300 µM to Shiraia cultures also promoted fungal conidiation and HA production, both of which were blocked effectively by the purinoceptor inhibitors pyridoxalphosphate-6-azophenyl-2′, 4′-disulfonic acid (PPADS) and RB, and ATP hydrolase apyrase. Both the induced expression of HA biosynthetic genes and HA accumulation were inhibited significantly under the blocking of the eATP or Ca2+ signaling, and the scavenge of ROS in the co-culture. Conclusions Our results indicate that eATP release is an early event during the intimate bacterial–fungal interaction and eATP plays a signaling role in the bacterial elicitation on fungal metabolites. Ca2+ and ROS are closely linked for activation of the induced ATP release and its signal transduction. This is the first report on eATP production in the fungal–bacterial co-culture and its involvement in the induced biosynthesis of fungal metabolites. Graphic abstract

Intracellular signaling molecules of nerve tissue progenitors as pharmacological targets for treatment of ethanol-induced neurodegeneration

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Gleb Nikolaevich Zyuz’kov ◽  
Larisa Arkad`evna Miroshnichenko ◽  
Elena Vladislavovna Simanina ◽  
Larisa Alexandrovna Stavrova ◽  
Tatyana Yur`evna Polykova
Keyword(s):  
Stem Cells ◽  
Alcohol Abuse ◽  
Intracellular Signaling ◽  
Signaling Molecules ◽  
Growth Potential ◽  
Nerve Tissue ◽  
Intracellular Signaling Molecules

Abstract Objectives The development of approaches to the treatment of neurodegenerative diseases caused by alcohol abuse by targeted pharmacological regulation of intracellular signaling transduction of progenitor cells of nerve tissue is promising. We studied peculiarities of participation of NF-кB-, сАМР/РКА-, JAKs/STAT3-, ERK1/2-, p38-pathways in the regulation of neural stem cells (NSC) and neuronal-committed progenitors (NCP) in the simulation of ethanol-induced neurodegeneration in vitro and in vivo. Methods In vitro, the role of signaling molecules (NF-кB, сАМР, РКА, JAKs, STAT3, ERK1/2, p38) in realizing the growth potential of neural stem cells (NSC) and neuronal-committed progenitors (NCP) in ethanol-induced neurodegeneration modeled in vitro and in vivo was studied. To do this, the method of the pharmacological blockade with the use of selective inhibitors of individual signaling molecules was used. Results Several of fundamental differences in the role of certain intracellular signaling molecules (SM) in proliferation and specialization of NSC and NCP have been revealed. It has been shown that the effect of ethanol on progenitors is accompanied by the formation of a qualitatively new pattern of signaling pathways. Data have been obtained on the possibility of stimulation of nerve tissue regeneration in ethanol-induced neurodegeneration by NF-кB and STAT3 inhibitors. It has been found that the blockage of these SM stimulates NSC and NCP in conditions of ethanol intoxication and does not have a «negative» effect on the realization of the growth potential of intact progenitors (which will appear de novo during therapy). Conclusions The results may serve as a basis for the development of fundamentally new drugs to the treatment of alcoholic encephalopathy and other diseases of the central nervous system associated with alcohol abuse.

scholarly journals Anemoside B4 ameliorates TNBS-induced colitis through S100A9/MAPK/NF-κB signaling pathway

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yong Zhang ◽  
Zhengxia Zha ◽  
Wenhua Shen ◽  
Dan Li ◽  
Naixin Kang ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Signaling Pathway ◽  
Tca Cycle ◽  
Mapk Signaling ◽  
Enzyme Linked Immunosorbent Assay ◽  
Trinitrobenzene Sulfonic Acid ◽  
Therapeutic Effects ◽  
Triterpenoid Saponin ◽  
Label Free

Abstract Background Despite the increased morbidity of ulcerative colitis (UC) in the developing countries, available treatments remain unsatisfactory. Therefore, it is urgent to discover more effective therapeutic strategies. Pulsatilla chinensis was widely used for the treatment of inflamed intestinal diseases including UC for thousands of years in China. Anemoside B4, the most abundant triterpenoid saponin isolated from P. chinensis, exerts anti-inflammatory and antioxidant effects and may be the most active compounds, which is responsible for the therapeutic effects. However, the mechanism how anemoside B4 executes its biological functions is still elusive. Methods Here, we used the 2, 4, 6-trinitrobenzene sulfonic acid (TNBS)-induced colitis rat model to evaluate the therapeutic effect of anemoside B4. Blood samples of colitis rats were collected for hematology analysis. The inflammation-associated factors were investigated by enzyme-linked immunosorbent assay (ELISA). Cell proliferation and apoptosis was determined with EdU cell proliferation assay and TUNEL assay. The proteins regulated by anemoside B4 were identified by label-free quantitative proteomics. The significantly down-regulated proteins were verified by Western blotting analysis. mRNA expression was analyzed by quantitative real-time RT-PCR. Results The results showed that anemoside B4 ameliorated TNBS-induced colitis symptoms, including tissue damage, inflammatory cell infiltration, and pro-inflammatory cytokine production, apoptosis and slowed proliferation in colon. Quantitative proteomic analyses discovered that 56 proteins were significantly altered by anemoside B4 in the TNBS-induced rats. These proteins mainly clustered in tricarboxylic acid (TCA) cycle and respiratory electron transport chain. Among the altered proteins, S100A9 is one of the most significantly down-regulated proteins and associated with NF-κB and MAPK signaling pathways in the pathogenesis of UC. Further experiments revealed that anemoside B4 suppressed the expression of S100A9 and its downstream genes including TLR4 and NF-κB in colon. In vitro, anemoside B4 could inhibit the NF-κB signaling pathway induced by recombinant S100A9 protein in human intestinal epithelial Caco-2 cells. Moreover, anemoside B4 inhibits neutrophils recruitment and activation in colon induced by TNBS. Conclusions Our results demonstrate that anemoside B4 prevents TNBS-induced colitis by inhibiting the NF-κB signaling pathway through deactivating S100A9, suggesting that anemoside B4 is a promising therapeutic candidate for colitis.

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