scholarly journals Characterization of Lipid Membrane Properties for Tunable Electroporation

2012 ◽  
Author(s):  
H. Jeremy Cho ◽  
Shalabh C. Maroo ◽  
Evelyn N. Wang
Keyword(s):  
Lipid Bilayers ◽  
Lipid Membrane ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Membrane Properties ◽  
Force Microscopy ◽  
Packing Structure ◽  
Atomic Force ◽  
Dynamics Simulations

Lipid bilayers form nanopores on the application of an electric field. This process of electroporation can be utilized in different applications ranging from targeted drug delivery in cells to nano-gating membrane for engineering applications. However, the ease of electroporation is dependent on the surface energy of the lipid layers and thus directly related to the packing structure of the lipid molecules. 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) lipid monolayers were deposited on a mica substrate using the Langmuir-Blodgett (LB) technique at different packing densities and analyzed using atomic force microscopy (AFM). The wetting behavior of these monolayers was investigated by contact angle measurement and molecular dynamics simulations. It was found that an equilibrium packing density of liquid-condensed (LC) phase DPPC likely exists and that water molecules can penetrate the monolayer displacing the lipid molecules. The surface tension of the monolayer in air and water was obtained along with its breakthrough force.

Preparation and Characterization of Poly Amide Amine (Generation 4.0) Self-Assembled Monolayer on Si (100)

2008 ◽  
Vol 373-374 ◽  
pp. 645-648 ◽  
Author(s):  
Bao Feng Cui ◽  
Jian Min Chen ◽  
Jun Yan Zhang ◽  
Hui Di Zhou
Keyword(s):  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Fourth Generation ◽  
Self Assembled Monolayer ◽  
Wear Resistant ◽  
Force Microscopy ◽  
Atomic Force ◽  
Wear Life ◽  
Self Assembled

The fourth generation of poly amide amine molecular self-assembled monolayer (PAMAM (G4.0)-SAM) was prepared on hydroxylated Si (111) substrate by a self-assembled technique from specially formulated solution. The PAMAM (G4.0)-SAM were characterized by means of contact angle measurement, ellipsometry, X-ray photoelectron spectroscope (XPS), and atomic force microscopy (AFM). The tribological properties of the as-prepared thin films sliding against a steel ball were evaluated on a friction and wear tester. The tribological results show that the friction coefficient of monocrystal line silicon substrate reduces from 0.6 to 0.18 due to the formation of PAMAM-SAMs on its surface. And the PAMAM (G4.0) -SAM has longer wear life (18000 sliding pass). It is demonstrated that PAMAM (G4.0) -SAM exhibited good wear resistant property. In conclusion, the PAMAM (G4.0)-SAM which possesses good wear resistant property was successfully prepared and the film.

scholarly journals Surface Properties of Alginate/Chitosan Biofilm for Wound Healing Application

2020 ◽  
Vol 1010 ◽  
pp. 602-607
Author(s):  
Maizlinda Izwana Idris ◽  
Mohammed Firdaus Adzhari ◽  
Siti Natrah Abdul Bakil ◽  
Tee Chuan Lee ◽  
Mohamad Ali Selimin ◽  
...  
Keyword(s):  
Contact Angle ◽  
Wound Healing ◽  
Surface Properties ◽  
Healing Process ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Force Microscopy ◽  
Good Surface ◽  
Atomic Force ◽  
Biopolymer Film

This work focuses on the fabrication of film based on natural biopolymers for wound healing application. Alginate and chitosan were choosen because of their oustanding properties such as biocompatible, hydrophilic and non-toxic. Earlier, the biopolymer film was fabricated by using alginate 1% wt and chitosan 1% wt. solutions at volume ratios of 99:1 and 97:3. Next, the biopolymer film solution was cross-linked with 1M CaCl2.2H2O for two hours and later dried for 24 hours at room temperature. Then, the surface properties of the prepared biopolymer films were characterised via Field Emission Scanning Electron Microscopy (FESEM), Atomic Force Microscopy (AFM) and contact angle measurement. It was observed that the surface of the biopolymer film became rougher as the volume of the chitosan increases. This condition was confirmed with average surface roughness, RA for biopolymer film with ratio of 97:3 resulted in higher values. Also it was found that the surface of biopolymer films were hydrophilic after the contact angle was less than 90°. This can be concluded that the biopolymer based on alginate/chitosan is a promising candidate for wound healing materials particularly with good surface properties for faster healing process at the wound areas.

Surface hydrophilizing modification of polytetrafluoroethylene/glass fiber fabric through oxidant-induced polydopamine deposition

2019 ◽  
Vol 50 (3) ◽  
pp. 364-379
Author(s):  
Yanfen Zhou ◽  
Liang Jiang ◽  
Zhiqing Jiang ◽  
Shaojuan Chen ◽  
Jianwei Ma
Keyword(s):  
Contact Angle ◽  
Glass Fiber ◽  
Water Contact Angle ◽  
Mechanical Stability ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Water Contact ◽  
Force Microscopy ◽  
Atomic Force ◽  
Fiber Fabric

This paper reports surface hydrophilizing modification of polytetrafluoroethylene/glass fiber fabric by employing bio-inspired polydopamine functionalization. The modification process was accelerated by introducing sodium periodate (NaIO4) as oxidant. Surface morphology and chemical composition of the modified polytetrafluoroethylene/glass fiber fabric were characterized by using scanning electron microscopy, atomic force microscopy (AFM), and Fourier transform infrared spectroscopy, respectively. Hydrophilicity of the polytetrafluoroethylene/glass fiber fabric was investigated through water contact angle measurement. It was found that polydopamine successfully deposited on the surface of polytetrafluoroethylene/glass fiber fabric and the uniformity of the polydopamine coating increased with increasing modification time. Water contact angle of polytetrafluoroethylene/glass fiber fabric decreased after polydopamine modification and reached 29° when the sample was treated for 120 min, indicating an improved hydrophilic performance. The formed polydopamine coating was also demonstrated to have reliable chemical and mechanical stability.

Structure of Silane Films and their Adhesion Properties

1995 ◽  
Vol 407 ◽  
Author(s):  
Y. Carolina Araujo ◽  
Pedro G. Toledo
Keyword(s):  
Contact Angle ◽  
Surface Coverage ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Flow In Porous Media ◽  
Adhesion Properties ◽  
Force Microscopy ◽  
Angle Measurements ◽  
Atomic Force ◽  
Glass Surfaces

ABSTRACTSilane films, their structure and stability, are of great interest in processes such as flow in porous media, mineral flotation, chromatography and corrosion. Here, the structure of octadecyl thriclorosilane (OTS) films on glass surfaces is studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM), their adhesion properties by contact angle measurements and adhesion tests. Complete glass surface coverage by the silane is attained after an immersion time tc characteristic of the OTS compound. The time evolution of the OTS films regarding surface coverage is monitored by SEM with a BSE detector, by measuring the OTS film thicknesses from XPS data, by AFM and by contact angle measurement. At tc the structure of the films changes from micromolecular to macromolecular. Below tc the glass coverage has a fractal geometry and various degrees of hydrophobicity are possible. At t > tc the surface coverage is complete and the contact angle achieved a well defined constant value.

Electrophoretic Deposition of Hydroxyapatite Nanocrystal

2006 ◽  
Vol 309-311 ◽  
pp. 643-646 ◽  
Author(s):  
Akira Monkawa ◽  
Toshiyuki Ikoma ◽  
Shunji Yunoki ◽  
Kazushi Ohta ◽  
M. Tanaka
Keyword(s):  
Thin Layer ◽  
Electrophoretic Deposition ◽  
Gold Surface ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Coating Layers

Homogeneous nano-thin layer of hydroxyapatite (HAp) nanocrystals on the gold surface was fabricated by an electrophoretic deposition method (EPD); the HAp nanocrystals were dispersed into ethanol and the applied voltage was varied. The HAp nanocrystals were prepared by a wet method at 4 °C and 80 °C, which were characterized by X-ray diffraction and Fourier-transform infrared spectroscopy. The micro-thin layer of HAp nanocrystals was initially formed, and the ultrasonic treatments can remove the surplus nanocrystals from the surface. The nanostructure of the surface was investigated by atomic force microscopy and contact angle measurement. The thickness of coating layers was approximately 20nm and the root mean square (RMS) roughness was under 6.6 nm, which was clearly depended on the crystal sizes, applied voltages and applied times.

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