scholarly journals Preparation of Poly(L,L-Lactide) Microparticles via Pickering Emulsions Using Chitin Nanocrystals

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
T. S. Demina ◽  
Yu. S. Sotnikova ◽  
A. V. Istomin ◽  
Ch. Grandfils ◽  
T. A. Akopova ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Total Yield ◽  
Crab Shell ◽  
Pickering Emulsions ◽  
Water Emulsion ◽  
Force Microscopy ◽  
Aspect Ratios ◽  
Atomic Force ◽  
Evaporation Technique ◽  
Oil Water

The aim of the present study was to investigate an ability of chitin nanocrystals to be used as stabilizing components for fabrication of poly(L,L-lactide) microparticles via the Pickering oil/water emulsion solvent evaporation technique. The anisometric chitin nanocrystals were extracted from two different samples of crab shell chitin via acetic hydrolysis and analyzed using atomic force microscopy, dynamic light scattering, and FTIR spectroscopy. The extracted nanocrystals showed no difference in the chemical structure but possessed different morphology and aspect ratios as a function of raw chitin used. The effect of chitin nanocrystals characteristics and concentration in the aqueous phase on the total yield, size distribution, and shape and surface morphology of the prepared polylactide microparticles was evaluated.

scholarly journals Polysaccharides as Stabilizers for Polymeric Microcarriers Fabrication

Polymers ◽  
2021 ◽  
Vol 13 (18) ◽  
pp. 3045
Author(s):  
Tatiana S. Demina ◽  
Liubov A. Kilyashova ◽  
Tatiana N. Popyrina ◽  
Eugenia A. Svidchenko ◽  
Sankar Bhuniya ◽  
...  
Keyword(s):  
Chemical Structure ◽  
Total Yield ◽  
Solvent Evaporation ◽  
Prolonged Release ◽  
Water Emulsion ◽  
Polymeric Microparticles ◽  
One Step ◽  
Evaporation Technique ◽  
Oil Water ◽  
Emulsifying Ability

Biodegradable polymeric microparticles are widely used in drug delivery systems with prolonged-release profiles and/or cell microcarriers. Their fabrication via the oil/water emulsion solvent evaporation technique has normally required emulsifiers in the aqueous phase. The present work aims to evaluate the effectiveness of various polysaccharides, such as chitosan, hyaluronic acid, cellulose, arabinogalactan, guar and their derivatives, as an alternative to synthetic surfactants for polylactide microparticle stabilization during their fabrication. Targeted modification of the biopolymer’s chemical structure was also tested as a tool to enhance polysaccharides’ emulsifying ability. The transformation of biomacromolecules into a form of nanoparticle via bottom-up or top-down methods and their subsequent application for microparticle fabrication via the Pickering emulsion solvent evaporation technique was useful as a one-step approach towards the preparation of core/shell microparticles. The effect of polysaccharides’ chemical structure and the form of their application on the polylactide microparticles’ total yield, size distribution and morphology was evaluated. The application of polysaccharides has great potential in terms of the development of green chemistry and the biocompatibility of the formed microparticles, which is especially important in biomedicine application.

Cold Deposition of Zinc Sulfide Optical Waveguides Using Thermoelectric Device

2011 ◽  
Vol 264-265 ◽  
pp. 856-861 ◽  
Author(s):  
Saafie Salleh ◽  
Harvey N. Rutt ◽  
M.N. Dalimin ◽  
Muhamad Mat Salleh
Keyword(s):  
Zinc Sulfide ◽  
Optical Waveguides ◽  
Thermoelectric Device ◽  
Force Microscopy ◽  
Prism Coupler ◽  
Atomic Force ◽  
Propagation Losses ◽  
Evaporation Technique ◽  
Scanning Detection ◽  
Zns Films

Zinc sulfide (ZnS) thin films as the waveguide medium have been deposited onto oxidized silicon wafer substrates at cold temperature (Tcold = –50oC) and ambient temperature (Tambient = 25oC) by thermal evaporation technique. The surface morphology of ZnS films were pictured with an atomic force microscopy (AFM) and the surface roughness were calculated from the AFM images. The propagation losses of the samples were measured using a scanning detection technique attached to a prism coupler. The AFM results revealed that the surface of cold deposited ZnS film is rougher than the surface of ambient deposited ZnS film. The propagation losses of the cold deposited ZnS waveguide are consistently lower than the ambient deposited ZnS waveguide at all measured wavelengths.

scholarly journals Chemical structure imaging of a single molecule by atomic force microscopy at room temperature

2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Kota Iwata ◽  
Shiro Yamazaki ◽  
Pingo Mutombo ◽  
Prokop Hapala ◽  
Martin Ondráček ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Single Molecule ◽  
Chemical Structure ◽  
Room Temperature ◽  
Force Microscopy ◽  
Atomic Force

scholarly journals Nanoscale Molecular Characterisation of Hair Cuticles using Integrated AFM-IR

2020 ◽  
Author(s):  
A. P. Fellows ◽  
M. T. L. Casford ◽  
P. B. Davies
Keyword(s):  
Chemical Structure ◽  
High Surface ◽  
Great Majority ◽  
Diffraction Limit ◽  
Chemical Investigation ◽  
Molecular Characterisation ◽  
Force Microscopy ◽  
Atomic Force ◽  
Surface Spectroscopy ◽  
Significant Chemical

AbstractThe nanometre-scale topography and chemical structure of hair cuticles has been investigated by vibrational spectroscopy and imaging in two spectral regions. The combination of Atomic Force Microscopy with a tuneable infrared laser (AFM-IR) circumvents the diffraction limit that has impaired traditional infrared spectroscopy, facilitating surface spectroscopy at ultra-spatial resolution. The variation in protein and lipid content of the cuticle cell surface approaching its edge, as well as the exposed layered structure of the cell at the edge itself, was investigated. Furthermore, the contribution of cystine-related products to the cuticle layers was determined. The variation of protein, lipid and cystine composition in the observed layers, as well as the measured dimensions of each, correspond closely to that of the epicuticle, A-layer, exocuticle and endocuticle layers of the cuticle cell sub-structure.Statement of SignificanceUsing AFM-IR to analyse the nanoscale cuticle features is both significant and novel in the field. Thus far, the great majority of work on the chemical investigation of the structure of hair has been limited to bulk measurements, or subject to the diffraction limit associated with traditional IR spectroscopies and microscopies. AFM-IR circumvents this diffraction limit and allows nanometre-scale, localised chemical investigation with high surface selectivity. While non-chemical investigations, e.g. those using Transmission Election Microscopy, have previously shown cuticles to have a layered substructure, AFM-IR sheds light on significant chemical variations of protein and lipid compositions within such layers, enabling their quantification.

Facet Formation on Single Crystal TiO2 Surfaces Studied by Atomic Force Microscopy

1991 ◽  
Vol 237 ◽  
Author(s):  
M. D. Antonik ◽  
J. C. Edwards ◽  
R. J. Lad
Keyword(s):  
Atomic Force Microscopy ◽  
Single Crystal ◽  
Surface Defects ◽  
Complex Surface ◽  
Force Microscopy ◽  
Aspect Ratios ◽  
Atomic Force ◽  
Small Height ◽  
Low Energy Electron ◽  
Large Distribution

ABSTRACTAtomic force microscopy (AFM) and low energy electron diffraction (LEED) have been used to study the faceting behavior on (001) and (100) surfaces of a TiO2 single crystal. On the TiO2 (001) surface, LEED patterns characteristic of {011} facet planes develop after annealing below 900 °C in agreement with previous studies, but AFM shows a complex surface morphology consisting of a large distribution of facet sizes and orientations. After annealing at 1300 °C, facets do not form but rather a network of 5 – 30 nm high ridges develops over the entire surface. These ridges may be the result of surface defects produced by changes in bulk stoichiometry during annealing. On the TiO2 (100) surface, facets are also observed after annealing below 900 °C. However, these facets have extremely small height to width aspect ratios and are not discernible with LEED.

Structural, morphology and electrical properties of layered copper selenide thin film

Open Physics ◽  
2009 ◽  
Vol 7 (2) ◽  
Author(s):  
J. Ying Chyi Liew ◽  
Zainal Talib ◽  
W. Mahmood ◽  
M. Yunus ◽  
Zulkarnain Zainal ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Surface Roughness ◽  
Grain Size ◽  
Copper Selenide ◽  
Layer By Layer ◽  
Structural Morphology ◽  
Force Microscopy ◽  
Atomic Force ◽  
Average Grain Size ◽  
Evaporation Technique

AbstractThin films of copper selenide (CuSe) were physically deposited layer-by-layer up to 5 layers using thermal evaporation technique onto a glass substrate. Various film properties, including the thickness, structure, morphology, surface roughness, average grain size and electrical conductivity are studied and discussed. These properties are characterized by X-ray diffraction (XRD), atomic force microscopy (AFM), ellipsometer and 4 point probe at room temperature. The dependence of electrical conductivity, surface roughness, and average grain size on number of layers deposited is discussed.

The Chemical Structure of a Molecule Resolved by Atomic Force Microscopy

Science ◽  
2009 ◽  
Vol 325 (5944) ◽  
pp. 1110-1114 ◽  
Author(s):  
L. Gross ◽  
F. Mohn ◽  
N. Moll ◽  
P. Liljeroth ◽  
G. Meyer
Keyword(s):  
Atomic Force Microscopy ◽  
Chemical Structure ◽  
Force Microscopy ◽  
Atomic Force
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