scholarly journals Abnormal Anionic Porphyrin Sensing Effect for HER2 Gene Related DNA Detection via Impedance Difference between MWCNTs and Single-Stranded DNA or Double-Stranded DNA

Molecules ◽  
2018 ◽  
Vol 23 (10) ◽  
pp. 2688 ◽  
Author(s):  
Jingheng Ning ◽  
Long Liu ◽  
Xin Luo ◽  
Min Wang ◽  
Donglin Liu ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Electrochemical Sensing ◽  
Her2 Gene ◽  
Single Stranded Dna ◽  
Double Stranded Dna ◽  
Efficient Detection ◽  
Target Dna ◽  
Cnts Surface

Human epidermal growth factor receptor 2 (HER2) is a key tumor marker for several common and deadly cancers. It is of great importance to develop efficient detection methods for its over-expression. In this work, an electrochemical impedance spectroscopy (EIS) method adjustable by anionic porphyrin for HER2 gene detection has been proposed, based on the impedance difference between multi-walled carbon nanotubes (MWCNTs) and DNA. The interesting finding herein is that with the addition of anionic porphyrin, i.e., meso-tetra(4-sulfophenyl)-porphyrin (TSPP), the impedance value obtained at a glass carbon electrode (GCE) modified with MWCNTs and a single stranded DNA (ssDNA), the probe DNA that might be assembled tightly onto MWCNTs through π-π stacking interaction, gets a slight decrease; however, the impedance value from a GCE modified with MWCNTs and a double stranded DNA (dsDNA), the hybrid of the probe DNA with a target DNA, which might be assembled loosely onto MWCNTs for the screening effect of phosphate backbones in dsDNA, gets an obvious decrease. The reason may be that on the one hand, being rich in negative sulfonate groups, TSPP will try to push DNA far away from CNTs surface due to its strong electrostatic repulsion towards DNA; on the other hand, rich in planar phenyl or pyrrole rings, TSPP will compete with DNA for the surface of CNTs since it can also be assembled onto CNTs through conjugative interactions. In this way, the “loosely assembled” dsDNA will be repelled by this anionic porphyrin and released off CNTs surface much more than the “tightly assembled” ssDNA, leading to a bigger difference in the impedance value between dsDNA and ssDNA. Thus, through the amplification effect of TSPP on the impedance difference, the perfectly matched target DNA could be easily determined by EIS without any label. Under the optimized experimental conditions, this electrochemical sensor shows an excellent linear response to target DNA in a concentration range of 2.0 × 10−11–2.0 × 10−6 M with a limit of detection (LOD) of 6.34 × 10−11 M (S/N = 3). This abnormally sensitive electrochemical sensing performance resulting from anionic porphyrin for DNA sequences specific to HER2 gene will offer considerable promise for tumor diagnosis and treatment.

scholarly journals Supramolecular assemblies of carbon nanocoils and tetraphenylporphyrin derivatives for sensing of catechol and hydroquinone in aqueous solution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Syeda Aqsa Batool Bukhari ◽  
Habib Nasir ◽  
Lujun Pan ◽  
Mehroz Tasawar ◽  
Manzar Sohail ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Linear Trend ◽  
Differential Pulse ◽  
Peak Potential ◽  
Limit Of Quantification ◽  
Efficient Detection ◽  
Good Repeatability ◽  
Ft Ir ◽  
Pulse Voltammetry

AbstractNon-enzymatic electrochemical detection of catechol (CC) and hydroquinone (HQ), the xenobiotic pollutants, was carried out at the surface of novel carbon nanocoils/zinc-tetraphenylporphyrin (CNCs/Zn-TPP) nanocomposite supported on glassy carbon electrode. The synergistic effect of chemoresponsive activity of Zn-TPP and a large surface area and electron transfer ability of CNCs lead to efficient detection of CC and HQ. The nanocomposite was characterized by using FT-IR, UV/vis. spectrophotometer, SEM and energy dispersive X-ray spectroscopy (EDS). Cyclic voltammetry, differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy were used for the electrochemical studies. CNCs/Zn-TPP/GCE nanosensor displayed a limit of detection (LOD), limit of quantification (LOQ) and sensitivity for catechol as 0.9 µM, 3.1 µM and 0.48 µA µM−1 cm−2, respectively in a concentration range of 25–1500 µM. Similarly, a linear trend in the concentration of hydroquinone detection was observed between 25 and 1500 µM with an LOD, LOQ and sensitivity of 1.5 µM, 5.1 µM and 0.35 µA µM−1 cm−2, respectively. DPV of binary mixture pictured well resolved peaks with anodic peak potential difference, ∆Epa(CC-HQ), of 110 mV showing efficient sensing of CC and HQ. The developed nanosensor exhibits stability for up to 30 days, better selectivity and good repeatability for eight measurements (4.5% for CC and 5.4% for HQ).

scholarly journals Heterogeneous nuclear ribonucleoprotein D0B is a sequence-specificDNA-binding protein

1999 ◽  
Vol 338 (2) ◽  
pp. 417-425 ◽  
Author(s):  
Mate TOLNAY ◽  
Lyudmila A. VERESHCHAGINA ◽  
George C. TSOKOS
Keyword(s):  
Dna Sequences ◽  
Rna Binding ◽  
Binding Protein ◽  
Double Helix ◽  
Physiological Role ◽  
Single Stranded Dna ◽  
Heterogeneous Nuclear Ribonucleoprotein ◽  
Double Stranded Dna ◽  
Nuclear Ribonucleoprotein

Complement receptor 2 (CR2) is important in the regulation of the B lymphocyte response; the regulation of its expression is therefore of central importance. We recently reported that a 42 kDa heterogeneous nuclear ribonucleoprotein (hnRNP) is involved in the transcriptional regulation of the human CR2 gene [Tolnay, Lambris and Tsokos (1997) J. Immunol. 159, 5492–5501]. We cloned the cDNA encoding this protein and found it to be identical with hnRNP D0B, a sequence-specific RNA-binding protein. By using a set of mutated oligonucleotides, we demonstrated that the recombinant hnRNP D0B displays sequence specificity for double-stranded oligonucleotide defined by the CR2 promoter. We conducted electrophoretic mobility-shift assays to estimate the apparent Kd of hnRNP D0B for the double-stranded DNA motif and found it to be 59 nM. Interestingly, hnRNP D0B displayed affinities of 28 and 18 nM for the sense and anti-sense strands of the CR2 promoter-defined oligonucleotide respectively. The significantly greater binding affinity of hnRNP D0B for single-stranded DNA than for double-stranded DNA suggests that the protein might melt the double helix. The intranuclear concentration of sequence-specific protein was estimated to be 250–400 nM, indicating that the protein binds to the CR2 promoter in vivo. Co-precipitation of a complex formed in vivo between hnRNP D0B and the TATA-binding protein demonstrates that hnRNP D0B interacts with the basal transcription apparatus. Our results suggest a new physiological role for hnRNP D0B that involves binding to double- and single-stranded DNA sequences in a specific manner and functioning as a transcription factor.

scholarly journals Electrochemical Sensing of Idarubicin—DNA Interaction Using Electropolymerized Azure B and Methylene Blue Mediation

Chemosensors ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 33
Author(s):  
Anastasia Goida ◽  
Yurii Kuzin ◽  
Vladimir Evtugyn ◽  
Anna Porfireva ◽  
Gennady Evtugyn ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Biological Fluids ◽  
Dna Interaction ◽  
Electrochemical Sensing ◽  
Dna Sensor ◽  
Azure B ◽  
Fish Sperm ◽  
Highly Sensitive

A highly sensitive electrochemical DNA sensor for detection of the chemotherapeutic drug idarubicin mediated by Methylene blue (MB) has been developed. DNA from fish sperm has been immobilized at the electropolymerized layers of Azure B. The incorporation of MB into the DNA layers substantially increased the sensor sensitivity. The concentration range for idarubicin determination by cyclic voltammetry was from 1 fM to 0.1 nM, with a limit of detection (LOD) of 0.3 fM. Electrochemical impedance spectroscopy (EIS) in the presence of a redox probe ([Fe(CN)6]3−/4−) allowed for the widening of a linear range of idarubicin detection from 1 fM to 100 nM, retaining LOD 0.3 fM. The DNA sensor has been tested in various real and artificial biological fluids with good recovery ranging between 90–110%. The sensor has been successfully used for impedimetric idarubicin detection in medical preparation Zavedos®. The developed DNA biosensor could be useful for the control of the level of idarubicin during cancer therapy as well as for pharmacokinetics studies.

scholarly journals An Internalin A Probe-Based Genosensor forListeria monocytogenesDetection and Differentiation

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Laura Bifulco ◽  
Angela Ingianni ◽  
Raffaello Pompei
Keyword(s):  
Dna Sequences ◽  
Gold Surface ◽  
Differential Pulse ◽  
Gene Probe ◽  
Self Assembled Monolayer ◽  
Double Stranded Dna ◽  
Target Dna ◽  
Pulse Voltammetry ◽  
Genus One ◽  
Internalin A

Internalin A (InlA), a protein required forListeria monocytogenesvirulence, is encoded by theinlA gene, which is only found in pathogenic strains of this genus. One of the best ways to detect and confirm the pathogenicity of the strain is the detection of one of the virulence factors produced by the microorganism. This paper focuses on the design of an electrochemical genosensor used to detect theinlA gene inListeriastrains without labelling the target DNA. The electrochemical sensor was obtained by immobilising aninlA gene probe (single-stranded oligonucleotide) on the surfaces of screen-printed gold electrodes (Au-SPEs) by means of a mercaptan-activated self-assembled monolayer (SAM). The hybridisation reaction occurring on the electrode surface was electrochemically transduced by differential pulse voltammetry (DPV) using methylene blue (MB) as an indicator. The covalently immobilised single-stranded DNA was able to selectively hybridise to its complementary DNA sequences in solution to form double-stranded DNA on the gold surface. A significant decrease of the peak current of the voltammogram (DPV) upon hybridisation of immobilised ssDNA was recorded. Whole DNA samples ofL. monocytogenesstrains could be discriminated from other nonpathogenicListeriaspecies DNA with theinlA gene DNA probe genosensor.

scholarly journals Differential Pulse Voltammetric Electrochemical Sensor for the Detection of Etidronic Acid in Pharmaceutical Samples by Using rGO-Ag@SiO2/Au PCB

Nanomaterials ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 1368 ◽  
Author(s):  
Sathish Panneer Selvam ◽  
Somasekhar R. Chinnadayyala ◽  
Sungbo Cho ◽  
Kyusik Yun
Keyword(s):  
Electrochemical Sensor ◽  
Active Sites ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Differential Pulse ◽  
Electrochemical Sensing ◽  
Etidronic Acid ◽  
Active Surface Area ◽  
Transfer Resistance ◽  
Pharmaceutical Samples

An rGO-Ag@SiO2 nanocomposite-based electrochemical sensor was developed to detect etidronic acid (EA) using the differential pulse voltammetric (DPV) technique. Rapid self-assembly of the rGO-Ag@SiO2 nanocomposite was accomplished through probe sonication. The developed rGO-Ag@SiO2 nanocomposite was used as an electrochemical sensing platform by drop-casting on a gold (Au) printed circuit board (PCB). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) confirmed the enhanced electrochemical active surface area (ECASA) and low charge transfer resistance (Rct) of the rGO-Ag@SiO2/Au PCB. The accelerated electron transfer and the high number of active sites on the rGO-Ag@SiO2/Au PCB resulted in the electrochemical detection of EA through the DPV technique with a limit of detection (LOD) of 0.68 μM and a linear range of 2.0–200.0 μM. The constructed DPV sensor exhibited high selectivity toward EA, high reproducibility in terms of different Au PCBs, excellent repeatability, and long-term stability in storage at room temperature (25 °C). The real-time application of the rGO-Ag@SiO2/Au PCB for EA detection was investigated using EA-based pharmaceutical samples. Recovery percentages between 96.2% and 102.9% were obtained. The developed DPV sensor based on an rGO-Ag@SiO2/Au PCB could be used to detect other electrochemically active species following optimization under certain conditions.

scholarly journals Voltammetric Amitriptyline Determination Using a Metal-Free Electrode Based on Phosphorus-Doped Multi-Walled Carbon Nanotubes

2022 ◽  
Author(s):  
Chanakarn Sanguarnsak ◽  
Kiattisak Promsuwan ◽  
Jenjira Saichanapan ◽  
Asamee Soleh ◽  
Kasrin Saisahas ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Electrochemical Sensing ◽  
Urine Samples ◽  
Electrochemical Characteristics ◽  
Sensing Element ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Phosphorus Doped

Abstract A new electrode material of phosphorus-doped multi-walled carbon nanotubes (P-MWCNTs) was developed as an electrochemical sensing element for amitriptyline (AMT). P-MWCNTs were hydrothermally synthesized and drop casted on a glassy carbon electrode (P-MWCNTs/GCE). The P-MWCNTs were morphologically, chemically and structurally characterized. The electrochemical characteristics of the P-MWCNTs/GCE were investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and adsorptive stripping voltammetry (AdSV). The P-MWCNTs increased electron transfer at the GCE and the electrochemical conductivity of the electrode. Electrocatalytic activity toward the oxidation of AMT was excellent. In the optimal voltammetric condition, the P-MWCNTs/GCE produced linear ranges of 0.50 to 10 µg mL-1 and 10 to 40 µg mL-1. The limit of detection (LOD) and limit of quantification (LOQ) were 0.15 µg mL-1 (0.54 µM) and 0.52 µg mL-1 (1.80 µM), respectively. The developed sensor displayed good repeatability, reproducibility and specificity. The sensor successfully quantified AMT in pharmaceutical tablets, giving results consistent with spectrophotometric analysis. The sensor achieved recoveries from 98±2% to 101±5% from spiked urine samples. The proposed sensor could be applied to determine AMT in pharmaceutical and urine samples for forensic toxicology.

scholarly journals Label free, electric field mediated ultrasensitive electrochemical point-of-care device for CEA detection

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
B. Chakraborty ◽  
A. Das ◽  
N. Mandal ◽  
N. Samanta ◽  
N. Das ◽  
...  
Keyword(s):  
Electric Field ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Point Of Care ◽  
Low Cost ◽  
Zno Nanorods ◽  
Hybrid Nanostructures ◽  
Electrochemical Sensing ◽  
Label Free ◽  
Electron Transfer Rate

AbstractDeveloping point-of-care (PoC) diagnostic platforms for carcinoembryonic antigen detection is essential. However, thefew implementations of transferring the signal amplification strategies in electrochemical sensing on paper-based platforms are not satisfactory in terms of detection limit (LOD). In the quest for pushing down LOD, majority of the research has been targeted towards development of improved nanostructured substrates for entrapping more analyte molecules and augmenting the electron transfer rate to the working electrode. But, such approaches have reached saturation. This paper focuses on enhancing the mass transport of the analyte towards the sensor surface through the application of an electric field, in graphene-ZnO nanorods heterostructure. These hybrid nanostructures have been deposited on flexible polyethylene terephthalate substrates with screen printed electrodes for PoC application. The ZnO nanorods have been functionalized with aptamers and the working sensor has been integrated with smartphone interfaced indigenously developed low cost potentiostat. The performance of the system, requiring only 50 µl analyte has been evaluated using electrochemical impedance spectroscopy and validated against commercially available ELISA kit. Limit of detection of 1 fg/ml in human serum with 6.5% coefficient of variation has been demonstrated, which is more than three orders of magnitude lower than the existing attempts on PoC device.

scholarly journals Targeted transformation of Ascobolus immersus and de novo methylation of the resulting duplicated DNA sequences.

1989 ◽  
Vol 9 (7) ◽  
pp. 2818-2827 ◽  
Author(s):  
C Goyon ◽  
G Faugeron
Keyword(s):  
Dna Sequences ◽  
Cytosine Methylation ◽  
De Novo ◽  
Wild Type Allele ◽  
Wild Type ◽  
Single Stranded Dna ◽  
Type Allele ◽  
Double Stranded Dna ◽  
Ascobolus Immersus

To develop a method to modify genomic sequences in Ascobolus immersus by precisely reintroducing defined DNA segments previously manipulated in vitro, we investigated the effect of transforming DNA conformation on recombination with chromosomal sequences. Circular single-stranded DNA carrying the met2 gene and double-stranded DNA linearized by cutting within the met2 gene both transformed protoplasts of a met2 mutant strain of A. immersus to prototrophy. In contrast to the equivalent circular double-stranded DNA, which chiefly integrated at nonhomologous chromosomal sites, single-stranded and double-stranded cut DNAs recombined primarily with the homologous chromosomal met2 sequence. Of the single-stranded DNA transformants, 65% resulted from replacement of the resident met2 mutation by the exogenous wild-type allele. In 70% of the double-stranded-cut DNA transformants, one or more copies of the transforming DNA had integrated at the met2 locus, leading to tandem duplications of the met2 target region separated by plasmid DNA. These duplicated sequences could recombine, leading to progeny containing only one copy of the met2 region. This resulted in a precise gene replacement if the wild-type allele had been retained. In addition, we show that newly duplicated sequences were most often de novo methylated at the cytosine residues during the sexual phase. Cytosine methylation was associated with inactivation of the integrated met2 gene(s) in segregants of crosses. However, methylation was not accurately maintained at each DNA replication cycle, so that Met- segregants recovered a wild-type phenotype through successive mitotic divisions. This finding indicated that met2 genes were silenced by methylation alone.

Targeted transformation of Ascobolus immersus and de novo methylation of the resulting duplicated DNA sequences

1989 ◽  
Vol 9 (7) ◽  
pp. 2818-2827
Author(s):  
C Goyon ◽  
G Faugeron
Keyword(s):  
Dna Sequences ◽  
Cytosine Methylation ◽  
De Novo ◽  
Wild Type Allele ◽  
Wild Type ◽  
Single Stranded Dna ◽  
Type Allele ◽  
Double Stranded Dna ◽  
Ascobolus Immersus

To develop a method to modify genomic sequences in Ascobolus immersus by precisely reintroducing defined DNA segments previously manipulated in vitro, we investigated the effect of transforming DNA conformation on recombination with chromosomal sequences. Circular single-stranded DNA carrying the met2 gene and double-stranded DNA linearized by cutting within the met2 gene both transformed protoplasts of a met2 mutant strain of A. immersus to prototrophy. In contrast to the equivalent circular double-stranded DNA, which chiefly integrated at nonhomologous chromosomal sites, single-stranded and double-stranded cut DNAs recombined primarily with the homologous chromosomal met2 sequence. Of the single-stranded DNA transformants, 65% resulted from replacement of the resident met2 mutation by the exogenous wild-type allele. In 70% of the double-stranded-cut DNA transformants, one or more copies of the transforming DNA had integrated at the met2 locus, leading to tandem duplications of the met2 target region separated by plasmid DNA. These duplicated sequences could recombine, leading to progeny containing only one copy of the met2 region. This resulted in a precise gene replacement if the wild-type allele had been retained. In addition, we show that newly duplicated sequences were most often de novo methylated at the cytosine residues during the sexual phase. Cytosine methylation was associated with inactivation of the integrated met2 gene(s) in segregants of crosses. However, methylation was not accurately maintained at each DNA replication cycle, so that Met- segregants recovered a wild-type phenotype through successive mitotic divisions. This finding indicated that met2 genes were silenced by methylation alone.

scholarly journals Electrochemical Sensing of Interactions between DNA and Charged Macrocycles

Chemosensors ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 347
Author(s):  
Tatjana Kulikova ◽  
Pavel Padnya ◽  
Igor Shiabiev ◽  
Alexey Rogov ◽  
Ivan Stoikov ◽  
...  
Keyword(s):  
Surface Layer ◽  
Electrostatic Interactions ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Chemical Species ◽  
Electrochemical Sensing ◽  
Future Application ◽  
Diffusional Permeability ◽  
Electrode Interface ◽  
Small Chemical

In this work, we investigated aggregation of native DNA and thiacalix[4]arene derivative bearing eight terminal amino groups in cone configuration using various redox probes on the glassy carbon electrode. It was shown that sorption transfer of the aggregates on the surface of the electrode covered with carbon black resulted in changes in electrostatic interactions and diffusional permeability of the surface layer. Such changes alter the signals of ferricyanide ion, methylene green and hydroquinone as redox probes to a degree depending on their specific interactions with DNA and own charge. Inclusion of DNA in the surface layer was independently confirmed by scanning electron microscopy, electrochemical impedance spectroscopy and experiments with doxorubicin as a model intercalator. Thermal denaturing of DNA affected the charge separation on the electrode interface and the signals of redox probes. Using hydroquinone, less sensitive to electrostatic interactions, made it possible to determine from 10 pM to 1.0 nM doxorubicin (limit of detection 3 pM) after 10 min incubation. Stabilizers present in the commercial medications did not alter the signal. The DNA sensors developed can find future application in the assessment of the complexes formed by DNA and macrocycles as delivery agents for small chemical species.

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