scholarly journals Optical decomposition of DNA gel and modification of object mobility on micrometre scale

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Suguru Shimomura ◽  
Takahiro Nishimura ◽  
Yusuke Ogura ◽  
Jun Tanida
Keyword(s):  
Thermal Energy ◽  
Dna Sequences ◽  
Biomedical Applications ◽  
State Transitions ◽  
Dye Molecules ◽  
Radiative Relaxation ◽  
Polystyrene Beads ◽  
Object Mobility ◽  
Detection Of Biomolecules ◽  
Viscosity Changes

AbstractDNA gels can be engineered to exhibit specific properties through the choice of DNA sequences and modification with dye molecules, and can therefore be useful in biomedical applications such as the detection of biomolecules. State transitions of DNA gels on the micrometre scale can generate a viscosity gradient, which can be used to modify the mobility of micrometre-sized objects. In this paper, we propose a method for changing the viscosity of DNA gels using optical decomposition. The use of light allows for decomposition on the micrometre scale, which can be used to achieve patterned viscosity changes within DNA gels. Decomposition was induced by thermal energy released through non-radiative relaxation of excited quenchers. We demonstrated the decomposition of DNA gels in response to irradiation patterns on the micrometre scale. In addition, as a result of changes in DNA gel viscosity due to decomposition, the mobility of polystyrene beads was shown to increase. This technique could provide a new optical approach for controlling the mobility of micrometre-sized objects.

scholarly journals Interfacing aptamers, nanoparticles and graphene in a hierarchical structure for highly selective detection of biomolecules in OECT devices

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Carlotta Peruzzi ◽  
Silvia Battistoni ◽  
Daniela Montesarchio ◽  
Matteo Cocuzza ◽  
Simone Luigi Marasso ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Au Nanoparticles ◽  
Limit Of Detection ◽  
High Sensitivity ◽  
Minimal Invasiveness ◽  
Hierarchic Structure ◽  
Final Response ◽  
Detection Of Biomolecules ◽  
Good Signal ◽  
Detection Of Biomarkers

AbstractIn several biomedical applications, the detection of biomarkers demands high sensitivity, selectivity and easy-to-use devices. Organic electrochemical transistors (OECTs) represent a promising class of devices combining a minimal invasiveness and good signal transduction. However, OECTs lack of intrinsic selectivity that should be implemented by specific approaches to make them well suitable for biomedical applications. Here, we report on a biosensor in which selectivity and a high sensitivity are achieved by interfacing, in an OECT architecture, a novel gate electrode based on aptamers, Au nanoparticles and graphene hierarchically organized to optimize the final response. The fabricated biosensor performs state of the art limit of detection monitoring biomolecules, such as thrombin-with a limit of detection in the picomolar range (≤ 5 pM) and a very good selectivity even in presence of supraphysiological concentrations of Bovine Serum Albumin (BSA-1mM). These accomplishments are the final result of the gate hierarchic structure that reduces sterich indrance that could contrast the recognition events and minimizes false positive, because of the low affinity of graphene towards the physiological environment. Since our approach can be easily applied to a large variety of different biomarkers, we envisage a relevant potential for a large series of different biomedical applications.

Expected frequencies of DNA patterns using whittle's formula

1991 ◽  
Vol 28 (04) ◽  
pp. 886-892 ◽  
Author(s):  
Richard Cowan
Keyword(s):  
Markov Chain ◽  
Molecular Biology ◽  
Dna Sequences ◽  
Exact Method ◽  
State Transitions ◽  
Initial State ◽  
Expected Frequency

Given a realisation of a Markov chain, one can count the numbers of state transitions of each type. One can ask how many realisations are there with these transition counts and the same initial state. Whittle (1955) has answered this question, by finding an explicit though complicated formula, and has also shown that each realisation is equally likely. In the analysis of DNA sequences which comprise letters from the set {A, C, G, T}, it is often useful to count the frequency of a pattern, say ACGCT, in a long sequence and compare this with the expected frequency for all sequences having the same start letter and the same transition counts (or ‘dinucleotide counts' as they are called in the molecular biology literature). To date, no exact method exists; this paper rectifies that deficiency.

Investigation of Energy Transfer between CdTe Nanocrystals on Polystyrene Beads and Dye Molecules for FRET-SNOM Applications†

2004 ◽  
Vol 108 (38) ◽  
pp. 14527-14534 ◽  
Author(s):  
Felix Müller ◽  
Stephan Götzinger ◽  
Nikolai Gaponik ◽  
Horst Weller ◽  
Jürgen Mlynek ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Dye Molecules ◽  
Polystyrene Beads ◽  
Cdte Nanocrystals

scholarly journals Development of MoSe2 Nano-Urchins as a Sensing Platform for a Selective Bio-Capturing of Escherichia. coli Shiga Toxin DNA

Biosensors ◽  
2018 ◽  
Vol 8 (3) ◽  
pp. 77 ◽  
Author(s):  
Jagriti Narang ◽  
Annu Mishra ◽  
Roberto Pilloton ◽  
Alekhya VV ◽  
Shikha Wadhwa ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Dna Sequences ◽  
Shiga Toxin ◽  
Fourier Transforms ◽  
Glass Electrode ◽  
Oxide Glass ◽  
Current Response ◽  
Detection Range ◽  
Sensing Platform ◽  
Detection Of Biomolecules

The present study was aimed to develop “fluorine doped” tin oxide glass electrode with a MoSe2 nano-urchin based electrochemical biosensor for detection of Escherichia. coli Shiga toxin DNA. The study comprises two conductive electrodes, and the working electrodes were drop deposited using MoSe2 nano-urchin, and DNA sequences specific to Shiga toxin Escherichia. coli. Morphological characterizations were performed using Fourier transforms infrared spectrophotometer; X-ray diffraction technique and scanning electron microscopy. All measurements were done using methylene blue as an electrochemical indicator. The proposed electrochemical geno-sensor showed good linear detection range of 1 fM–100 μM with a low detection limit of 1 fM where the current response increased linearly with Escherichia. coli Shiga toxin dsDNA concentration with R2 = 0.99. Additionally, the real sample was spiked with the dsDNA that shows insignificant interference. The results revealed that the developed sensing platform significantly improved the sensitivity and can provide a promising platform for effective detection of biomolecules using minute samples due to its stability and sensitivity.

Expected frequencies of DNA patterns using whittle's formula

1991 ◽  
Vol 28 (4) ◽  
pp. 886-892 ◽  
Author(s):  
Richard Cowan
Keyword(s):  
Markov Chain ◽  
Molecular Biology ◽  
Dna Sequences ◽  
Exact Method ◽  
State Transitions ◽  
Initial State ◽  
Expected Frequency

Given a realisation of a Markov chain, one can count the numbers of state transitions of each type. One can ask how many realisations are there with these transition counts and the same initial state. Whittle (1955) has answered this question, by finding an explicit though complicated formula, and has also shown that each realisation is equally likely. In the analysis of DNA sequences which comprise letters from the set {A, C, G, T}, it is often useful to count the frequency of a pattern, say ACGCT, in a long sequence and compare this with the expected frequency for all sequences having the same start letter and the same transition counts (or ‘dinucleotide counts' as they are called in the molecular biology literature). To date, no exact method exists; this paper rectifies that deficiency.

scholarly journals Improvements in Gene Editing Technology Boost Its Applications in Livestock

2021 ◽  
Vol 11 ◽  
Author(s):  
Iuri Viotti Perisse ◽  
Zhiqiang Fan ◽  
Galina N. Singina ◽  
Kenneth L. White ◽  
Irina A. Polejaeva
Keyword(s):  
Genome Editing ◽  
Dna Sequences ◽  
Nuclear Transfer ◽  
Biomedical Applications ◽  
Gene Editing ◽  
Farm Animals ◽  
Primary Methods ◽  
Base Editing ◽  
Advantages And Disadvantages ◽  
Transitions And Transversions

Accelerated development of novel CRISPR/Cas9-based genome editing techniques provides a feasible approach to introduce a variety of precise modifications in the mammalian genome, including introduction of multiple edits simultaneously, efficient insertion of long DNA sequences into specific targeted loci as well as performing nucleotide transitions and transversions. Thus, the CRISPR/Cas9 tool has become the method of choice for introducing genome alterations in livestock species. The list of new CRISPR/Cas9-based genome editing tools is constantly expanding. Here, we discuss the methods developed to improve efficiency and specificity of gene editing tools as well as approaches that can be employed for gene regulation, base editing, and epigenetic modifications. Additionally, advantages and disadvantages of two primary methods used for the production of gene-edited farm animals: somatic cell nuclear transfer (SCNT or cloning) and zygote manipulations will be discussed. Furthermore, we will review agricultural and biomedical applications of gene editing technology.

Applications of Scanning Microscopy in Biomedical Research

1968 ◽  
Vol 26 ◽  
pp. 354-355
Author(s):  
T. L. Hayes
Keyword(s):  
Information Content ◽  
Biomedical Research ◽  
Biomedical Applications ◽  
Three Dimensional ◽  
Dental Enamel ◽  
Resolving Power ◽  
Whole Mount ◽  
Two Parameters ◽  
Content Information ◽  
Sectioned Tissue

Biomedical applications of the scanning electron microscope (SEM) have increased in number quite rapidly over the last several years. Studies have been made of cells, whole mount tissue, sectioned tissue, particles, human chromosomes, microorganisms, dental enamel and skeletal material. Many of the advantages of using this instrument for such investigations come from its ability to produce images that are high in information content. Information about the chemical make-up of the specimen, its electrical properties and its three dimensional architecture all may be represented in such images. Since the biological system is distinctive in its chemistry and often spatially scaled to the resolving power of the SEM, these images are particularly useful in biomedical research.In any form of microscopy there are two parameters that together determine the usefulness of the image. One parameter is the size of the volume being studied or resolving power of the instrument and the other is the amount of information about this volume that is displayed in the image. Both parameters are important in describing the performance of a microscope. The light microscope image, for example, is rich in information content (chemical, spatial, living specimen, etc.) but is very limited in resolving power.

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