scholarly journals Electrospun Three-Dimensional Nanofibrous Structure via Probe Arrays Inducing

Micromachines ◽  
2018 ◽  
Vol 9 (9) ◽  
pp. 427 ◽  
Author(s):  
Yifang Liu ◽  
Ruimin Liu ◽  
Xiang Wang ◽  
Jiaxin Jiang ◽  
Wenwang Li ◽  
...  
Keyword(s):  
Flow Rate ◽  
Applied Voltage ◽  
3D Structure ◽  
Three Dimensional ◽  
Development Trend ◽  
Processing Parameters ◽  
Industrial Applications ◽  
Nano Fabrication ◽  
Direct Printing ◽  
Deposition Area

The fast and precise direct-printing of micro three-dimensional (3D) structures is the important development trend for micro/nano fabrication technique. A novel method with probe arrays was built up to realize the controllable deposition of 3D electrospun nanofibrous structures. Firstly, several 3D nanofibrous structures were built on a single probe and 2-, 3-probes, which indicated that the probe height and probe interval played a key role on the 3D structure morphology. Then, different stereo nanofibrous structures based on multiprobe arrays were achieved accurately and the effects of processing parameters, including the probe height, probe interval, applied voltage and flow rate on the deposition behaviors of electrospun nanofiber over the probe arrays were investigated. The deposition area of 3D electrospun nanofibrous structures decreased with the increase of probe interval, applied voltage, and flow rate. Several 3D nanofibrous structures of special shapes including convex, triangle wave, inverted cone and complex curved surface were demonstrated by controlling the configuration of probe arrays and electrospinning parameters. This work provides an effective and simple way for the construction of 3D electrospun nanofibrous structures, which has great potentials in various medical and industrial applications.

On the 3D Structure of Elasticity-Induced Unstable Flow in the Curved Microchannel by Using Confocal Micro-PIV and Polarized Camera

2015 ◽  
Author(s):  
Xiao-Bin Li ◽  
Masamichi Oishi ◽  
Marie Oshima ◽  
Feng-Chen Li ◽  
Song-Jing Li
Keyword(s):  
Flow Rate ◽  
High Speed ◽  
3D Structure ◽  
Three Dimensional ◽  
Working Fluid ◽  
Wall Region ◽  
Unstable Flow ◽  
Solution Flow ◽  
Micro Particle Image Velocimetry ◽  
Micro Piv

In this paper, the three-dimensional (3D) structures of a micellar solution flow in the curvilinear microchannel have been investigated by means of confocal micro particle image velocimetry (PIV). The working fluid is aqueous solution of CTAC/NaSal (cetyltrimethylammonium / Sodium Salysilate). As the flow rate increases, the flow gradually gets into the irregular motion. It is found that the inside flow seems not completely chaotic, but in a manner of oscillation. To be specific, the flow nonlinearity grows as the flow rate increases, the inside flow shows different structures near the wall region and in the bulk due to the elongation of viscoelastic surfactant. Typically, two sub-streams were twisted together, and their flow directions change at the locations where the signs of geometric curvature change. The oscillation stripes represented the area of high extensional stress in the viscoelastic fluid, and were further identified by using polarized high-speed camera. Moreover, statistics shows that the viscoelastic flow field inside the curved microchannel shares the main features of elastic turbulence.

scholarly journals TAYLOR CONE–JET MODE IN THE FABRICATION OF ELECTROSPRAYED MICROSPHERES

2018 ◽  
Vol 55 (1B) ◽  
pp. 216 ◽  
Author(s):  
Viet Linh Nguyen - Vu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Polymer Solution ◽  
Flow Rate ◽  
Applied Voltage ◽  
Processing Parameters ◽  
Taylor Cone ◽  
Sem Micrographs ◽  
Scanning Electron

In this study, electrospray modes were investigated to clarify their effects on the morphology and size of polycaprolactone (PCL) particles. The result indicated that electrosprayed microspheres with homogeneous and stable morphology were fabricated by using cone–jet mode and suitable electrospray processing parameters. Besides, the PCL solution was created by dissolving in dichloromethane with different concentrations such as 3.5%, 4%, 4.5% and 5%. The scanning electron microscopy (SEM) micrographs pointed that electrosprayed PCL microspheres were formed by using 4.5 % polymer solution. In addition, the reproducible and homogeneous morphology of PCL microparticles were obtained at the following set of parameters: applied voltage of 18 kV, flow rate of 1.5 mL/h and distance tip to collector of 20 cm. Moreover, at the collecting distance of 15–25 cm, the flow rate of 1.2–1.8 mL/h and applied voltage of 18 kV the cone–jet mode was generated. It was an effective electrospray mode to create stable and homogeneous microspheres.

scholarly journals Effect of parameters on the morphology and fibre diameters of edible electrospun chitosan-cellulose acetate-gelatin hybrid nanofibres

2018 ◽  
Vol 192 ◽  
pp. 03038
Author(s):  
Jaruayporn Somsap ◽  
Kobsak Kanjanapongkul ◽  
Racha Tepsorn
Keyword(s):  
Cellulose Acetate ◽  
Flow Rate ◽  
Applied Voltage ◽  
Acetic Acid Solution ◽  
Volume Ratio ◽  
Solution Concentration ◽  
Processing Parameters ◽  
Gelatin Solution ◽  
Electrospun Nanofibres ◽  
Scanning Electron

Electrospinning is the favorite process to fabricate fibres with diameter in the range nanoscale through the action of electric field. In this study, 3-7% chitosan, 18.0% cellulose acetate and 30.0% gelatin solution in aqueous 80% acetic acid solution were blended at the volume ratio of 4:1:5 have been successfully electrospun. The effect of processing parameters and the concentration of the polymer solution on the morphology and diameter of electrospun were investigated. The morphology and diameter of electrospun fibres were observed by scanning electron microscope. The diameters of chitosan-cellulose acetate-gelatin nanofibres ranging from 78.94 to 421.05 nm. The results showed that the fibre diameters increased when the solution concentration and flow rate were increased, whereas the fibre diameters decreased when the applied voltage and distance between tip to collector were increased. The conditions of the solution concentration 18.8 %wt, applied voltage at 23 kV, flow rate at 11.67 μL/min and collector distance at 10 cm were selected to prepares the desirable electrospun nanofibres for applications and the further research.

scholarly journals Effects of Process Parameters on Structure and Properties of Melt-Blown Poly(Lactic Acid) Nonwovens for Skin Regeneration

2021 ◽  
Vol 12 (1) ◽  
pp. 16
Author(s):  
Ewa Dzierzkowska ◽  
Anna Scisłowska-Czarnecka ◽  
Marcin Kudzin ◽  
Maciej Boguń ◽  
Piotr Szatkowski ◽  
...  
Keyword(s):  
Air Temperature ◽  
Process Parameters ◽  
Cellular Response ◽  
3D Structure ◽  
Three Dimensional ◽  
Nonwoven Material ◽  
Processing Parameters ◽  
Skin Regeneration ◽  
Poly Lactic Acid ◽  
3D Scaffold

Skin regeneration requires a three-dimensional (3D) scaffold for cell adhesion, growth and proliferation. A type of the scaffold offering a 3D structure is a nonwoven material produced via a melt-blown technique. Process parameters of this technique can be adapted to improve the cellular response. Polylactic acid (PLA) was used to produce a nonwoven scaffold by a melt-blown technique. The key process parameters, i.e., the head and air temperature, were changed in the range from 180–270 °C to obtain eight different materials (MB1–MB8). The relationships between the process parameters, morphology, porosity, thermal properties and the cellular response were explored in this study. The mean fiber diameters ranged from 3 to 120 µm. The average material roughness values were between 47 and 160 µm, whereas the pore diameters ranged from 5 to 400 µm. The calorimetry thermograms revealed a correlation between the temperature parameters and crystallization. The response of keratinocytes and macrophages exhibited a higher cell viability on thicker fibers. The cell-scaffold interaction was observed via SEM after 7 days. This result proved that the features of melt-blown nonwoven scaffolds depended on the processing parameters, such as head temperature and air temperature. Thanks to examinations, the most suitable scaffolds for skin tissue regeneration were selected.

scholarly journals ELECTROSPRAY METHOD: PROCESSING PARAMETERS INFLUENCE ON MORPHOLOGY AND SIZE OF PCL PARTICLES

2018 ◽  
Vol 55 (1B) ◽  
pp. 209
Author(s):  
Linh Viet Nguyen Vu
Keyword(s):  
Flow Rate ◽  
Applied Voltage ◽  
Drug Carrier ◽  
Processing Parameters ◽  
Release Profile ◽  
Polymeric Microparticles ◽  
Size And Morphology ◽  
Imagej Software ◽  
H 20 ◽  
Scanning Electron

The polymeric microparticles using electrospray technique have been used effectively as the drug carrier, whereby controlled release of drug. The electrosprayed particles morphology and size dictated the degradation of polymer matrix, therefore they influenced the release profile from drug loaded microparticles. The effects of electrospray processing parameters (flow rate, applied voltage and distance from the tip of needle to collector) on morphology and size of polycaprolactone (PCL) particles were investigated by scanning electron microscopy (SEM) and ImageJ software. In this research, the PCL solution was prepared by dissolving PCL in Dichloromethane at 4.5 % solution. In addition, processing parameters such as the flow rate (0.5 mL/h, 1 mL/h, 1.5 mL/h, 2 mL/h and 4 mL/h), the applied voltage (15 kV, 18 kV and 24 kV) and the collecting distance (15 cm, 20 cm, and 25 cm) were changed to examine the effects of them on size and morphology of PCL particles. The results indicated that at the suitable electrospraying parameters (18 kV, 1.5 mL/h, 20–25 cm), microparticles have obtained the uniform and stable morphology while at higher flow rate (2 mL/h and 4 mL/h), the particles were deformed and had bigger size. 

scholarly journals High-resolution, reconfigurable printing of liquid metals with three-dimensional structures

2019 ◽  
Vol 5 (6) ◽  
pp. eaaw2844 ◽  
Author(s):  
Young-Geun Park ◽  
Hyeon Seok An ◽  
Ju-Young Kim ◽  
Jang-Ung Park
Keyword(s):  
High Resolution ◽  
Liquid Metals ◽  
3D Structure ◽  
Three Dimensional ◽  
Ambient Conditions ◽  
Oxide Interface ◽  
Free Standing ◽  
Direct Printing ◽  
Printed Patterns ◽  
Metal Layers

We report an unconventional approach for high-resolution, reconfigurable 3D printing using liquid metals for stretchable, 3D integrations. A minimum line width of 1.9 μm can be reliably formed using direct printing, and printed patterns can be reconfigured into diverse 3D structures with maintaining pristine resolutions. This reconfiguration can be performed multiple times, and it also generates a thin oxide interface that can be effective in preventing the spontaneous penetration of gallium atoms into different metal layers while preserving electrical properties under ambient conditions. Moreover, these free-standing features can be encapsulated with stretchable, conformal passivations. We demonstrate applications in the form of a reconfigurable antenna, which is tunable by changing geometeries, and reversibly movable interconnections used as mechanical switches. The free-standing 3D structure of electrodes is also advantageous for minimizing the number and space between interconnections, which is important for achieving higher integrations, as demonstrated in an array of microLEDs.

Production of Polymer Nanofibers Containing Hydroxyapatite by Electrospinning

2010 ◽  
Vol 659 ◽  
pp. 257-262 ◽  
Author(s):  
Mihály Tóth ◽  
Gréta Gergely ◽  
István Endre Lukács ◽  
Ferenc Wéber ◽  
Attila Lajos Tóth ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Flow Rate ◽  
Applied Voltage ◽  
Processing Parameters ◽  
Inorganic Component ◽  
Polymer Nanofibers ◽  
Bioactive Materials ◽  
Nanofiber Mats

Hydroxyapatite (HAP) is the main inorganic component of mammal bone and teeth. It is one of the few bioactive materials, which helps cell growing. The objective of this study was to fabricate hydroxyapatite-biopolimer nanofiber mats. To achieve this goal, two different suspensions were used. Approximately 1 μm diameter size fibers with large HAP agglomerates were fabricated using acetone and acetic acid. Fibers with a larger diameter size and homogenous distributed HAP particles were produced applying acetone and isopropanol. During the experiment the effect of the processing parameters: applied voltage, diameter of needle, the distance of the needle tip and the collector, flow rate was analyzed.

Methods for three-dimensional reconstruction of cellular components within a thick section

1986 ◽  
Vol 44 ◽  
pp. 18-21
Author(s):  
J. Frank ◽  
B. F. McEwen ◽  
M. Radermacher ◽  
C. L. Rieder
Keyword(s):  
Tilt Angle ◽  
Tomographic Reconstruction ◽  
3D Structure ◽  
Three Dimensional ◽  
Thick Section ◽  
Three Dimensional Reconstruction ◽  
Axis Ratio ◽  
Dimensional Reconstruction ◽  
Cellular Components

The tomographic reconstruction from multiple projections of cellular components, within a thick section, offers a way of visualizing and quantifying their three-dimensional (3D) structure. However, asymmetric objects require as many views from the widest tilt range as possible; otherwise the reconstruction may be uninterpretable. Even if not for geometric obstructions, the increasing pathway of electrons, as the tilt angle is increased, poses the ultimate upper limitation to the projection range. With the maximum tilt angle being fixed, the only way to improve the faithfulness of the reconstruction is by changing the mode of the tilting from single-axis to conical; a point within the object projected with a tilt angle of 60° and a full 360° azimuthal range is then reconstructed as a slightly elliptic (axis ratio 1.2 : 1) sphere.

Cryomicroscopy of crotoxin complex crystals at 400 KV

1989 ◽  
Vol 47 ◽  
pp. 826-827
Author(s):  
Jaap Brink ◽  
Wah Chiu
Keyword(s):  
Signal To Noise Ratio ◽  
3D Structure ◽  
Three Dimensional ◽  
Carbon Films ◽  
Depth Of Field ◽  
Basic Subunit ◽  
Ewald Sphere ◽  
Diffraction Patterns ◽  
Complex Crystals ◽  
Acidic Subunit

The crotoxin complex is a potent neurotoxin composed of a basic subunit (Mr = 12,000) and an acidic subunit (M = 10,000). The basic subunit possesses phospholipase activity whereas the acidic subunit shows no enzymatic activity at all. The complex's toxocity is expressed both pre- and post-synaptically. The crotoxin complex forms thin crystals suitable for electron crystallography. The crystals diffract up to 0.16 nm in the microscope, whereas images show reflections out to 0.39 nm2. Ultimate goal in this study is to obtain a three-dimensional (3D-) structure map of the protein around 0.3 nm resolution. Use of 100 keV electrons in this is limited; the unit cell's height c of 25.6 nm causes problems associated with multiple scattering, radiation damage, limited depth of field and a more pronounced Ewald sphere curvature. In general, they lead to projections of the unit cell, which at the desired resolution, cannot be interpreted following the weak-phase approximation. Circumventing this problem is possible through the use of 400 keV electrons. Although the overall contrast is lowered due to a smaller scattering cross-section, the signal-to-noise ratio of especially higher order reflections will improve due to a smaller contribution of inelastic scattering. We report here our preliminary results demonstrating the feasability of the data collection procedure at 400 kV.Crystals of crotoxin complex were prepared on carbon-covered holey-carbon films, quench frozen in liquid ethane, inserted into a Gatan 626 holder, transferred into a JEOL 4000EX electron microscope equipped with a pair of anticontaminators operating at −184°C and examined under low-dose conditions. Selected area electron diffraction patterns (EDP's) and images of the crystals were recorded at 400 kV and −167°C with dose levels of 5 and 9.5 electrons/Å, respectively.

Detection, Averaging, and 3D Reconstruction of Biological Specimens on Hypercubes (Transputer-based) Computers

1990 ◽  
Vol 48 (1) ◽  
pp. 454-455
Author(s):  
Jose-Maria Carazo ◽  
I. Benavides ◽  
S. Marco ◽  
J.L. Carrascosa ◽  
E.L. Zapata
Keyword(s):  
3D Reconstruction ◽  
3D Structure ◽  
Three Dimensional ◽  
Software Tools ◽  
Mapping Method ◽  
Computer Architectures ◽  
Parallel Computer ◽  
Reconstruction Process ◽  
Computing Power ◽  
Order Of Magnitude

Obtaining the three-dimensional (3D) structure of negatively stained biological specimens at a resolution of, typically, 2 - 4 nm is becoming a relatively common practice in an increasing number of laboratories. A combination of new conceptual approaches, new software tools, and faster computers have made this situation possible. However, all these 3D reconstruction processes are quite computer intensive, and the middle term future is full of suggestions entailing an even greater need of computing power. Up to now all published 3D reconstructions in this field have been performed on conventional (sequential) computers, but it is a fact that new parallel computer architectures represent the potential of order-of-magnitude increases in computing power and should, therefore, be considered for their possible application in the most computing intensive tasks.We have studied both shared-memory-based computer architectures, like the BBN Butterfly, and local-memory-based architectures, mainly hypercubes implemented on transputers, where we have used the algorithmic mapping method proposed by Zapata el at. In this work we have developed the basic software tools needed to obtain a 3D reconstruction from non-crystalline specimens (“single particles”) using the so-called Random Conical Tilt Series Method. We start from a pair of images presenting the same field, first tilted (by ≃55°) and then untilted. It is then assumed that we can supply the system with the image of the particle we are looking for (ideally, a 2D average from a previous study) and with a matrix describing the geometrical relationships between the tilted and untilted fields (this step is now accomplished by interactively marking a few pairs of corresponding features in the two fields). From here on the 3D reconstruction process may be run automatically.

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