ORIENTATING MANIPULATION OF CYLINDRICAL PARTICLES WITH OPTICAL TWEEZERS

2008 ◽  
Vol 17 (04) ◽  
pp. 387-394 ◽  
Author(s):  
XIUDONG SUN ◽  
XUECONG LI ◽  
JIANLONG ZHANG
Keyword(s):  
Escherichia Coli ◽  
Carbon Nanotubes ◽  
Laser Beam ◽  
Optical Tweezers ◽  
Optical Trap ◽  
Polarization Direction ◽  
Beam Shape ◽  
E Coli ◽  
Potential Applications ◽  
Cylindrical Particles

Orientating manipulations of cylindrical particles were performed by optical tweezers. Vertical and horizontal manipulations of Escherichia coli (E. coli) were carried out by changing the trapping depth and the focused laser beam shape. It was found that carbon nanotubes bundles (CNTBs) could be rotated in the linear polarized optical trap until it orientated its long axis along the linear polarization direction of the laser beam. However, E.coli could not be orientated in this way. Corresponding mechanisms were discussed based on the anisomeric electric characters of CNTBs. These orientation technologies of cylindrical objects with optical trap have potential applications in assembling nano-electric devices.

scholarly journals DNA-FACE™ - An Escherichia coli-based DNA Amplification-Expression Technology for Automatic Assembly of Concatemeric ORFs and Proteins

2021 ◽  
Author(s):  
Piotr M. Skowron ◽  
Agnieszka Zylicz-Stachula
Keyword(s):  
Escherichia Coli ◽  
Animal Studies ◽  
Immunological Response ◽  
Dna Amplification ◽  
Open Reading Frames ◽  
Biological Drugs ◽  
E Coli ◽  
Potential Applications ◽  
Dna Fragment ◽  
High Level

DNA-FACE™ (DNA Fragment Amplification & Concatemeric Expressed Nucleic Acids and Proteins) is a universal biotechnological platform, developed as Escherichia coli (E. coli) system. It is based on the ordered, head-to-tail directional ligation of the amplified DNA fragments. The technology enables the construction of targeted biomolecules - genetically programmed, concatemeric DNA, RNA, and proteins, designed to fit a particular task. The constructed, “artificial” (never seen in Nature) tandem repeat macromolecules, with specialized functions, may contain up to 500 copies of monomeric units. The technology greatly exceeds the current capabilities of chemical gene synthesis. The vector-enzymatic DNA fragment amplification assembles the DNA segments, forming continuous Open Reading Frames (ORFs). The obtained ORFs are ready for high-level expression in E. coli without a need for subcloning. The presented method has potential applications in pharmaceutical industry and tissue engineering, including vaccines, biological drugs, drug delivery systems, mass-production of peptide-derived biomaterials, industrial and environmental processes. The technology has been patented worldwide and used successfully in the construction of anti-HBV vaccines, pro-regenerative biological drugs and, recently, the anti-SARS-CoV-2 vaccine. The anti-SARS-CoV-2 vaccine, developed using the DNA-FACE™ technology, is nontoxic and induces strong immunological response to recombinant human spike and nucleocapsid proteins, as shown in animal studies.

Red blood cell in the field of a beam of optical tweezers

2022 ◽  
Vol 52 (1) ◽  
pp. 22-27
Author(s):  
P B Ermolinskiy ◽  
A E Lugovtsov ◽  
A N Semenov ◽  
A V Priezzhev
Keyword(s):  
Blood Cell ◽  
Laser Beam ◽  
Red Blood Cells ◽  
Optical Tweezers ◽  
Red Blood Cell ◽  
Blood Cells ◽  
Optical Trapping ◽  
Optical Trap ◽  
Beam Power ◽  
Deformation Properties

Abstract We consider the effect of a tightly focused laser beam with a wavelength of 1064 nm and a power from 10 to 160 mW on red blood cells during their optical trapping with optical tweezers. It is found that the shape of a red blood cell, which alters after optical trapping, ceases to change when the trapping duration is less than 5 min and the laser beam power is less than 60 mW. At a beam power above 80 mW, the red blood cell begins to fold at a trapping duration of about 1 min, and at powers above 100-150 mW, the red blood cell membrane ruptures in 1-3 min after optical trapping. It is also found that with repeated short-term capture of a red blood cell in an optical trap, the deformation properties of the membrane change: it becomes more rigid. The obtained results are important both for understanding the mechanisms of interaction of a laser beam with red blood cells and for optimising the technique of optical experiments, especially for measuring the deformation properties of a membrane using optical tweezers.

scholarly journals Optical Tweezers Cause Physiological Damage to Escherichia coli and Listeria Bacteria

2008 ◽  
Vol 74 (8) ◽  
pp. 2441-2446 ◽  
Author(s):  
M. B. Rasmussen ◽  
L. B. Oddershede ◽  
H. Siegumfeldt
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Listeria Monocytogenes ◽  
Optical Tweezers ◽  
Laser Power ◽  
Fluorescent Protein ◽  
Growth Conditions ◽  
Ph Gradient ◽  
Bacterial Cells ◽  
E Coli

ABSTRACT We investigated the degree of physiological damage to bacterial cells caused by optical trapping using a 1,064-nm laser. The physiological condition of the cells was determined by their ability to maintain a pH gradient across the cell wall; healthy cells are able to maintain a pH gradient over the cell wall, whereas compromised cells are less efficient, thus giving rise to a diminished pH gradient. The pH gradient was measured by fluorescence ratio imaging microscopy by incorporating a pH-sensitive fluorescent probe, green fluorescent protein or 5(6)-carboxyfluorescein diacetate succinimidyl ester, inside the bacterial cells. We used the gram-negative species Escherichia coli and three gram-positive species, Listeria monocytogenes, Listeria innocua, and Bacillus subtilis. All cells exhibited some degree of physiological damage, but optically trapped E. coli and L. innocua cells and a subpopulation of L. monocytogenes cells, all grown with shaking, showed only a small decrease in pH gradient across the cell wall when trapped by 6 mW of laser power for 60 min. However, another subpopulation of Listeria monocytogenes cells exhibited signs of physiological damage even while trapped at 6 mW, as did B. subtilis cells. Increasing the laser power to 18 mW caused the pH gradient of both Listeria and E. coli cells to decrease within minutes. Moreover, both species of Listeria exhibited more-pronounced physiological damage when grown without shaking than was seen in cells grown with shaking, and the degree of damage is therefore also dependent on the growth conditions.

One-step synthesis of Ag–reduced graphene oxide–multiwalled carbon nanotubes for enhanced antibacterial activities

2015 ◽  
Vol 39 (6) ◽  
pp. 4583-4590 ◽  
Author(s):  
Leila Shahriary ◽  
Roopa Nair ◽  
Sushma Sabharwal ◽  
Anjali A. Athawale
Keyword(s):  
Escherichia Coli ◽  
Carbon Nanotubes ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Multiwalled Carbon Nanotubes ◽  
Antibacterial Activities ◽  
Multiwalled Carbon ◽  
E Coli ◽  
Reduced Graphene ◽  
One Step

A silver nanoparticles decorated reduced graphene oxide–multiwalled carbon nanotubes (Ag–rGO–MWCNTs) hybrid exhibits an excellent antibacterial activity against Escherichia coli (E. coli).

scholarly journals Evaluation of three different vectors on human iLRP expression in Escherichia coli

2019 ◽  
Author(s):  
Bainan Liu ◽  
Dong Zhang ◽  
Lingli Yan ◽  
Ming Zhou
Keyword(s):  
Escherichia Coli ◽  
Human Cancer ◽  
Bacterial Genome ◽  
Laminin Receptor ◽  
Receptor Protein ◽  
Expression Vectors ◽  
E Coli ◽  
Human Cancer Cells ◽  
Good Target ◽  
Potential Applications

Abstract Background: iLRP (immature laminin receptor protein) is a tumor associated antigen over-expressed on the surface of most human cancer cells and plays an important role in the process of tumorigenesis and development. It has strong auto-immunogenicity in patients and is a good target protein for tumor immunotherapy. The aim of this study is to find a practical and an efficient method for the production of recombinant iLRP, and to provide enough recombinant protein for further study of its potential applications.Results: In this report, three different expression vectors based on pET-30a(+) from pET expression systems were constructed. The first one is to add a 6xHis-Tag to the N-terminal of natural iLRP, which is called as pET-His-iLRP. The second one is to include an S-Tag between the C-terminal of 6xHis-Tag and the N-terminal of natural iLRP, which is called as pET-His-S-iLRP. The third one only contains the 6xHis-Tag in front of the N-terminal of iLRP, but the natural iLRP gene was first optimized according to the bacterial genome, and the constructed vector was named as pET-His-Opt-iLRP. Then the expression of three vectors in Escherichia coli (E. coli) BL21 (DE3) was analyzed. Results demonstrated that the expression of iLRP was the highest in the vector of pET-His-Opt-iLRP, followed by the vector of pET-His-S-iLRP, and the vector of pET-His-iLRP expressed the lowest iLRP.Conclusions: According to the results, it was concluded that the vetor pET-His-Opt-iLRP combining the codon-optimized iLRP gene with a 6xHis-Tag had the best effect on the expression of iLRP, and the expression in vectors with the natural iLRP gene depends on its leader sequences in the expression frame. The longer leader sequences accommodate to the host E. coli, the higher expression the engineered gene would be.

scholarly journals Synthesis of nanocomposites of polypyrrole/carbon nanotubes/silver nano particles and their application in water disinfection

RSC Advances ◽  
2017 ◽  
Vol 7 (27) ◽  
pp. 16878-16884 ◽  
Author(s):  
Mohamed Abdel Salam ◽  
Abdullah Y. Obaid ◽  
Reda M. El-Shishtawy ◽  
Saleh A. Mohamed
Keyword(s):  
Escherichia Coli ◽  
Carbon Nanotubes ◽  
Staphylococcus Aureus ◽  
Global Health ◽  
Health Problem ◽  
Pathogenic Bacteria ◽  
Water Disinfection ◽  
Nano Particles ◽  
E Coli ◽  
Global Health Problem

Contamination of drinking or irrigation water with pathogenic bacteria, such as Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), is a major global health problem.

scholarly journals Manipulating rod-shaped bacteria with optical tweezers

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Zheng Zhang ◽  
Tom E. P. Kimkes ◽  
Matthias Heinemann
Keyword(s):  
Escherichia Coli ◽  
Optical Tweezers ◽  
Oscillation Frequency ◽  
Flow Direction ◽  
Single Cells ◽  
Cell Length ◽  
E Coli ◽  
Upper Limits ◽  
Medium Flow

AbstractOptical tweezers have great potential in microbiology for holding and manipulating single cells under a microscope. However, the methodology to use optical tweezers for live cell studies is still at its infancy. In this work, we determined suitable parameters for stable trapping of single Escherichia coli bacteria, and identified the upper limits of IR-exposure that can be applied without affecting viability. We found that the maximum tolerable IR-exposure is 2.5-fold higher when employing oscillating instead of stationary optical trapping (20 J and 8 J, respectively). We found that good stability of cells in an oscillating trap is achieved when the effective trap length is 20% larger than the cell length, the oscillation frequency higher than 100 Hz and the trap oriented perpendicular to the medium flow direction. Further, we show, using an IR power just sufficient for stable holding, that bacteria remain viable during at least 30 min of holding in an oscillating trap. In this work, we established a method for long-term stable handling of single E. coli cells using optical tweezers. This work will pave the way for future use of optical tweezers in microbiology.

scholarly journals Effect of multi-walled carbon nanotubes on Escherichia coli biofilm formation

2021 ◽  
pp. 87-92
Author(s):  
Yu. G. Maksimova ◽  
◽  
Ya. E. Bykova ◽  
◽  
Keyword(s):  
Escherichia Coli ◽  
Carbon Nanotubes ◽  
Biofilm Formation ◽  
Culture Medium ◽  
Nano Materials ◽  
E Coli ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Different Sources ◽  
Degree Of Purification

The effect of purified and unpurified multi-walled carbon nanotubes on the biofilm formation of Esche-richia coli strains isolated from different sources has been studied. It has been shown that carbon nano-materials in the culture medium do not inhibit biofilm formation, but on days 1–3 of growth lead to the formation of more massive biofilms of some strains. Significantly more intense destruction of mature bio-films of E. coli K12, E. coli K12 TG1 (pXen7) and one natural strain in the presence of carbon nanotubes in the medium was noted. No clear dependence of biofilm formation and destruction of formed biofilms on the degree of purification of nanotubes was found.

Optical tweezers: 20 years on

2006 ◽  
Vol 364 (1849) ◽  
pp. 3521-3537 ◽  
Author(s):  
David McGloin
Keyword(s):  
Laser Beam ◽  
Recent Work ◽  
Optical Tweezers ◽  
Optical Trap ◽  
Critical Discussion ◽  
Optical Manipulation ◽  
Gradient Force ◽  
Seminal Paper ◽  
Single Beam ◽  
Dielectric Particles

In 1986, Arthur Ashkin and colleagues published a seminal paper in Optics Letters , ‘Observation of a single-beam gradient force optical trap for dielectric particles’ which outlined a technique for trapping micrometre-sized dielectric particles using a focused laser beam, a technology which is now termed optical tweezers. This paper will provide a background in optical manipulation technologies and an overview of the applications of optical tweezers. It contains some recent work on the optical manipulation of aerosols and concludes with a critical discussion of where the future might lead this maturing technology.

Sites of Adsorption of the Bacteriophages T3 and T5 on the Wall of Escherichia Coli B.

1967 ◽  
Vol 25 ◽  
pp. 96-97
Author(s):  
Manfred E. Bayer
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Electron Microscope ◽  
Uranyl Acetate ◽  
E Coli ◽  
Receptor Sites ◽  
Rigid Cell Wall ◽  
Host Cell Surface ◽  
Bacterial Viruses ◽  
Escherichia Coli B

Bacterial viruses adsorb specifically to receptors on the host cell surface. Although the chemical composition of some of the cell wall receptors for bacteriophages of the T-series has been described and the number of receptor sites has been estimated to be 150 to 300 per E. coli cell, the localization of the sites on the bacterial wall has been unknown.When logarithmically growing cells of E. coli are transferred into a medium containing 20% sucrose, the cells plasmolize: the protoplast shrinks and becomes separated from the somewhat rigid cell wall. When these cells are fixed in 8% Formaldehyde, post-fixed in OsO4/uranyl acetate, embedded in Vestopal W, then cut in an ultramicrotome and observed with the electron microscope, the separation of protoplast and wall becomes clearly visible, (Fig. 1, 2). At a number of locations however, the protoplasmic membrane adheres to the wall even under the considerable pull of the shrinking protoplast. Thus numerous connecting bridges are maintained between protoplast and cell wall. Estimations of the total number of such wall/membrane associations yield a number of about 300 per cell.

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