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Highly Oriented Nanofibers Produced by
Electrospinning
Neda Shah Hosseini, Nabyl Khenoussi, Laurence Schacher, Dominique
Adolphe, Bertrand Simon, Amir Hekmati, Yann Hietter, Jean Beyer
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Highly Oriented Nanofibers Produced by
Electrospinning
Poster · May 2016 CITATIONS0
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8 authors, including: Some of the authors of this publication are also working on these related projects: Highly Oriented Nanofibers Produced by ElectrospinningView project Electrospinning
View project Nabyl Khenoussi Université de Haute-Alsace 56 PUBLICATIONS 48 CITATIONS SEE PROFILE Laurence Schacher Université de Haute-Alsace 130 PUBLICATIONS 336 CITATIONS SEE PROFILE Bertrand Simon Université de Haute-Alsace 25 PUBLICATIONS 264 CITATIONS SEE PROFILE Amir Houshang Hekmati Islamic Azad University, South Tehran Branch 34 PUBLICATIONS 18 CITATIONS SEE PROFILE
All content following this page was uploaded by Neda Shah Hosseini on 13 June 2016.
Highly Oriented Nanofibers Produced by Electrospinning
Neda Shah Hosseini1, Nabyl Khenoussi1, Laurence Schacher1, Dominique Adolphe1, Bertrand Simon2, Amir Houshang
Hekmati3, Yann Hietter1, Jean Beyer1
1Laboratoire de Physique et Mécanique Textiles EA 4365 – UHA Mulhouse, France
2 Laboratoire de Modélisation Intelligence Processus Systèmes (MIPS) EA 2332 – UHA Mulhouse, France 3Department of textile engineering, Faculty of Engineering, South Tehran branch, Islamic Azad University, Tehran, Iran
neda.shahoseini@gmail.com
STATEMENT OF PURPOSE
This project consists of production of Polyamide-6 (PA-6) nanofiber with patterned structure by using novel collectors in electrospinning. These collectors (under patent process) will allow producing both oriented and non-oriented nanofibers in one scaffold for biomedical applications. These static collectors make it possible to have different nanofibers' structure and produce tunable oriented electrospun nanofibers scaffolds.
INTRODUCTION
Improving the organization of patterned scaffold helps to provide a better structure which mimics the native Extra Cellular Matrix (ECM) environment [1]. Electrospinning is one of the most utilized techniques to produce electrospun mats in nanoscale diameters with different morphologies and structures of nanofibers. In this process, a positively charged polymer solution jet is drawn through a needle by applying a high voltage electrostatic force, then nanofibers are collected over a grounded metallic collector. In electrospinning process collectors have a very important role to change the structure of nanofibers in the nanoweb. Usually, in the electrospinning process, the nanofibers are collected randomly on the flat collectors. [2] Different collector types with different designs such as static plate, rotating drum, parallel electrode, rotating disc, etc. which have been developed [3, 4]. Depending on collector type, nanofibers orientation can be changed from totally random to highly oriented arrangement [5, 6]. Generally, collectors are divided into two groups, static and rotating collectors. Rotating collectors are mostly based on rotating drum or rotating disk. To use rotating collector in electrospinning process, mandrel must be in the very high speed up to thousands of rpm. Hence, fiber breakage might be occurred. Moreover, the difficulty of detaching the mat and the presence of extra rotating engine can be problematic in the whole process. On the other hand, static collector because of the electrostatic field profile, the jet stretches itself across the gap towards the electrodes which may leads to produce aligned nanofibers. The advantages of these collectors over rotating collectors are easy detachment of mat from the collector and achievement of aligned and unidirectional oriented fibers. Laboratory of Textile Physics and Mechanics (LPMT) of the University of Haute Alsace has been focused on nanofibers' orientation and structure for several years. In the previous work, it has been demonstrated the potential
of 3D printing technology when it is combined with an electrospinning method to produce highly oriented 3D polymeric scaffolds in nanoscale diameter as a novel method. [7] In this work, a new method is investigated to produce highly oriented nanofibers using patterned collector as a new method which is under the patent process.
MATERIALS AND METHODS Scaffold fabrication
The polymeric solution is composed of PA-6 and formic acid as a solvent. The 20 wt% concentration solution was stirred magnetically for at least 24 hours at 50 °C. Fabrication of advanced collectors using new method was done. Afterwards, PA-6 (20 wt%), with the mentioned parameters reported in table I, was electrospun over the patterned collectors by electrospinning machine designed and built in LPMT [8]. The patterned scaffolds on the collectors were achieved with an average fiber diameter of 200 nm. The morphological properties of nanofibers in the produced scaffolds were examined by SEM and ImageJ software on the basis of 30 measurements.
TABLE I. The electrospinning parameters for PA-6 20 wt% on the patterned collectors
Concentration (wt %) 20 Applied voltage (kV) 30 Distance (cm) 20 Needle gauge (mm × mm) 0.45 Feed rate (ml/h) 0.1 Average diameter (nm) 200 The electrospinning was performed on the fabricated collector and the morphological characterization was investigated. To estimate the local orientation of nanofibers, ImageJ software has been used. It evaluates the local orientation and isotropic properties such as coherency of every pixel of the image. The coherency parameter C is defined as the ratio between 0 and 1, with 1 indicating highly oriented structures and 0 indicating isotropic areas.
RESULTS AND DISCUSSION
templates made of nanofibers with alternative pattern of oriented and non-oriented area.
FIGURE 1. Oriented and non-oriented parts 40X (a), magnification 125X (b), and oriented nanofibers (c) According to the orientation measurement results obtained thanks to by ImageJ software, the feasibility of a new generation of collector to obtain highly oriented nanofibers has been proven, presented in table II.
FIGURE 2. ImageJ analysis, significant differences between two parts in a sample
Fig. 2 presents two different parts in the same sample which proves the significant difference in the case of orientation. The oriented nanofibers are mostly organized at the angle of 89.12° with coherency of 0.948 which is near 1. On the contrary, the coherency of random nanofibers on the other part, is approximately 0.1, as it is presented in table II.
TABLE II. orientation and coherency of produced random and oriented nanofibers
Patterned collector Orientation Coherency
Oriented nanofibers -89.12° 0.948 Random nanofibers -19.79° 0.127
According to the recent studies, achieving these rate of orientation with the static collector is promising for the targeted application.
CONCLUSION
This work has investigated the potential of a new generation of collectors in the electrospinning process to produce highly oriented nanofibers in electrospun nanoweb. The obtained results without using any dynamic collectors in the terms of orientation is unique and promising.
KEYWORDS
Electrospinning, Nanofibers, Polyamide 6, Orientation, imageJ
REFERENCES
[1] Li, Wan-Ju, et al. "Electrospun nanofibrous structure:
a novel scaffold for tissue engineering." Journal of biomedical materials research 60.4 (2002): 613-621. [2] Vaquette, Cedryck, and Justin John Cooper-White. "Increasing electrospun scaffold pore size with tailored collectors for improved cell penetration." Acta Biomaterialia 7.6 (2011): 2544-2557.[3] Teo, W. E., and S. Ramakrishna. "A review on electrospinning design and nanofibre assemblies." Nanotechnology 17.14 (2006): R89. [4] Shah Hosseini N, Bölgen N, Yetkin D, Yılmaz N Ş, Khenoussi N, Adolphe D, Yenne Heitter, Hekmati A H, Schacher L ‘’ Novel Patterned 3D Electrospun Scaffolds and Their Effect on Cartilage Cell Attachment’’, Biomedical Electrospun Materials & Applications (BEMA) conference,Mulhouse, France, December 2014 [5] Lavielle, Nicolas, et al. "Structuring and Molding of Electrospun Nanofibers: Effect of Electrical and Topographical Local Properties of Micro‐Patterned Collectors." Macromolecular Materials and Engineering 297.10 (2012): 958-968.
[6] Wu, Yiquan, et al. "Template-assisted assembly of electrospun fibers."Polymer 51.14 (2010): 3244-3248. [7] Shah Hosseini N, Khenoussi N, Adolphe D, Hekmati A H, Schacher L, Bölgen N, ‘’ Producing electrospun 3d scaffold by using 3d collectors for controlling cell response’’, The Fiber Society Meeting and Technical Conference, Philadelphia, Pennsylvania, USA, 2014 Fall [8] Khenoussi, N., L. Schacher, and D. C. Adolphe. "Nanofiber production: study and development of electrospinning device." Experimental Techniques 36.2 (2012): 32-39.
