scholarly journals Rational Design of Amphiphilic Diblock Copolymer/MWCNT Surface Modifiers and Their Application for Direct Electrochemical Sensing of DNA

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1514
Author(s):  
Larisa V. Sigolaeva ◽  
Tatiana V. Bulko ◽  
Apollinariya Yu. Konyakhina ◽  
Alexey V. Kuzikov ◽  
Rami A. Masamrekh ◽  
...  
Keyword(s):  
Electrochemical Oxidation ◽  
Diblock Copolymer ◽  
Rational Design ◽  
Diblock Copolymers ◽  
Aqueous Media ◽  
Electrochemical Sensing ◽  
Multiwalled Carbon ◽  
Surface Areas ◽  
Copolymer Structure ◽  
Great Acceleration

We demonstrate the application of amphiphilic ionic poly(n-butylmethacrylate)-block- poly(2-(dimethylamino)ethyl methacrylate) diblock copolymers (PnBMA40-b-PDMAEMA40, PnBMA40-b-PDMAEMA120, PnBMA70-b-PDMAEMA120) for dispersing multiwalled carbon nanotubes (MWCNTs) in aqueous media, a subsequent efficient surface modification of screen-printed electrodes (SPEs), and the application of the modified SPEs for DNA electrochemistry. Stable and fine aqueous dispersions of MWCNTs were obtained with PnBMAx-b-PDMAEMAy diblock copolymers, regardless of the structure of the copolymer and the amount of MWCNTs in the dispersions. The effect of the diblock copolymer structure was important when the dispersions of MWCNTs were deposited as modifying layers on surfaces of SPEs, resulting in considerable increases of the electroactive surface areas and great acceleration of the electron transfer rate. The SPE/(PnBMAx-b-PDMAEMAy + MWCNT) constructs were further exploited for direct electrochemical oxidation of the guanine (G) and adenine (A) residues in a model salmon sperm double-stranded DNA (dsDNA). Two well-defined irreversible oxidation peaks were observed at about +600 and +900 mV, corresponding to the electrochemical oxidation of G and A residues, respectively. A multi-parametric optimization of dsDNA electrochemistry enables one to get the limits of detection (LOD) as low as 5 μg/mL (0.25 μM) and 1 μg/mL (0.05 μM) for G and A residues, respectively. The achieved sensitivity of DNA assay enables quantification of the A and G residues of dsDNA in the presence of human serum and DNA in isolated human leukocytes.

scholarly journals Surface-Enhanced Oxidation and Determination of Isothipendyl Hydrochloride at an Electrochemical Sensing Film Constructed by Multiwalled Carbon Nanotubes

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
S. N. Prashanth ◽  
Shankara S. Kalanur ◽  
Nagappa L. Teradal ◽  
J. Seetharamappa
Keyword(s):  
Limit Of Detection ◽  
Biological Fluids ◽  
Differential Pulse ◽  
Electrochemical Sensing ◽  
Good Precision ◽  
Multiwalled Carbon ◽  
Limit Of Quantification ◽  
Surface Enhanced ◽  
Ph Range

The electrochemical behavior of isothipendyl hydrochloride (IPH) was investigated at bare and multiwalled-carbon-nanotube modified glassy carbon electrode (MWCNT-GCE). IPH (55 μM) showed two oxidation peaks in Britton-Robinson (BR) buffer of pH 7.0. The oxidation process of IPH was observed to be irreversible over the pH range of 2.5–9.0. The influence of pH, scan rate, and concentration of the drug on anodic peak was studied. A differential pulse voltammetric method with good precision and accuracy was developed for the determination of IPH in pure and biological fluids. The peak current was found to be linearly dependent on the concentration of IPH in the range of 1.25–55 μM. The values of limit of detection and limit of quantification were noticed to be 0.284 and 0.949 μM, respectively.

Mechanical Properties of Blends of Crystallizable Polybutadienes Containing Amorphous Polybutadiene Diblock Copolymers

1994 ◽  
Vol 67 (2) ◽  
pp. 342-347
Author(s):  
Moira Marx Nir ◽  
Robert E. Cohen
Keyword(s):  
Mechanical Properties ◽  
Molecular Weight ◽  
Surface Area ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Tensile Failure ◽  
Interfacial Surface ◽  
Failure Properties ◽  
Enhanced Properties

Abstract Tensile failure properties of syndiotactic 1,2 polybutadiene/trans 1,4 polybutadiene crystalline blends are improved by addition of 5–10% amorphous 1,2 polybutadiene/1,4 polybutadiene diblock copolymer. The effect of block molecular weight and microphase behavior of the diblock copolymer was investigated. Heterogeneous diblocks enhance blend properties to a greater extent than homogeneous diblocks. In blends with enhanced properties, percent coverage of interfacial surface area by diblock is on the order of 10%.

Electrochemical oxidation of 5-hydroxymethylfurfural on ternary metal-organic frameworks nanoarrays: enhancement from electronic structure modulation

2021 ◽  
Author(s):  
Xiaojue Bai ◽  
Wenxiu He ◽  
Xingyu Lu ◽  
Yu Fu ◽  
Wei Qi
Keyword(s):  
Electronic Structure ◽  
Carboxylic Acid ◽  
Electrochemical Oxidation ◽  
Rational Design ◽  
Metal Organic Frameworks ◽  
Highly Active ◽  
Ternary Metal ◽  
Metal Organic ◽  
Structure Modulation

The rational design and exploitation of highly active and stable catalysts for the electrochemical oxidation of biomass-derived 5-hydroxymethylfurfural (HMF) to valuable chemical 2,5-furandi-carboxylic acid (FDCA), is of great significance. Herein,...

Multiwalled Carbon Nanotubes Covered with Cobalt (II) Phthalocyanine by In Situ Synthesis and its Electrochemical Sensing Performance towards DA and UA

2014 ◽  
Vol 809-810 ◽  
pp. 43-52
Author(s):  
Hua Hua Wang ◽  
Nan Li ◽  
Kai Li ◽  
Yuan Bu ◽  
Wen Le Dai ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Multiwalled Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Simultaneous Detection ◽  
Thick Layer ◽  
Electrochemical Sensing ◽  
Multiwalled Carbon ◽  
X Ray ◽  
Platinum Particles

Multiwalled carbon nanotubes (MWCNTs) as an excellent supporter covered with a thick layer of cobalt phthalocyanine (CoPc) were prepared by in-situ synthesis. Platinum particles were adopted to enhance the conductivity of CoPc-MWCNTs. The final nanocomposite Pt-CoPc-MWCNTs was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). Strong aromatic π-π stacking between MWCNTs and CoPc made CoPc in-situ forming on MWCNTs. With homogeneous thickness of CoPc covered on the MWCNTs and Pt particles equally distributed, the nanocomposite was used as electrocatalyst. The electrochemical properties of the composite got researched by casting the dispersion of Pt-CoPc-MWCNTs on the glassy carbon electrode. Compared with other modified electrodes, Pt-CoPc-MWCNTs/GC electrode exhibited excellent electrochemical activity towards dopamine (DA) and uric acid (UA). Linear responses for DA and UA were obtained in the ranges of 5 to 170 μM and 5 to 100 μM, and limits of detection were 2.6 and 1.4 μM (S/N= 3), respectively. Simultaneous detection of DA and UA in the presence of ascorbic acid (AA) also displayed selective property, with no interference to each other.

The Ordered Bicontinuous Double Diamond Structure in Binary Blends of Diblock Copolymer and Homopolymer.

1989 ◽  
Vol 171 ◽  
Author(s):  
Karen I. Winey ◽  
Edwin L. Thomas
Keyword(s):  
Molecular Weight ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Composition Range ◽  
Volume Fraction ◽  
Diamond Structure ◽  
Binary Blends ◽  
Resultant Effect ◽  
Strong Segregation ◽  
Double Diamond

ABSTRACTWe report the observation of the ordered bicontinuous double diamond (OBDD) structure in binary blends of poly(styrene-isoprene) diblock copolymer and homopolystyrene. The overall polystyrene volume fraction range is 64 - 67 PSvol% for the OBDD structure in binary blends of a lamellar diblock (SI 27/22) and a homopolymer (14.0 hPS). This composition range is approximately within the polystyrene volume fraction range established for pure diblock copolymers in the strong segregation regime having the OBDD structure. Ordered lamellae are observed at approximately 65 PSvol% when the homopolystyrene molecular weight is greater than the molecular weight of the polystyrene block of the copolymer. This observation is discussed in terms of the decreased degree of mixing between the homopolymer and the corresponding block and the resultant effect on the interfacial curvature.

Photoisomerization of electroactive polyimide/multiwalled carbon nanotube composites on the effect of electrochemical sensing for ascorbic acid

2014 ◽  
Vol 64 (3) ◽  
pp. 373-382 ◽  
Author(s):  
Kung-Chin Chang ◽  
Chien-Ming Chu ◽  
Chi-Hao Chang ◽  
Hsiao-Tung Cheng ◽  
Sheng-Chieh Hsu ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Carbon Nanotube ◽  
Multiwalled Carbon Nanotube ◽  
Electrochemical Sensing ◽  
Multiwalled Carbon ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites

Self-Assemble Behavior of Amphiphilic Diblock Copolymer of Methoxy Poly (Ethylene Glycol)/Polyester

2011 ◽  
Vol 295-297 ◽  
pp. 11-15
Author(s):  
Hao Zhou ◽  
Qing Hong Liang ◽  
Xiang Ke Shi ◽  
Li Hua Lu ◽  
Li Qun Zhang ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Light Scattering ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Average Diameter ◽  
Core Shell ◽  
Amphiphilic Diblock Copolymer ◽  
Amphiphilic Diblock Copolymers ◽  
Methoxy Polyethylene Glycol ◽  
Solution Polycondensation

Amphiphilic diblock copolymers based on methoxy polyethylene glycol (MePEG), 1, 6-hexanediol and maleic anhydride with different molar composition were synthesized by solution polycondensation. Self-assemble behavior of amphiphilic diblock copolymer in different solvents by dialyzing technique was discussed. The micelle morphologhy was observed by TEM. It was found that well core-shell MePEG1900/Polyester 2162 copolymer nanoparticles can be formed by self-assemble in acetone solution. In addition, the size of nanospheres measured using dynamic light scattering exhibited a narrow monodisphere size distribution and an average diameter in the ranger of less than 200nm.

Mussel-inspired construction of thermo-responsive double-hydrophilic diblock copolymers-decorated reduced graphene oxide as effective catalyst supports for highly dispersed superfine Pd nanoparticles

Nanoscale ◽  
2018 ◽  
Vol 10 (26) ◽  
pp. 12487-12496 ◽  
Author(s):  
Haichao Duan ◽  
Yu Yang ◽  
Jianhua Lü ◽  
Changli Lü
Keyword(s):  
Graphene Oxide ◽  
Catalytic Activity ◽  
Reduced Graphene Oxide ◽  
Diblock Copolymer ◽  
Diblock Copolymers ◽  
Pd Nanoparticles ◽  
Catalyst Supports ◽  
High Catalytic Activity ◽  
Reduced Graphene ◽  
Highly Dispersed

We report a facile, mussel-inspired construction of a thermo-responsive diblock copolymer-anchored rGO support for superfine PdNPs with high catalytic activity.

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