‘Switch-on’ DNA sensor based on poly (p-phenylene vinylenes) bound tentacle probes

2015 ◽  
Vol 87 (7) ◽  
pp. 707-715 ◽  
Author(s):  
Anupama R. Gulur Srinivas ◽  
David Barker ◽  
Jadranka Travas-Sejdic
Keyword(s):  
Magnetic Beads ◽  
Food Contamination ◽  
Medical Diagnostics ◽  
Sensor Design ◽  
Dna Sensor ◽  
Environment Monitoring ◽  
Target Dna ◽  
Highly Sensitive ◽  
Wide Range ◽  
Assay Time

AbstractThe development of highly sensitive and selective DNA sensors has fuelled applications in a wide range of fields including medical diagnostics, forensics, biodefense, food contamination and environment monitoring. We demonstrate a novel superquenching based DNA sensor with “switch-on” readout using poly(p-phenylenevinylene) (PPV) coated magnetic beads (PPV-MagSi) and quencher functionalized tentacle probes (TP). The sensor design utilizes signal amplification properties of PPV and cooperativity of TPs to monitor hybridization of target oligonucleotides (ONs). The switch-on sensor exhibits excellent sensitivity and selectively discriminates mismatches in the target DNA sequence. Two novel anionic PPVs – poly (6,6′-((2-methyl-5-((E)-4-((E)-prop-1-en-1-yl)styryl)-1,4-phenylene)-bis(oxy) dihexanoic acid) (PMDH) and poly (6,6′-((2-((E)-2,5-bis(2-methoxyethoxy)-4-((E)-prop-1-en-1-yl)styryl)-5-methyl-1,4-phenylene)-bis-(oxy)) di-hexanoic acid) (PDMonoG) were tested and compared against each other as part of the sensor design. The employed hairpin TPs possess further advantages of avoiding labelling of target ON, increased selectivity and sensitivity; faster assay time, and capability of magnetically controlled deployment and separation of PPV-MagSi beads.

Multi-walled Carbon Nanotubes/Manganese Dioxide Nano- flowers-like/Polyaniline Nanowires Nanocomposite Modified Electrode: A New Platform for a Highly Sensitive Electrochemical Impedance DNA Sensor

2021 ◽  
Author(s):  
Tuan Chu ◽  
Luyen Thi Tran ◽  
Hoang Vinh Tran ◽  
Trung Tran ◽  
Nghia Trong Nguyen ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Dna Sensor ◽  
Label Free ◽  
Dna Sensors ◽  
Electrochemical Dna Sensor ◽  
Target Dna ◽  
Highly Sensitive ◽  
Polyaniline Nanowires ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Abstract We describe in this report a development of label-free electrochemical DNA sensor based on a novel nanostructured electrode of multi-walled carbon nanotubes (MWCNTs)/ nano-flowers-like manganese dioxide (MnO2)/polyaniline nanowires (PANi NWs) nanocomposite. The nanocomposite was synthesized in-situ onto an interdigitated platinum microelectrode (Pt) using a combination of chemical and electrochemical synthesis methods: chemical preparation of MWCNTs/MnO2 and electropolymerization of PANi NWs. The fabricated MWCNTs/MnO2/PANi NWs was then used to develop a label-free electrochemical DNA sensor for a specific gene of Escherichia coli (E.coli) O157:H7 detection. The MWCNTs/MnO2/PANi NWs modified Pt electrode’s surface can facilitate for probe DNA strands immobilization and, therefore the electrochemical signal of the DNA sensors has been improved. The electrochemical impedance spectroscopy (EIS) measurements were conducted to investigate the output signals generated by the specific binding of probe and target DNA sequences. Obtained results indicated that the developed electrochemical biosensor can detect the target DNA in the linear range of 5 pM to 500 nM with a low limit of detection (LOD) at 4.42 × 10 –13 M. The research results demonstrated that the MWCNTs/MnO2/PANi NWs nanocomposite-based electrochemical DNA sensor has a great potential application to the development of highly sensitive and selective electrochemical DNA sensors to detect pathogenic agents.

scholarly journals Microcantilever Resonators for Ochratoxin A Detection in Food and Drinks

2017 ◽  
Author(s):  
Karin Santoro ◽  
Ambra Prelle ◽  
Davide Spadaro ◽  
Maria Lodovica Gullino ◽  
Carlo Ricciardi
Keyword(s):  
Ochratoxin A ◽  
Limit Of Detection ◽  
Animal Health ◽  
Food Contamination ◽  
Grape Juice ◽  
Calibration Plot ◽  
Highly Sensitive ◽  
Wide Range ◽  
Time In Literature ◽  
First Time

Mycotoxins food contamination represents a serious risk for consumers health. They are secondary metabolites of fungi that can be present in a wide range of foodstuffs. Ochratoxin A (OTA) is one of the most toxic compound and it is classified as a possible carcinogenic molecule. The harmful effects of OTA on human and animal health lead to a big boost to develop and optimize highly sensitive and accurate methods for OTA detection. An innovative and rapid detection method based on microcantilever resonators for ochratoxin A identification in food matrix has been developed. This work demonstrates the possibility to apply microcantilever technology in food safety field, showing for the first time in literature the successful detection of one of the most dangerous mycotoxin in different food matrixes both solids and liquids, such as green coffee, grape juice and wine. Sensing performances are discussed in terms of calibration plot and limit of detection.

Preparation of Functionalized Diorganomagnesium Reagents in Toluene via Bromine or Iodine/Magnesium-Exchange Reactions

Synthesis ◽  
2021 ◽  
Author(s):  
Alexandre Desaintjean ◽  
Fanny Danton ◽  
Paul Knochel
Keyword(s):  
Exchange Reaction ◽  
Nitro Group ◽  
General Formula ◽  
Functional Groups ◽  
Exchange Reactions ◽  
Acyl Chlorides ◽  
Aryl Iodides ◽  
Highly Sensitive ◽  
Wide Range ◽  
Magnesium Exchange

A wide range of polyfunctionalized di(hetero)aryl- and dialkenyl-magnesium reagents were prepared in toluene within 10 to 120 min between −78 °C and 25 °C via an I/Mg- or Br/Mg-exchange reaction using reagents of the general formula R2Mg (R = sBu, Mes). Highly sensitive functional groups, such as a triazene or a nitro group, were tolerated in these exchange reactions, enabling the synthesis of various functionalized (hetero)arenes and alkenes derivatives after quenching with several electrophiles including allyl bromides, acyl chlorides, aldehydes, ketones, and aryl iodides.

scholarly journals 6-Axis Stress Tensor Sensor Using Multifaceted Silicon Piezoresistors

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 279
Author(s):  
Kentaro Noda ◽  
Jian Sun ◽  
Isao Shimoyama
Keyword(s):  
Stress Tensor ◽  
Elastic Body ◽  
Building Materials ◽  
Sensor Response ◽  
Stress Change ◽  
Sensor Chip ◽  
Naked Eye ◽  
Highly Sensitive ◽  
Wide Range

A tensor sensor can be used to measure deformations in an object that are not visible to the naked eye by detecting the stress change inside the object. Such sensors have a wide range of application. For example, a tensor sensor can be used to predict fatigue in building materials by detecting the stress change inside the materials, thereby preventing accidents. In this case, a sensor of small size that can measure all nine components of the tensor is required. In this study, a tensor sensor consisting of highly sensitive piezoresistive beams and a cantilever to measure all of the tensor components was developed using MEMS processes. The designed sensor had dimensions of 2.0 mm by 2.0 mm by 0.3 mm (length by width by thickness). The sensor chip was embedded in a 15 mm3 cubic polydimethylsiloxane (PDMS) (polydimethylsiloxane) elastic body and then calibrated to verify the sensor response to the stress tensor. We demonstrated that 6-axis normal and shear Cauchy stresses with 5 kPa in magnitudes can be measured by using the fabricated sensor.

scholarly journals Formation of Carbon Quantum Dots via Hydrothermal Carbonization: Investigate the Effect of Precursors

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 986
Author(s):  
Md Rifat Hasan ◽  
Nepu Saha ◽  
Thomas Quaid ◽  
M. Toufiq Reza
Keyword(s):  
Quantum Dots ◽  
Optical Properties ◽  
Microcrystalline Cellulose ◽  
Uv Light ◽  
Synthesis Method ◽  
Hydrothermal Carbonization ◽  
Carbon Quantum Dots ◽  
Medical Diagnostics ◽  
Particle Size Range ◽  
Wide Range

Carbon quantum dots (CQDs) are nanomaterials with a particle size range of 2 to 10 nm. CQDs have a wide range of applications such as medical diagnostics, bio-imaging, biosensors, coatings, solar cells, and photocatalysis. Although the effect of various experimental parameters, such as the synthesis method, reaction time, etc., have been investigated, the effect of different feedstocks on CQDs has not been studied yet. In this study, CQDs were synthesized from hydroxymethylfurfural, furfural, and microcrystalline cellulose via hydrothermal carbonization at 220 °C for 30 min of residence time. The produced CQDs showed green luminescence behavior under the short-wavelength UV light. Furthermore, the optical properties of CQDs were investigated using ultraviolet-visible spectroscopy and emission spectrophotometer, while the morphology and chemical bonds of CQDs were investigated using transmission electron microscopy and Fourier-transform infrared spectroscopy, respectively. Results showed that all CQDs produced from various precursors have absorption and emission properties but these optical properties are highly dependent on the type of precursor. For instance, the mean particle sizes were 6.36 ± 0.54, 5.35 ± 0.56, and 3.94 ± 0.60 nm for the synthesized CQDs from microcrystalline cellulose, hydroxymethylfurfural, and furfural, respectively, which appeared to have similar trends in emission intensities. In addition, the synthesized CQDs experienced different functionality (e.g., C=O, O-H, C-O) resulting in different absorption behavior.

scholarly journals State of the Science in Dried Blood Spots

2018 ◽  
Vol 64 (4) ◽  
pp. 656-679 ◽  
Author(s):  
Jeffrey D Freeman ◽  
Lori M Rosman ◽  
Jeremy D Ratcliff ◽  
Paul T Strickland ◽  
David R Graham ◽  
...  
Keyword(s):  
Systematic Approach ◽  
Full Range ◽  
Dried Blood Spots ◽  
Blood Spots ◽  
Highly Sensitive ◽  
Wide Range ◽  
Potential Applications ◽  
Review Of Reviews ◽  
Near Term ◽  
State Of The Science

Abstract BACKGROUND Advancements in the quality and availability of highly sensitive analytical instrumentation and methodologies have led to increased interest in the use of microsamples. Among microsamples, dried blood spots (DBS) are the most well-known. Although there have been a variety of review papers published on DBS, there has been no attempt at describing the full range of analytes measurable in DBS, or any systematic approach published for characterizing the strengths and weaknesses associated with adoption of DBS analyses. CONTENT A scoping review of reviews methodology was used for characterizing the state of the science in DBS. We identified 2018 analytes measured in DBS and found every common analytic method applied to traditional liquid samples had been applied to DBS samples. Analytes covered a broad range of biomarkers that included genes, transcripts, proteins, and metabolites. Strengths of DBS enable its application in most clinical and laboratory settings, and the removal of phlebotomy and the need for refrigeration have expanded biosampling to hard-to-reach and vulnerable populations. Weaknesses may limit adoption in the near term because DBS is a nontraditional sample often requiring conversion of measurements to plasma or serum values. Opportunities presented by novel methodologies may obviate many of the current limitations, but threats around the ethical use of residual samples must be considered by potential adopters. SUMMARY DBS provide a wide range of potential applications that extend beyond the reach of traditional samples. Current limitations are serious but not intractable. Technological advancements will likely continue to minimize constraints around DBS adoption.

A new DNA sensor design for the simultaneous detection of HPV type 16 and 18 DNA

2018 ◽  
Vol 265 ◽  
pp. 514-521 ◽  
Author(s):  
Sakda Jampasa ◽  
Weena Siangproh ◽  
Rawiwan Laocharoensuk ◽  
Pattamawadee Yanatatsaneejit ◽  
Tirayut Vilaivan ◽  
...  
Keyword(s):  
Simultaneous Detection ◽  
Sensor Design ◽  
Dna Sensor

scholarly journals Multi-Quantum Dots-Embedded Silica-Encapsulated Nanoparticle-Based Lateral Flow Assay for Highly Sensitive Exosome Detection

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 768
Author(s):  
Hyung-Mo Kim ◽  
Chiwoo Oh ◽  
Jaehyun An ◽  
Seungki Baek ◽  
Sungje Bock ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Limit Of Detection ◽  
Specific Binding ◽  
Calf Serum ◽  
Lateral Flow ◽  
Lateral Flow Immunoassay ◽  
Uniform Size ◽  
Highly Sensitive ◽  
Wide Range ◽  
New Biomarkers

Exosomes are attracting attention as new biomarkers for monitoring the diagnosis and prognosis of certain diseases. Colorimetric-based lateral-flow assays have been previously used to detect exosomes, but these have the disadvantage of a high limit of detection. Here, we introduce a new technique to improve exosome detection. In our approach, highly bright multi-quantum dots embedded in silica-encapsulated nanoparticles (M–QD–SNs), which have uniform size and are brighter than single quantum dots, were applied to the lateral flow immunoassay method to sensitively detect exosomes. Anti-CD63 antibodies were introduced on the surface of the M–QD–SNs, and a lateral flow immunoassay with the M–QD–SNs was conducted to detect human foreskin fibroblast (HFF) exosomes. Exosome samples included a wide range of concentrations from 100 to 1000 exosomes/µL, and the detection limit of our newly designed system was 117.94 exosome/μL, which was 11 times lower than the previously reported limits. Additionally, exosomes were selectively detected relative to the negative controls, liposomes, and newborn calf serum, confirming that this method prevented non-specific binding. Thus, our study demonstrates that highly sensitive and quantitative exosome detection can be conducted quickly and accurately by using lateral immunochromatographic analysis with M–QD–SNs.

Highly Sensitive and Wide Range Non-Enzymatic Electrochemical Detection of Cholesterol using Pencil Lead Electrodes

2021 ◽  
Author(s):  
Navaneeth Punnakkal ◽  
Jeethu Raveendran ◽  
Suneesh Punathil Vasu ◽  
Bipin G Nair ◽  
T G Satheesh Babu
Keyword(s):  
Electrochemical Detection ◽  
Highly Sensitive ◽  
Wide Range ◽  
Lead Electrodes ◽  
Pencil Lead
Sign in / Sign up

Export Citation Format

Share Document