Wet-spinning of magneto-responsive helical chitosan microfibers

Abstract

<jats:p>Helical structures can be found in nature at various length scales ranging from the molecular level to the macroscale. Due to their ability to store mechanical energy and to optimize the accessible surface area, helical shapes contribute particularly to motion-driven processes and structural reinforcement. Due to these special features, helical fibers have become highly attractive for biotechnological and tissue engineering applications. However, there are only a few methods available for the production of biocompatible helical microfibers. Given that, we present here a simple technique for the fabrication of helical chitosan microfibers with embedded magnetic nanoparticles. Composite fibers were prepared by wet-spinning and coagulation in an ethanol bath. Thereby, no toxic components were introduced into the wet-spun chitosan fibers. After drying, the helical fibers had a diameter of approximately 130 µm. Scanning electron microscopy analysis of wet-spun helices revealed that the magnetic nanoparticles agglomerated into clusters inside the fiber matrix. The helical constructs exhibited a diameter of approximately 500 µm with one to two windings per millimeter. Due to their ferromagnetic properties they are easily attracted to a permanent magnet. The results from the tensile testing show that the helical chitosan microfibers exhibited an average Young’s modulus of 14 MPa. By taking advantage of the magnetic properties of the feedstock solution, the production of the helical fibers could be automated. The fabrication of the helical fibers was achieved by utilizing the magnetic properties of the feedstock solution and winding the emerging fiber around a rotating magnetic collector needle upon coagulation. In summary, our helical chitosan microfibers are very attractive for future use in magnetic tissue engineering or for the development of biocompatible actuator systems.</jats:p>

Manufacturing of animal products by the assembly of microfabricated tissues

“…Non cell-laden fibers are used as scaffolds which require to be biocompatible, biodegradable with a structural condition for cell–cell and cell–material interactions [ 4 ]. Various biomaterials are used as polymeric solutions such as poly(lactide-co-glycolide) (PLGA) [ 6 ], chitosan [ 7 , 8 ], and alginate [ 9 , 10 ]. These wet spun fibers show porous structures with availability for cell adhesion and proliferation.…”

“…Also, the fabricated tissues need to fulfill the morphological and functional characteristics of in vivo tissue are required; e.g., the animal meat tissue has highly aligned muscle fibers and well-distributed fat. For the fabrication of tissue-based animal products, recent technical advances in microfabrication and tissue engineering have led to techniques such as spinning [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], cell layering [23][24][25][26][27][28], and 3D bioprinting to mimic intrinsic characteristics of in vivo animal tissue. In this review, we provide an overview of recent technological breakthroughs in the fabrication of tissue-based animal products such as cultured meat and leather-like materials.…”

Tunable Spun Fiber Constructs in Biomedicine: Influence of Processing Parameters in the Fibers’ Architecture

“…Stretching and chemical crosslinking also influences the Young's modulus of the fibers. In fact, those parameters, along with post-drying, can tune the mechanical properties of the helical fibers, achieving mechanical features resembling tissue environments [21].…”

“…Among these approaches, electrospinning and wet-spinning are the ones considered most relevant for biomedical uses, particularly for drug delivery systems, since they allow to control fiber production in such a way that complex fiber structures with different organizations and architectures can be attained: (1) side-by-side fibers [18,19], (2) porous [20], (3) helical [21], (4) core-shell [22], (5) hollow [23], (6) tri-axial [24], (6) multilayered [25]. Such morphologies require a precise control of processing parameters.…”

Physically Switchable Antimicrobial Surfaces and Coatings: General Concept and Recent Achievements

“…Such magneto-responsive coatings can be easily realized through matrix coating doped with magnetic nanoparticles. Simpler and scalable techniques, such as in situ crystallization and freeze-drying, co-precipitation, molding, and solvent-casting techniques [115][116][117][118][119] provide an elegant strategy for the creation of smart, magneto-activated coatings. Subsequent utilization of the external magnetic field results in significant surface morphology changing, providing an opportunity to create and switch proteins adhesivity or recreate dynamically cell-repellent surfaces.…”