scholarly journals Creation of Ionically Crosslinked Tri-Layered Chitosan Membranes to Simulate Different Human Skin Properties

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1807
Author(s):  
Rocío Guerle-Cavero ◽  
Blanca Lleal-Fontàs ◽  
Albert Balfagón-Costa
Keyword(s):  
Elastic Modulus ◽  
Human Skin ◽  
Sodium Tripolyphosphate ◽  
Snow Crab ◽  
Suitable Material ◽  
Cosmetic Industry ◽  
Novel Method ◽  
Current Article ◽  
Chitosan Membranes

In 2023, new legislation will ban the use of animals in the cosmetic industry worldwide. This fact, together with ethical considerations concerning the use of animals or humans in scientific research, highlights the need to propose new alternatives for replacing their use. The aim of this study is to create a tri-layered chitosan membrane ionically crosslinked with sodium tripolyphosphate (TPP) in order to simulate the number of layers in human skin. The current article highlights the creation of a membrane where pores were induced by a novel method. Swelling index, pore creation, and mechanical property measurements revealed that the swelling index of chitosan membranes decreased and, their pore formation and elasticity increased with an increase in the Deacetylation Grade (DDA). Additionally, the results demonstrate that chitosan’s origin can influence the elastic modulus value and reproducibility, with higher values being obtained with seashell than snow crab or shrimp shells. Furthermore, the data show that the addition of each layer, until reaching three layers, increases the elastic modulus. Moreover, if layers are crosslinked, the elastic modulus increases to a much greater extent. The characterization of three kinds of chitosan membranes was performed to find the most suitable material for studying different human skin properties.

Extracting the Elastic Modulus of Compliant Materials Using a Novel Plate Bulge Testing Technique

2008 ◽  
Author(s):  
S. Golan ◽  
D. Elata ◽  
U. Dinnar
Keyword(s):  
Elastic Modulus ◽  
Plate Theory ◽  
Biological Tissues ◽  
Bulge Test ◽  
The Novel ◽  
Membrane Mechanics ◽  
Testing Technique ◽  
Bulge Testing ◽  
Novel Method

The mechanical properties of compliant materials such as biological tissues and biocompatible soft polymers are essential in medical research and engineering applications. These properties are often determined using techniques that require costly instrumentation (e.g. pull test machines). Alternative and more accessible methods can significantly aid the characterization process. The bulge test determines a material elastic modulus by analyzing the pressure-deflection response of thin samples made of this material. The technique has been extensively employed in the characterization of metals and semiconductors (modulus ∼ 100 GPa). By employing plate rather than membrane mechanics, the present study extends bulge testing to characterize materials with a modulus that is five orders of magnitude lower (∼ 1 MPa). The novel method is demonstrated analytically using plate theory, numerically using finite element modeling and experimentally by successfully applying it to polydimethylsiloxane (modulus ∼ 1.33 MPa). The introduced technique does not require costly equipment, is simple to implement and presents an appealing alternative to current characterization approaches.

scholarly journals A Universal Model for the Log-Normal Distribution of Elasticity in Polymeric Gels and Its Relevance to Mechanical Signature of Biological Tissues

Biology ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 64
Author(s):  
Arnaud Millet
Keyword(s):  
Elastic Modulus ◽  
Normal Distribution ◽  
Biological Tissues ◽  
Force Microscopy ◽  
Polymeric Gels ◽  
Atomic Force ◽  
Clear Explanation ◽  
Log Normal ◽  
Log Normal Distribution

The mechanosensitivity of cells has recently been identified as a process that could greatly influence a cell’s fate. To understand the interaction between cells and their surrounding extracellular matrix, the characterization of the mechanical properties of natural polymeric gels is needed. Atomic force microscopy (AFM) is one of the leading tools used to characterize mechanically biological tissues. It appears that the elasticity (elastic modulus) values obtained by AFM presents a log-normal distribution. Despite its ubiquity, the log-normal distribution concerning the elastic modulus of biological tissues does not have a clear explanation. In this paper, we propose a physical mechanism based on the weak universality of critical exponents in the percolation process leading to gelation. Following this, we discuss the relevance of this model for mechanical signatures of biological tissues.

Molecular characterization of reconstructed skin model by Raman microspectroscopy: Comparison with excised human skin

Biopolymers ◽  
2007 ◽  
Vol 87 (4) ◽  
pp. 261-274 ◽  
Author(s):  
Ali Tfayli ◽  
Olivier Piot ◽  
Florence Draux ◽  
Franck Pitre ◽  
Michel Manfait
Keyword(s):  
Molecular Characterization ◽  
Human Skin ◽  
Raman Microspectroscopy ◽  
Skin Model ◽  
Reconstructed Skin

scholarly journals Molecular Characterization of Human Skin Response to Diphencyprone at Peak and Resolution Phases: Therapeutic Insights

2014 ◽  
Vol 134 (10) ◽  
pp. 2531-2540 ◽  
Author(s):  
Nicholas Gulati ◽  
Mayte Suárez-Fariñas ◽  
Judilyn Fuentes-Duculan ◽  
Patricia Gilleaudeau ◽  
Mary Sullivan-Whalen ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Human Skin ◽  
Skin Response

Polycrystalline Silicon Gettering Layers with Controlled Residual Stress

2013 ◽  
Vol 205-206 ◽  
pp. 284-289 ◽  
Author(s):  
David Lysáček ◽  
Petr Kostelník ◽  
Petr Pánek
Keyword(s):  
Residual Stress ◽  
Vapor Deposition ◽  
Polycrystalline Silicon ◽  
Opposite Sign ◽  
Chemical Vapor ◽  
Pressure Chemical ◽  
Novel Method ◽  
The Individual ◽  
Scanning Electron

We report on a novel method of low pressure chemical vapor deposition of polycrystalline silicon layers used for external gettering in silicon substrate for semiconductor applications. The proposed method allowed us to produce layers of polycrystalline silicon with pre-determined residual stress. The method is based on the deposition of a multilayer system formed by two layers. The first layer is intentionally designed to have tensile stress while the second layer has compressive stress. Opposite sign of the residual stresses of the individual layers enables to pre-determine the residual stress of the gettering stack. We used scanning electron microscopy for structural characterization of the layers and intentional contamination for demonstration of the gettering properties. Residual stress of the layers was calculated from the wafer curvature.

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