scholarly journals DNA-based biosensors with external Nafion and chitosan membranes for the evaluation of the antioxidant activity of beer, coffee, and tea

2014 ◽  
Vol 12 (5) ◽  
pp. 604-611 ◽  
Author(s):  
Lenka Hlavatá ◽  
Vlastimil Vyskočil ◽  
Katarína Beníková ◽  
Monika Borbélyová ◽  
Ján Labuda
Keyword(s):  
Hydroxyl Radicals ◽  
Antioxidant Properties ◽  
Chitosan Film ◽  
Outer Sphere ◽  
Black Tea ◽  
Layer By Layer ◽  
Dna Biosensors ◽  
Layer Deposition ◽  
Medium Exchange ◽  
Antioxidant Properties Of Beverages

AbstractNovel electrochemical DNA-based biosensors with outer-sphere Nafion and chitosan protective membranes were prepared for the evaluation of antioxidant properties of beverages (beer, coffee, and black tea) against prooxidant hydroxyl radicals. A carbon working electrode of a screen-printed three-electrode assembly was modified using a layer-by-layer deposition technique with low molecular weight double-stranded DNA and a Nafion or chitosan film. The membrane-covered DNA biosensors were initially tested with respect to their voltammetric and impedimetric response after the incubation of the beverage and the medium exchange for the solution of the redox indicator [Fe(CN)6]3−/4−. While the Nafion-protected biosensor proved to be suitable for beer and black tea extracts, the chitosan-protected biosensor was successfully used in a coffee extract. Afterwards, the applicability was successfully verified for these biosensors for the detection of a deep degradation of the surface-attached DNA at the incubation in the cleavage agent (hydroxyl radicals generated via Fenton reaction) and for the evaluation of antioxidant properties of coffee and black tea extracts against prooxidant hydroxyl radicals. The investigation of the novel biosensors with a protective membrane represents a significant contribution to the field of electrochemical DNA biosensors utilization.

scholarly journals DNA-based biosensors with polyvinyl alcohol external membrane as a tool for the evaluation of antioxidant activity of white wines

2015 ◽  
Vol 8 (2) ◽  
pp. 197-202 ◽  
Author(s):  
Veronika Svitková ◽  
Lucia Steffelová ◽  
Jana Blaškovičová ◽  
Ján Labuda
Keyword(s):  
Significant Contribution ◽  
Antioxidant Properties ◽  
Outer Sphere ◽  
Layer By Layer ◽  
Dna Biosensors ◽  
White Wines ◽  
Double Stranded Dna ◽  
Layer Deposition ◽  
Redox Indicator ◽  
Working Procedure

AbstractElectrochemical DNA-based biosensors with external protective membranes were prepared for the evaluation of antioxidant properties of white wines against pro-oxidant hydroxyl radicals. A glassy carbon working electrode (GCE) was modified using a layer-by-layer deposition technique with low molecular weight double stranded DNA and an outer sphere polymer film membrane of Nafion, chitosan or polyvinylalcohol. The composition of a working procedure with membrane-covered DNA biosensors were optimized with respect to their voltammetric response in solution of the DNA redox indicator [Fe(CN)6]3-/4-after the incubation in white wines. Polyvinylalcohol (PVA) film was proved to be the suitable membrane. The PVA/DNA/GCE biosensor was used for the detection of a deep degradation of the surface-attached DNA at the incubation in the cleavage agent and for the evaluation of antioxidant properties of white wines at the incubation in mixtures of cleavage agent and wine. The investigation of the biosensors with protective membranes represents a significant contribution to utilization of the electrochemical DNA based biosensors for practical purposes.

scholarly journals Development and Characterization of Functional Starch-Based Films Incorporating Free or Microencapsulated Spent Black Tea Extract

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3898
Author(s):  
Surakshi Wimangika Rajapaksha ◽  
Naoto Shimizu
Keyword(s):  
Antioxidant Activity ◽  
Lipid Oxidation ◽  
Food Packaging ◽  
Uv Light ◽  
Antioxidant Properties ◽  
Black Tea ◽  
Wall Material ◽  
Food Simulants ◽  
Black Tea Extract ◽  
Tea Extract

Antioxidant polyphenols in black tea residue are an underused source of bioactive compounds. Microencapsulation can turn them into a valuable functional ingredient for different food applications. This study investigated the potential of using spent black tea extract (SBT) as an active ingredient in food packaging. Free or microencapsulated forms of SBT, using a pectin–sodium caseinate mixture as a wall material, were incorporated in a cassava starch matrix and films developed by casting. The effect of incorporating SBT at different polyphenol contents (0.17% and 0.34%) on the structural, physical, and antioxidant properties of the films, the migration of active compounds into different food simulants and their performance at preventing lipid oxidation were evaluated. The results showed that adding free SBT modified the film structure by forming hydrogen bonds with starch, creating a less elastic film with antioxidant activity (173 and 587 µg(GAE)/g film). Incorporating microencapsulated SBT improved the mechanical properties of active films and preserved their antioxidant activity (276 and 627 µg(GAE)/g film). Encapsulates significantly enhanced the release of antioxidant polyphenols into both aqueous and fatty food simulants. Both types of active film exhibited better barrier properties against UV light and water vapour than the control starch film and delayed lipid oxidation up to 35 d. This study revealed that starch film incorporating microencapsulated SBT can be used as a functional food packaging to protect fatty foods from oxidation.

Radical-triggered cross-linking for molecular layer deposition of SiAlCOH hybrid thin films

2021 ◽  
Author(s):  
Kristina Ashurbekova ◽  
Karina Ashurbekova ◽  
Iva Saric ◽  
Evgeny Modin ◽  
Mladen Petravic ◽  
...  
Keyword(s):  
Thin Film ◽  
Film Growth ◽  
Molecular Layer ◽  
Thin Film Growth ◽  
Cross Linking ◽  
Layer By Layer ◽  
Molecular Layer Deposition ◽  
Layer Deposition ◽  
Hybrid Thin Films ◽  
Enhanced Stability

We developed a thin film growth with a radical-initiated cross-linking of vinyl groups in a layer-by-layer manner via molecular layer deposition (MLD). The cross-linked film exhibited improved properties like 12% higher density and enhanced stability compared to the non-cross-linked film.

All-nanoparticle layer-by-layer coatings for Mid-IR on-chip gas sensing

2020 ◽  
Vol 56 (91) ◽  
pp. 14283-14286
Author(s):  
Diana Al Husseini ◽  
Junchao Zhou ◽  
Daniel Willhelm ◽  
Trevor Hastings ◽  
Gregory S. Day ◽  
...  
Keyword(s):  
Optical Waveguides ◽  
Gas Sensing ◽  
Layer By Layer ◽  
Precise Control ◽  
Nanoparticle Layer ◽  
Withdrawal Speed ◽  
Layer Deposition ◽  
Nanoparticle Coatings ◽  
On Chip

Functionalization of optical waveguides with submicron all-nanoparticle coatings significantly enhanced the detection of acetone. Such coatings were enabled via precise control of the substrate withdrawal speed using the layer-by-layer deposition.

Layer-by-Layer Deposition of Polyelectrolytes. Dipping versus Spraying

Langmuir ◽  
2009 ◽  
Vol 25 (2) ◽  
pp. 1224-1232 ◽  
Author(s):  
Marta Kolasinska ◽  
Rumen Krastev ◽  
Thomas Gutberlet ◽  
Piotr Warszynski
Keyword(s):  
Layer By Layer ◽  
Layer Deposition

Mechanically Stable Antireflection and Antifogging Coatings Fabricated by the Layer-by-Layer Deposition Process and Postcalcination

Langmuir ◽  
2008 ◽  
Vol 24 (19) ◽  
pp. 10851-10857 ◽  
Author(s):  
Lianbin Zhang ◽  
Yang Li ◽  
Junqi Sun ◽  
Jiacong Shen
Keyword(s):  
Deposition Process ◽  
Layer By Layer ◽  
Layer Deposition
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