scholarly journals Characteristics of liposomes derived from egg yolk

2019 ◽  
Vol 17 (1) ◽  
pp. 763-778 ◽  
Author(s):  
Anna Kondratowicz ◽  
Marek Weiss ◽  
Wojciech Juzwa ◽  
Łukasz Majchrzycki ◽  
Grażyna Lewandowicz
Keyword(s):  
Food Industry ◽  
Size Structure ◽  
Structural Diversity ◽  
Egg Yolk ◽  
Structure Stability ◽  
Strong Correlations ◽  
Force Microscopy ◽  
Atomic Force ◽  
Cost Efficient ◽  
Shell Forming

AbstractLiposomes are nanocapsules successfully applied in pharmacy and medicine. Their usage in the food industry could be increased by the development of alternative, cost-efficient lecithin materials. This work is a continuation of the previous two papers describing five different extractions of egg yolk lecithins and the preassessment of their usefulness for liposome formation. Physicochemical properties of extracts differed due to distinct composition. The aim of this research was to further characterise the extracts-based liposomes, especially in terms of nanomechanical properties and structural diversity. Five previously described extracts were used for liposomes preparation employing Bangham technique. Vesicles were analysed with the use of dynamic light scattering, flow cytometry, and atomic force microscopy. The results were tested for correlation with the composition of the extracts. It was proved that the chemical composition of the shell-forming material determined the size, structure, stability, and mechanical properties of the vesicles. The observed effects were found to result not only from differences in the content of major components, i.e. phospholipids, acylglycerols, and cholesterol, but also in the relative proportions. Minor constituents, i.e. tocopherols and carotenoids, were also found to be of significance. Strong correlations between size and Zeta potential of the vesicles with the content of carotenoids were determined.

scholarly journals Effects of Size and Dispersity of Microcrystalline Celluloses on Size, Structure and Stability of Nanocrystalline Celluloses Extracted by Acid Hydrolysis

Nano LIFE ◽  
2014 ◽  
Vol 04 (04) ◽  
pp. 1441014 ◽  
Author(s):  
Qi Liu ◽  
Weiping Hao ◽  
Yongguang Yang ◽  
Aurore Richel ◽  
Canbin Ouyang ◽  
...  
Keyword(s):  
Particle Size ◽  
Acid Hydrolysis ◽  
Size Structure ◽  
Particle Sizes ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Sonication Treatment

Nanocrystalline celluloses (NCCs) were separated from four commercial microcrystalline celluloses (MCCs) by an acid hydrolysis–sonication treatment. Transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectrum, X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were conducted to investigate the NCCs. MCCs with different morphologies and particle sizes showed different aggregation degrees. The aggregation of MCCs followed the order MCC1 > MCC3 > MCC2 > MCC4, which is the same order of the heights of the resulting NCCs. The best uniformity and thermal stability were characterized for NCC3, which was produced by MCC3 with smallest original particle size and good dispersity among the four MCCs. This result suggests that both the original particle size and dispersity of MCCs had significant effects on separated NCCs.

scholarly journals Adhesion and Mechanical Properties of PDMS-Based Materials Probed with AFM: A Review

2018 ◽  
Vol 56 (1) ◽  
pp. 62-78 ◽  
Author(s):  
S. Vlassov ◽  
S. Oras ◽  
M. Antsov ◽  
I. Sosnin ◽  
B. Polyakov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Flexible Electronics ◽  
Food Industry ◽  
2D Materials ◽  
Organic Polymer ◽  
Adhesive Properties ◽  
Force Microscopy ◽  
Atomic Force ◽  
Dry Adhesives ◽  
Silicon Based

Abstract Polydimethylsiloxane (PDMS) is the most widely used silicon-based organic polymer, and is particularly known for its unusual rheological properties. PDMS has found extensive usage in various fields ranging from microfluidics and flexible electronics to cosmetics and food industry. In certain applications, like e.g. dry adhesives or dry transfer of 2D materials, adhesive properties of PDMS play crucial role. In this review we focus on probing the mechanical and adhesive properties of PDMS by means of atomic force microscopy (AFM). Main advantages and limitations of AFM-based measurements in comparison to macroscopic tests are discussed.

scholarly journals Structural diversity of erythrocytes in patients with hereditary spherocytosis

2018 ◽  
pp. 109-114
Author(s):  
M. N. Starodubtseva ◽  
E. F. Mitsura ◽  
I. A. Chelnokova ◽  
A. N. Kondrachuk ◽  
N. I. Yegorenkov
Keyword(s):  
Mechanical Property ◽  
Surface Layer ◽  
Hereditary Spherocytosis ◽  
Structural Diversity ◽  
Force Microscopy ◽  
Atomic Force ◽  
Study Results ◽  
Child Patients ◽  
Cell Shapes ◽  
Spectrin Network

Objective: to study the shape of erythrocytes and structure of their surface layer including the membrane and cytoskeleton (actin-spectrin network) in child patients with hereditary spherocytosis. Material and methods. The methods of optic and atomic-force microscopy were used in the study. Results. A variety of erythrocyte shapes with such prevalent types as discocytes, spherocytes, and echinocytes were revealed in the blood of the patients. The surface of certain cells contained microvesicules. The spatial heterogeneity of the structure of mechanical property maps of the cell surface layer was detected. Conclusion. The diversity of erythrocyte features in patients with hereditary spherocytosis is present both at the level of the cell shapes and at the level of the structure of mechanical property maps of their surface layer.

scholarly journals Atomic force microscopy reveals structural variability amongst nuclear pore complexes

2018 ◽  
Vol 1 (4) ◽  
pp. e201800142 ◽  
Author(s):  
George J Stanley ◽  
Ariberto Fassati ◽  
Bart W Hoogenboom
Keyword(s):  
Atomic Force Microscopy ◽  
Intrinsically Disordered Proteins ◽  
Structural Diversity ◽  
Disordered Proteins ◽  
Energetic Cost ◽  
Nuclear Pore ◽  
Central Channel ◽  
Force Microscopy ◽  
Intrinsically Disordered ◽  
Atomic Force

The nuclear pore complex (NPC) is a proteinaceous assembly that regulates macromolecular transport into and out of the nucleus. Although the structure of its scaffold is being revealed in increasing detail, its transport functionality depends upon an assembly of intrinsically disordered proteins (called FG-Nups) anchored inside the pore's central channel, which have hitherto eluded structural characterization. Here, using high-resolution atomic force microscopy, we provide a structural and nanomechanical analysis of individual NPCs. Our data highlight the structural diversity and complexity at the nuclear envelope, showing the interplay between the lamina network, actin filaments, and the NPCs. It reveals the dynamic behaviour of NPC scaffolds and displays pores of varying sizes. Of functional importance, the NPC central channel shows large structural diversity, supporting the notion that FG-Nup cohesiveness is in a range that facilitates collective rearrangements at little energetic cost. Finally, different nuclear transport receptors are shown to interact in qualitatively different ways with the FG-Nups, with particularly strong binding of importin-β.

In situ Determination and Imaging of Physical Properties of Soft Organic Materials by Analytical Transmission Electron Microscopy

2014 ◽  
Vol 20 (3) ◽  
pp. 916-923 ◽  
Author(s):  
Nadejda B. Matsko ◽  
Franz P. Schmidt ◽  
Ilse Letofsky-Papst ◽  
Artem Rudenko ◽  
Vikas Mittal
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Soft Materials ◽  
Analytical Transmission Electron Microscopy ◽  
Strong Correlations ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
Phase Images ◽  
Material Contrast

AbstractAnalytical transmission electron microscopy (ATEM) offers great flexibility in identification of the structural—chemical organization of soft materials at the level of individual macromolecules. However, the determination of mechanical characteristics such as hardness/elasticity of the amorphous and polycrystalline organic substances by ATEM has been problematic so far. Here, we show that energy filtered TEM (EFTEM) measurements enable direct identification and study of mechanical properties in complex (bio-)polymer systems of relevance for different industrial and (bio-)medical applications. We experimentally demonstrate strong correlations between hardness/elasticity of different polymers (polycaprolactone, polylactid, polyethelene, etc.) and their volume plasmon energy. Thickness and anisotropy effects, which substantially mask the material contrast in EFTEM bulk plasmon images, can be adequately removed by normalizing the latter by carbon elemental map. EFTEM data has been validated using atomic force microscopy phase images, where phase shift related to the hardness and elastic modulus of the materials.

Effect of Exposure Time on Plasma Modified Polyvinylidenefluoride-Trifluoroethylene (PVDF-TrFE) Film Surfaces

2014 ◽  
Vol 895 ◽  
pp. 138-141 ◽  
Author(s):  
Muhamad Naiman Sarip ◽  
Rozana Mohd Dahan ◽  
Yap Seong Ling ◽  
Mohamad Hafiz Mohd Wahid ◽  
Adillah Nurashikin Arshad ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Contact Angle ◽  
Exposure Time ◽  
Food Industry ◽  
Argon Plasma ◽  
Water Contact ◽  
Force Microscopy ◽  
Atomic Force ◽  
Good Biocompatibility ◽  
Surface Modified

This study investigates the plasma surface modified spin coated PVDF-TrFE (70/30) film of 200nm thick using Atomic Force Microscopy (AFM), Water Contact Angle (WCA) and Fourier Transform Infrared Spectroscopy (FTIR). The surface of the spin coated PVDF-TrFE film were modified using 13.56 MHz rf Argon plasma. The exposure time of the charged particle on PVDF-TrFE films were varied for 1, 3, 5, 7 and 9mins. Prior to modification, the average surface roughness observed was 3.5nm. However upon modification, the surface roughness was increased to 9.5nm. The contact angle of the surface modified film was reduced from 89° to 58°. The increase in surface roughness and wettability of the modified film provided good biocompatibility. This finding created great interest in developing functional polymer suitable for applications in areas such are biomedical, bio-analytical assays, textile and even food industry.

Cryogenic atomic force microscopy

1991 ◽  
Vol 49 ◽  
pp. 54-55
Author(s):  
K. A. Fisher ◽  
M. G. L. Gustafsson ◽  
M. B. Shattuck ◽  
J. Clarke
Keyword(s):  
Room Temperature ◽  
Rapid Freezing ◽  
Cryogenic Temperatures ◽  
Soft Or ◽  
Electrically Conductive ◽  
Force Microscopy ◽  
Flexible Molecules ◽  
Advantages And Disadvantages ◽  
Atomic Force ◽  
Chemical Perturbation

The atomic force microscope (AFM) is capable of imaging electrically conductive and non-conductive surfaces at atomic resolution. When used to image biological samples, however, lateral resolution is often limited to nanometer levels, due primarily to AFM tip/sample interactions. Several approaches to immobilize and stabilize soft or flexible molecules for AFM have been examined, notably, tethering coating, and freezing. Although each approach has its advantages and disadvantages, rapid freezing techniques have the special advantage of avoiding chemical perturbation, and minimizing physical disruption of the sample. Scanning with an AFM at cryogenic temperatures has the potential to image frozen biomolecules at high resolution. We have constructed a force microscope capable of operating immersed in liquid n-pentane and have tested its performance at room temperature with carbon and metal-coated samples, and at 143° K with uncoated ferritin and purple membrane (PM).

AFM study of the dynamics of α-alumina surface faceting during high-temperature processing

1995 ◽  
Vol 53 ◽  
pp. 334-335 ◽  
Author(s):  
Michael W. Bench ◽  
Jason R. Heffelfinger ◽  
C. Barry Carter
Keyword(s):  
High Temperature ◽  
Thin Foil ◽  
Sem Analysis ◽  
Conductive Coatings ◽  
Force Microscopy ◽  
Minimal Sample ◽  
Atomic Force ◽  
Formation And Evolution ◽  
High Temperature Processing ◽  
Nominal Surface

To gain a better understanding of the surface faceting that occurs in α-alumina during high temperature processing, atomic force microscopy (AFM) studies have been performed to follow the formation and evolution of the facets. AFM was chosen because it allows for analysis of topographical details down to the atomic level with minimal sample preparation. This is in contrast to SEM analysis, which typically requires the application of conductive coatings that can alter the surface between subsequent heat treatments. Similar experiments have been performed in the TEM; however, due to thin foil and hole edge effects the results may not be representative of the behavior of bulk surfaces.The AFM studies were performed on a Digital Instruments Nanoscope III using microfabricated Si3N4 cantilevers. All images were recorded in air with a nominal applied force of 10-15 nN. The alumina samples were prepared from pre-polished single crystals with (0001), , and nominal surface orientations.

Scanning tunneling microscopy and atomic force microscopy: New tools for biology

1989 ◽  
Vol 47 ◽  
pp. 778-779
Author(s):  
CE Bracker ◽  
P. K. Hansma
Keyword(s):  
Physical Property ◽  
Scanning Probe ◽  
Scanning Tunneling ◽  
Small Scale ◽  
Tunneling Microscopy ◽  
Force Microscopy ◽  
New Family ◽  
Small Probe ◽  
Atomic Force ◽  
Transmission Electron

A new family of scanning probe microscopes has emerged that is opening new horizons for investigating the fine structure of matter. The earliest and best known of these instruments is the scanning tunneling microscope (STM). First published in 1982, the STM earned the 1986 Nobel Prize in Physics for two of its inventors, G. Binnig and H. Rohrer. They shared the prize with E. Ruska for his work that had led to the development of the transmission electron microscope half a century earlier. It seems appropriate that the award embodied this particular blend of the old and the new because it demonstrated to the world a long overdue respect for the enormous contributions electron microscopy has made to the understanding of matter, and at the same time it signalled the dawn of a new age in microscopy. What we are seeing is a revolution in microscopy and a redefinition of the concept of a microscope.Several kinds of scanning probe microscopes now exist, and the number is increasing. What they share in common is a small probe that is scanned over the surface of a specimen and measures a physical property on a very small scale, at or near the surface. Scanning probes can measure temperature, magnetic fields, tunneling currents, voltage, force, and ion currents, among others.

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