Time matters for macroscopic membranes formed by alginate and cationic β-sheet peptides

Soft Matter ◽  
2020 ◽  
Vol 16 (44) ◽  
pp. 10132-10142
Author(s):  
Gal Yosefi ◽  
Topaz Levi ◽  
Hanna Rapaport ◽  
Ronit Bitton
Keyword(s):  
Nano Structure ◽  
Alginate Solution ◽  
Membrane Geometry ◽  
Β Sheet

The peptide age and membrane geometry affect the micro- and nano-structure of hierarchically ordered planar and spherical membranes constructed at the interface of cationic β-sheet peptides and alginate solution.

scholarly journals Nanostructure of bioactive glass affects bone cell attachment via protein restructuring upon adsorption

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ukrit Thamma ◽  
Tia J. Kowal ◽  
Matthias M. Falk ◽  
Himanshu Jain
Keyword(s):  
Bioactive Glass ◽  
Cell Response ◽  
Interfacial Layer ◽  
Cell Attachment ◽  
Bone Cell ◽  
Nano Structure ◽  
Rgd Sequence ◽  
Engineered Tissue ◽  
Α Helix ◽  
Β Sheet

AbstractThe nanostructure of engineered bioscaffolds has a profound impact on cell response, yet its understanding remains incomplete as cells interact with a highly complex interfacial layer rather than the material itself. For bioactive glass scaffolds, this layer comprises of silica gel, hydroxyapatite (HA)/carbonated hydroxyapatite (CHA), and absorbed proteins—all in varying micro/nano structure, composition, and concentration. Here, we examined the response of MC3T3-E1 pre-osteoblast cells to 30 mol% CaO–70 mol% SiO2 porous bioactive glass monoliths that differed only in nanopore size (6–44 nm) yet resulted in the formation of HA/CHA layers with significantly different microstructures. We report that cell response, as quantified by cell attachment and morphology, does not correlate with nanopore size, nor HA/CHO layer micro/nano morphology, or absorbed protein amount (bovine serum albumin, BSA), but with BSA’s secondary conformation as indicated by its β-sheet/α-helix ratio. Our results suggest that the β-sheet structure in BSA interacts electrostatically with the HA/CHA interfacial layer and activates the RGD sequence of absorbed adhesion proteins, such as fibronectin and vitronectin, thus significantly enhancing the attachment of cells. These findings provide new insight into the interaction of cells with the scaffolds’ interfacial layer, which is vital for the continued development of engineered tissue scaffolds.

Construction of an arranged nano-fibrous structure by selforganization of a designed amphiphilic peptide based on β- strand

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Makoto Hattori ◽  
Shujiro Hayashi ◽  
Hidenori Yokoi ◽  
Masayoshi Tanaka ◽  
Takatoshi Kinoshita
Keyword(s):  
Amino Acid Residues ◽  
Nano Structure ◽  
Lb Films ◽  
Langmuir Blodgett ◽  
Ph Values ◽  
Self Organized ◽  
Air Water Interface ◽  
Nano Fiber ◽  
Amphiphilic Peptide ◽  
Β Sheet

AbstractAn amphiphilic peptide having alternate sequence of hydrophobic and charged amino acid residues, RFDF16 (CH3CO-RFDFRFDFRFDFRFDF-NH2), was designed to form a β-sheet monolayer at the air/water interface. The peptide monolayer was prepared by Langmuir-Blodgett (LB) method. The LB films were transferred onto mica substrates without the compressing process at various pH values in order to investigate a self-organized structure of peptide monolayer. Surface morphology of LB films showed arranged nano-fibers which have differences in interval between fibers and their orientation depending on pH of the subphase. On the other hand, the self-organized nano-fiber was also re-arranged by compressing process. The nano-fibers became elongated and aligned upon compression to higher surface pressures. The exploitation of an electrostatic interaction and compressing process will allow a larger two-dimensionally regulated nano-structure.

Freeze fracture imaging and computer simulation of liposome structure: Membrane geometry and defects

1983 ◽  
Vol 41 ◽  
pp. 646-647
Author(s):  
Joseph A. Zasadzinski
Keyword(s):  
Liquid Crystalline ◽  
Freeze Fracture ◽  
Continuum Theory ◽  
Closed Surfaces ◽  
Straight Line ◽  
Low Weight ◽  
Concentric Spheres ◽  
Membrane Geometry ◽  
Dupin Cyclides ◽  
Limiting Case

At low weight fractions, many surfactant and biological amphiphiles form dispersions of lamellar liquid crystalline liposomes in water. Amphiphile molecules tend to align themselves in parallel bilayers which are free to bend. Bilayers must form closed surfaces to separate hydrophobic and hydrophilic domains completely. Continuum theory of liquid crystals requires that the constant spacing of bilayer surfaces be maintained except at singularities of no more than line extent. Maxwell demonstrated that only two types of closed surfaces can satisfy this constraint: concentric spheres and Dupin cyclides. Dupin cyclides (Figure 1) are parallel closed surfaces which have a conjugate ellipse (r1) and hyperbola (r2) as singularities in the bilayer spacing. Any straight line drawn from a point on the ellipse to a point on the hyperbola is normal to every surface it intersects (broken lines in Figure 1). A simple example, and limiting case, is a family of concentric tori (Figure 1b).To distinguish between the allowable arrangements, freeze fracture TEM micrographs of representative biological (L-α phosphotidylcholine: L-α PC) and surfactant (sodium heptylnonyl benzenesulfonate: SHBS)liposomes are compared to mathematically derived sections of Dupin cyclides and concentric spheres.

Green synthesis of mixed metallic nanoparticles using room temperature self-assembly

2017 ◽  
Vol 13 (2) ◽  
pp. 4671-4677 ◽  
Author(s):  
A. M. Abdelghany ◽  
A.H. Oraby ◽  
Awatif A Hindi ◽  
Doaa M El-Nagar ◽  
Fathia S Alhakami
Keyword(s):  
Self Assembly ◽  
Metallic Nanoparticles ◽  
Room Temperature ◽  
Bimetallic Nanoparticles ◽  
Reduction Process ◽  
Nano Particles ◽  
Nano Structure ◽  
Small Shift ◽  
Molar Ratios ◽  
Vis Spectroscopy

Bimetallic nanoparticles of silver (Ag) and gold (Au) were synthesized at room temperature using Curcumin. Reduction process of silver and gold ions with different molar ratios leads to production of different nanostructures including alloys and core-shells. Produced nanoparticles were characterized simultaneously with FTIR, UV/vis. spectroscopy, transmission electron microscopy (TEM), and Energy-dispersive X-ray (EDAX). UV/vis. optical absorption spectra of as synthesized nanoparticles reveals presence of surface palsmon resonance (SPR) of both silver at (425 nm) and gold at (540 nm) with small shift and broadness of gold band after mixing with resucing and capping agent in natural extract which suggest presence of bimetallic nano structure (Au/Ag). FTIR and EDAX data approve the presence of bimetallic nano structure combined with curcumin extract. TEM micrographs shows that silver and gold can be synthesized separately in the form of nano particles using curcumin extract. Synthesis of gold nano particles in presence of silver effectively enhance and control formation of bi-metallic structure.

Thermoluminescence properties of micro and nano structure hydroxyapatite after gamma irradiation

Kerntechnik ◽  
2016 ◽  
Vol 81 (6) ◽  
pp. 651-654 ◽  
Author(s):  
M. Shafaei ◽  
F. Ziaie ◽  
N. Hajiloo
Keyword(s):  
Gamma Irradiation ◽  
Nano Structure

FIB Micromachining and Nano-Structure Fabrication

1999 ◽  
Author(s):  
Raymond A. Lee ◽  
Patrick J. Wolpert
Keyword(s):  
High Precision ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Biological Applications ◽  
Optical Lens ◽  
Nano Structure ◽  
Beam System ◽  
Afm Tips ◽  
Established Technique ◽  
Made In

Abstract FIB Micromachining has long been an established technique, but until recently it has been overshadowed by the more mainstream semiconductor application of the Focused Ion Beam system. Nano- Structure fabrication using the FIB system has become more popular recently due to several factors. The need for sub-micron structures have grown significantly due to a need for enhanced optical and biological applications. Another reason for the growth in micromachining is the improvement made in the ability of FIB systems to produce geometric shapes with high precision. With the latest high-end FIB systems, it is possible to produce microstructures with tens of nano-meters of precision. Optical lens, AFM tips, and nano-apertures are all part of the growing application for FIB Micromachining. This paper will discuss the ability and limitations of the FIB system and some possible application for FIB Micromachining.

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