scholarly journals Enhanced Colorimetric Signal for Accurate Signal Detection in Paper-Based Biosensors

Diagnostics ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 28 ◽  
Author(s):  
Dorin Harpaz ◽  
Evgeni Eltzov ◽  
Timothy S. E. Ng ◽  
Robert S. Marks ◽  
Alfred I. Y. Tok
Keyword(s):  
Signal Detection ◽  
Signal Amplification ◽  
Sulfonic Acid ◽  
Color Intensity ◽  
Pvdf Membrane ◽  
Polyvinylidene Difluoride ◽  
Signal Color ◽  
Stable Signal ◽  
Amplification Procedure ◽  
Colorimetric Reaction

Paper-based colorimetric biosensors combine the use of paper with colorimetric signal detection. However, they usually demonstrate lower sensitivities because a signal amplification procedure has not been used. Stopping the reaction of colorimetric signal generation is often used in lab-based assays in order to amplify and stabilize the colorimetric signal for detection. In this study, the generation of a stopped colorimetric signal was examined for accurate and enhanced signal detection in paper-based biosensors. The colorimetric reaction in biosensors is usually based on the interaction between the enzyme horseradish peroxidase (HRP) and a selected chromogenic substrate. The two most commonly used HRP substrates, 3,3’,5,5’-tetramethylbenzidine (TMB) and 2’-azinobis (3-ethylbenzothiazoline-6-sulfonic-acid) (ABTS), were compared in terms of their ability to generate a stopped colorimetric signal on membrane. The stopped colorimetric signal was visible for TMB but not for ABTS. Moreover, the generation of stopped colorimetric signal was dependent on the presence of polyvinylidene-difluoride (PVDF) membrane as the separation layer. With PVDF the colorimetric signal (color intensity) was higher (TMB: 126 ± 6 and ABTS: 121 ± 9) in comparison to without PVDF (TMB: 110 ± 2 and ABTS: 102 ± 4). The TMB stopped colorimetric signal demonstrated a more stable signal detection with lower standard deviation values. To conclude, a stopped colorimetric signal can be generated in paper-based biosensors for enhanced and accurate signal detection.

scholarly journals Synthesis, characterization and filtration performance of the polyvinylidene fluoride membrane modified by poly(methyl ethacrylate-co-2-acrylamido-2-methylpropane sulfonic acid)

2018 ◽  
Vol 19 (4) ◽  
pp. 1279-1285
Author(s):  
Q. Y. Zhang ◽  
Q. An ◽  
Y. G. Guo ◽  
J. Zhang ◽  
K. Y. Zhao
Keyword(s):  
Sulfonic Acid ◽  
Polyvinylidene Fluoride ◽  
Phase Inversion ◽  
Pure Water ◽  
Water Flux ◽  
Contact Angles ◽  
Fouling Resistance ◽  
Inversion Process ◽  
Pvdf Membrane ◽  
Pure Water Flux

Abstract To enhance the anti-fouling and separating properties of polyvinylidene fluoride (PVDF) membranes, an amphiphilic copolymer of methyl methacrylate and 2-acrylamido-2-methylpropane sulfonic acid, poly(MMA-co-AMPS), was designed and synthesized. Through a phase-inversion process, the poly(MMA-co-AMPS) were fully dispersed in the PVDF membrane. The properties of membrane including the surface and cross-section morphology, surface wettability and fouling resistance under different pH solutions were investigated. Compared to the unmodified PVDF membranes, the contact angles of modified PVDF membranes decreased from 80.6° to 71.6°, and the pure water flux increased from 54 to 71 L·m−2·h−1. In addition, the hybrid PVDF membrane containing 0.5 wt% copolymers demonstrated an larger permeability, better fouling resistance and higher recovery ratio via pure water backlashing, when it was compared with the other blend membranes, and the virgin one in the cyclic test of anti-fouling. The modified membranes with the copolymers possessed an outstanding performance and may be used for further water treatment applications.

Structure and Morphology of PVDF-G-PAMPS Membrane

2011 ◽  
Vol 197-198 ◽  
pp. 1321-1324 ◽  
Author(s):  
Gui Bao Guo ◽  
Sheng Li An
Keyword(s):  
Fourier Transform ◽  
Infrared Spectroscopy ◽  
Sulfonic Acid ◽  
Proton Exchange Membrane ◽  
Vinylidene Fluoride ◽  
Proton Exchange ◽  
Pvdf Membrane ◽  
Structure And Morphology ◽  
Poly Vinylidene Fluoride ◽  
Exchange Membrane

A proton exchange membrane of blended poly (acrylamido-2- methylpropane sulfonic acid) (PAMPS) grafted onto modified poly (vinylidene fluoride) (PVDF) membrane (PVDF-g-PAMPS) was prepared. Fourier transform infrared spectroscopy is used to characterize changes of the membrane's microstructures after grafting. The morphology of the membrane's microstructures after grafting is studied by scanning electrolytic microscope.The results show that 2-acrylamido-2-methylpropane sulfonic acid is easily grafted into PVDF modified by Plain sodium silicate (Na4SiO4).

scholarly journals Zwitterionic Polymer Brush Grafted on Polyvinylidene Difluoride Membrane Promoting Enhanced Ultrafiltration Performance with Augmented Antifouling Property

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1303 ◽  
Author(s):  
Yu-Hsuan Chiao ◽  
Shu-Ting Chen ◽  
Mani Sivakumar ◽  
Micah Belle Marie Yap Ang ◽  
Tanmoy Patra ◽  
...  
Keyword(s):  
Uv Light ◽  
Membrane Surface ◽  
Polymer Brush ◽  
Dynamic Test ◽  
Time Interval ◽  
Pvdf Membrane ◽  
Polyvinylidene Difluoride ◽  
Time Control ◽  
Zwitterionic Polymer ◽  
Analytical Tools

Superhydrophilic zwitterions on the membrane surface have been widely exploited to improve antifouling properties. However, the problematic formation of a <20 nm zwitterionic layer on the hydrophilic surface remains a challenge in wastewater treatment. In this work, we focused on the energy consumption and time control of polymerization and improved the strong hydrophilicity of the modified polyvinylidene difluoride (PVDF) membrane. The sulfobetaine methacrylate (SBMA) monomer was treated with UV-light through polymerization on the PVDF membrane at a variable time interval of 30 to 300 s to grow a poly-SBMA (PSBMA) chain and improve the membrane hydrophilicity. We examined the physiochemical properties of as-prepared PVDF and PVDF–PSBMAx using numeric analytical tools. Then, the zwitterionic polymer with controlled performance was grafted onto the SBMA through UV-light treatment to improve its antifouling properties. The PVDF–PSBMA120s modified membrane exhibited a greater flux rate and indicated bovine serum albumin (BSA) rejection performance. PVDF–PSBMA120s and unmodified PVDF membranes were examined for their antifouling performance using up to three cycles dynamic test using BSA as foulant. The PVDF-modified PSBMA polymer improved the antifouling properties in this experiment. Overall, the resulting membrane demonstrated an enhancement in the hydrophilicity and permeability of the membrane and simultaneously augmented its antifouling properties.

scholarly journals Fabrication of Polyvinylidene Difluoride Membrane with Enhanced Pore and Filtration Properties by Using Tannic Acid as an Additive

Polymers ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 186
Author(s):  
Sri Mulyati ◽  
Sri Aprilia ◽  
Syawaliah Muchtar ◽  
Yanna Syamsuddin ◽  
Cut Meurah Rosnelly ◽  
...  
Keyword(s):  
Tannic Acid ◽  
Water Flux ◽  
Membrane Properties ◽  
Pvdf Membrane ◽  
Polyvinylidene Difluoride ◽  
Alkaline Conditions ◽  
Dope Solution ◽  
The Stability ◽  
Filtration Properties ◽  
Potential Use

Potential use of tannic acid (TA) as an additive for fabrication of polyvinylidene difluoride (PVDF) membrane was investigated. The TA was introduced by blending into the dope solution with varying concentrations of 0, 1, 1.5, and 2 wt%. The prepared membranes were characterized and evaluated for filtration of humic acid (HA) solution. The stability of the membrane under harsh treatment was also evaluated by one-week exposure to acid and alkaline conditions. The results show that TA loadings enhanced the resulting membrane properties. It increased the bulk porosity, water uptake, and hydrophilicity, which translated into improved clean water flux from 15.4 L/m2.h for the pristine PVDF membrane up to 3.3× for the TA-modified membranes with the 2 wt% TA loading. The flux recovery ratio (FRR) of the TA-modified membranes (FRRs = 78–83%) was higher than the pristine one (FRR = 58.54%), with suitable chemical stability too. The improved antifouling property for the TA-modified membranes was attributed to their enhanced hydrophilicity thanks to improved morphology and residual TA in the membrane matric.

scholarly journals A Novel Colorimetric Nano Aptasensor for Ultrasensitive Detection of Aflatoxin B1 Based on the Exonuclease III-Assisted Signal Amplification Approach

Foods ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2568
Author(s):  
Yu Chen ◽  
Fuyuan Zhang ◽  
Ruobing Liu ◽  
Minxuan Liu ◽  
Yaxin Sang ◽  
...  
Keyword(s):  
Aflatoxin B1 ◽  
Signal Amplification ◽  
Dynamic Range ◽  
Exonuclease Iii ◽  
Relative Standard ◽  
Cereal Samples ◽  
Exo Iii ◽  
Amplification Strategy ◽  
Amplification Procedure ◽  
Better Than

The detection of aflatoxin B1 (AFB1) has recently garnered much attention on the issue of food safety. In this study, a novel and sensitive aptasensor towards AFB1 is proposed using an Exonuclease III (Exo III)-integrated signal amplification strategy. This reported sensing strategy is regulated by aptamer-functionalized nanobeads that can target AFB1; furthermore, complementary DNA (cDNA) strands can lock the immobilized aptamer strands, preventing the signal amplification function of Exo III in the absence of AFB1. The presence of AFB1 triggers the displacement of cDNA, which will then activate the Exo III-integrated signal amplification procedure, resulting in the generation of a guanine (G)-rich sequence to form a G-4/hemin DNAzyme, which can catalyze the substrate of ABTS to produce a green color. Using this method, a practical detection limit of 0.0032 ng/mL and a dynamic range of detection from 0.0032 to 50 ng/mL were obtained. Additionally, the practical application of the established sensing method for AFB1 in complex matrices was demonstrated through recovery experiments. The recovery rate and relative standard deviations (RSD) in three kinds of cereal samples ranged from 93.83% to 111.58%, and 0.82% to 7.20%, respectively, which were comparable with or better than previously reported methods.

scholarly journals Standardization of Licorice and TCM Formulations Using Eastern Blot Fingerprinting Analysis

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Yukihiro Shoyama
Keyword(s):  
Cross Reactivity ◽  
Glycyrrhetic Acid ◽  
Spleen Cells ◽  
Pvdf Membrane ◽  
Polyvinylidene Difluoride ◽  
Sugar Moiety ◽  
Eastern Blotting ◽  
Licorice Extract ◽  
Specific Reactivity ◽  
Protein Enzyme

To prepare the antiglycyrrhizin (GC) monoclonal antibody (MAb), GC was treated with NaIO4resulting in aldehyde which can be combined with carrier protein. An antigen conjugate was performed by a matrix-assisted laser desorption/ionization TOF mass spectrometry to determine the hapten numbers in the conjugate. Anti-GC MAb was prepared from a hybridoma which was fixed from the spleen cells producing anti-GC MAb and the myeloma cells after immunization. The TCM and licorice extract were developed by TLC and blotted to a polyvinylidene difluoride (PVDF) membrane. The membrane was treated by NaIO4and protein, enzyme labeled secondary MAb, and finally substrate was added. Clear spot appeared on PVDF membrane identifying GC against a background containing large amount of impurities. In eastern blotting, the GC molecule was divided into two functions. The aglycone part is recognized as an epitope and the sugar moiety can be combined to membrane. The specific reactivity of sugar moiety in the GC molecule against anti-GC MAb might be modified by the NaIO4treatment on the membrane because glycyrrhetic acid 3-O-glucuronide can be stained although the cross-reactivity is only 4.3%. Eastern blotting for GC can not only apply for the standardization of licorice and TCM, but also it can open for the other bioactive products.

scholarly journals Detection of Citrus Leaf and Seed Glycoproteins using Biotinylated Lectin Probes

HortScience ◽  
1991 ◽  
Vol 26 (7) ◽  
pp. 910-913 ◽  
Author(s):  
Randall P. Niedz ◽  
Michael G. Bausher ◽  
C. Jack Hearn
Keyword(s):  
Gel Electrophoresis ◽  
Wheat Germ ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Carbohydrate Binding ◽  
Pvdf Membrane ◽  
Polyvinylidene Difluoride ◽  
Sds Page ◽  
Background Staining ◽  
Avidin Biotin Complex

leaf and seed glycoproteins were detected after sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and electroblotting onto polyvinylidene difluoride (PVDF) membrane when probed with biotinylated lectin at 1 μg·ml-1. Four lectins representing three carbohydrate-binding groups were used as probes. A preformed avidin-biotin-complex (ABC) was used to detect the glycoprotein-bound lectins and resulted in dark bands and little background staining. Concanavalin A (ConA) and wheat germ agglutinin (WGA) resulted in the darkest-staining bands. The four Citrus spp. and one related species studied had unique seed glycoprotein profiles when probed with ConA and WGA. This procedure might be useful in clarifying citrus taxonomy, providing genetic markers, and in physiological studies involving glycoproteins.

Physiological Signal Detection Instrument Based on FPGA

2013 ◽  
Vol 850-851 ◽  
pp. 576-579
Author(s):  
Hua Qun Zhan ◽  
Bin Xu ◽  
Yong Ping Cao ◽  
Quan Jiang Liu
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
Signal Detection ◽  
Signal Amplification ◽  
Digital Signal ◽  
Physiological Signal ◽  
The Core ◽  
Detection Instrument

This paper introduces a kind of physiological signal detection instrument based on FPGA. The system uses FPGA as the core, SC0073 as the sensor, the signal amplification, filtering, A/D conversion, and finally the signal does a digital signal processing in FPGA , and under the control of FPGA, displayed on the LCD screen in time. Results show that the system is stable and have a good performance.

scholarly journals Properties of Dry Hopped Dark Beers with High Xanthohumol Content

Antioxidants ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 763
Author(s):  
Justyna Paszkot ◽  
Joanna Kawa-Rygielska ◽  
Mirosław Anioł
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Antioxidant Activity ◽  
Sulfonic Acid ◽  
Fermentation Process ◽  
Iron Ions ◽  
Color Intensity ◽  
Polyphenol Content ◽  
Acid Fermentation ◽  
Yeast Saccharomyces Cerevisiae ◽  
Opposite Tendency

The antioxidant activity of beers comes mainly from phenolic compounds and melanoidins. The aim of this research was to evaluate the effect of technological operations, especially the ethanol fermentation process using top fermentation brewer’s yeast Saccharomyces cerevisiae, on the antioxidant activity of dark dry hopped beers with a high xanthohumol content. Four beers were produced using different varieties of hops. The polyphenol content during beer processing increased at the stage of hopping and fermentation, while it decreased during aging. The ability to reduce iron ions increased for all beers compared to hopped wort. The opposite tendency was noted for the antioxidant capacity expressed as the ability to reduce the radical cation ABTS•+ generated from 2,2′-azino-bis (3-ethylbenzthiazoline-6-sulfonic acid). Fermentation and aging caused a decrease in beer color intensity. The content of 5-hydroxymethylfurfural (5-HMF) increased with the color intensity of wort, therefore in beers no presence of 5-HMF was observed. The beers were characterized by a distinctly high content of xanthohumol in the range of 1.77–3.83 mg/L and 0.85–1.19 mg/L of isoxanthohumol. The content of prenylflavonoids and bitterness of beer depended on the variety of hops used.

Sign in / Sign up

Export Citation Format

Share Document