Aligned Fiber Scaffolds Research Articles

Biomimetic electrospun PVDF/self-assembling peptide piezoelectric scaffolds for neural stem cell transplantation in neural tissue engineering.

Piezoelectric materials can provide in situ electrical stimulation without external chemical or physical support, opening new frontiers for future bioelectric therapies. Polyvinylidene fluoride (PVDF) possesses piezoelectricity and biocompatibility, making it an electroactive biomaterial capable of enhancing bioactivity through instantaneous electrical stimulation, which indicates significant potential in tissue engineering. In this study, we developed electroactive and biomimetic scaffolds made of electrospun PVDF and self-assembling peptides (SAPs) to enhance stem cell transplantation for spinal cord injury regeneration. We investigated the morphology and crystalline polymorphs of the electrospun scaffolds. Morphological studies demonstrated the benefit of using mixed sodium dodecyl sulfate (SDS) and SAPs as additives to form thinner, uniform, and defect-free fibers. Regarding electroactive phases, β and γ phases-evidence of electroactivity-were predominant in aligned scaffolds and scaffolds modified with SDS and SAPs. In vitro studies showed that neural stem cells (NSCs) seeded on electrospun PVDF with additives exhibited desirable proliferation and differentiation compared to the gold standard. Furthermore, the orientation of the fibers influenced scaffold topography, resulting in a higher degree of cell orientation in fiber-aligned scaffolds compared to randomly oriented ones.

Neuro-regenerative behavior of adipose-derived stem cells in aligned collagen I hydrogels.

Peripheral nerve injuries persist as a major clinical issue facing the US population and can be caused by stretch, laceration, or crush injuries. Small nerve gaps are simple to treat, and the nerve stumps can be reattached with sutures. In longer nerve gaps, traditional treatment options consist of autografts, hollow nerve guidance conduits, and, more recently, manufactured fibrous scaffolds. These manufactured scaffolds often incorporate stem cells, growth factors, and/or extracellular matrix (ECM) proteins to better mimic the native environment but can have issues with homogenous cell distribution or uniformly oriented neurite outgrowth in scaffolds without fibrous alignment. Here, we utilize a custom device to fabricate collagen I hydrogels with aligned fibers and encapsulated adipose-derived mesenchymal stem cells (ASCs) for potential use as a peripheral nerve repair graft. Initial results of our scaffold system revealed significantly less cell viability in higher collagen gel concentrations; 3mg/mL gels showed 84.8±7.3% viable cells, compared to 6mg/mL gels viability of 76.7±9.5%. Mechanical testing of the 3mg/mL gels showed a Young's modulus of 6.5±0.8kPa nearly matching 7.45kPa known to support Schwann cell migration. Further analysis of scaffolds coupled with stretching in vitro revealed heightened angiogenic and factor secretion, ECM deposition, fiber alignment, and dorsal root ganglia (DRG) neurite outgrowth along the axis of fiber alignment. Our platform serves as an in vitro testbed to assess neuro-regenerative potential of ASCs in aligned collagen fiber scaffolds and may provide guidance on next-generation nerve repair scaffold design.

Electrospun decellularized extracellular matrix scaffolds promote the regeneration of injured neurons

Traumatic injury to the spinal cord (SCI) causes the transection of neurons, formation of a lesion cavity, and remodeling of the microenvironment by excessive extracellular matrix (ECM) deposition and scar formation leading to a regeneration-prohibiting environment. Electrospun fiber scaffolds have been shown to simulate the ECM and increase neural alignment and neurite outgrowth contributing to a growth-permissive matrix. In this work, electrospun ECM-like fibers providing biochemical and topological cues are implemented into a scaffold to represent an oriented biomaterial suitable for the alignment and migration of neural cells in order to improve spinal cord regeneration. The successfully decellularized spinal cord ECM (dECM), with no visible cell nuclei and dsDNA content < 50 ng/mg tissue, showed preserved ECM components, such as glycosaminoglycans and collagens. Serving as the biomaterial for 3D printer-assisted electrospinning, highly aligned and randomly distributed dECM fiber scaffolds (< 1 µm fiber diameter) were fabricated. The scaffolds were cytocompatible and supported the viability of a human neural cell line (SH-SY5Y) for 14 days. Cells were selectively differentiated into neurons, as confirmed by immunolabeling of specific cell markers (ChAT, Tubulin ß), and followed the orientation given by the dECM scaffolds. After generating a lesion site on the cell-scaffold model, cell migration was observed and compared to reference poly-ε-caprolactone fiber scaffolds. The aligned dECM fiber scaffold promoted the fastest and most efficient lesion closure, indicating superior cell guiding capabilities of dECM-based scaffolds. The strategy of combining decellularized tissues with controlled deposition of fibers to optimize biochemical and topographical cues opens the way for clinically relevant central nervous system scaffolding solutions.

Integrated Manufacturing of Suspended and Aligned Nanofibrous Scaffold for Structural Maturation and Synchronous Contraction of HiPSC-Derived Cardiomyocytes.

Electrospun nanofiber constructs represent a promising alternative for mimicking the natural extracellular matrix in vitro and have significant potential for cardiac patch applications. While the effect of fiber orientation on the morphological structure of cardiomyocytes has been investigated, fibers only provide contact guidance without accounting for substrate stiffness due to their deposition on rigid substrates (e.g., glass or polystyrene). This paper introduces an in situ fabrication method for suspended and well aligned nanofibrous scaffolds via roller electrospinning, providing an anisotropic microenvironment with reduced stiffness for cardiac tissue engineering. A fiber surface modification strategy, utilizing oxygen plasma treatment combined with sodium dodecyl sulfate solution, was proposed to maintain the hydrophilicity of polycaprolactone (PCL) fibers, promoting cellular adhesion. Human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes (CMs), cultured on aligned fibers, exhibited an elongated morphology with extension along the fiber axis. In comparison to Petri dishes and suspended random fiber scaffolds, hiPSC-CMs on suspended aligned fiber scaffolds demonstrated enhanced sarcomere organization, spontaneous synchronous contraction, and gene expression indicative of maturation. This work demonstrates the suspended and aligned nano-fibrous scaffold provides a more realistic biomimetic environment for hiPSC-CMs, which promoted further research on the inducing effect of fiber scaffolds on hiPSC-CMs microstructure and gene-level expression.

Silk-inspired fiber implant with multi-cues enhanced bionic microenvironment for promoting peripheral nerve repair

Successful repair and desirable functional recovery of large-gap nerve injuries using artificial nerve implants remains a significant clinical challenge. The beneficial bionic microenvironment within scaffolds can significantly promote the outgrowth of newborn nerve tissues after implantation. Herein, we developed an aligned silk-inspired fiber scaffold (RGD@ASFFs) with a synergistic effect of an extracellular matrix mimicking physical cues and RGD (Arg-Gly-Asp) signals to provide an enhanced cell-friendly microenvironment for repairing large-gap peripheral nerve injuries. The topographic alignment of the methacrylated silk fibroin electrospun fibers effectively facilitated axonal guidance and oriented Schwann cell growth. Importantly, the mechanical cue combined with cell adhesion signals provided by RGD peptides further triggered enriched myelination of Schwann cells by nuclear translocation of Yes-associated protein 1 (YAP) to secrete neurotrophins to support axonal growth. Moreover, benefiting from improved neuronal extension and re-myelination, promising motor function recovery in vivo was achieved by RGD@ASFFs, which is comparable to that of autografts. Thus, the design of this engineered bionic scaffold is a powerful strategy for peripheral nerve defect repair.

Silver nanowire loaded poly(ε-caprolactone) nanocomposite fibers as electroactive scaffolds for skeletal muscle regeneration

Volumetric muscle loss (VML) due to trauma and tumor removal operations affects millions of people every year. Although skeletal muscle has a natural repair mechanism, it cannot provide self-healing above a critical level of VML. In this study, nanocomposite aligned fiber scaffolds as support materials were developed for volumetric skeletal muscle regeneration. For this purpose, silver nanowire (Ag NW) loaded poly(ε-caprolactone) (PCL) nanocomposite fiber scaffolds (PCL-Ag NW) were prepared to mimic the aligned electroactive structure of skeletal muscle and provide topographic and conductive environment to modulate cellular behavior and orientation. A computer-aided rotational wet spinning (RWS) system was designed to produce high-yield fiber scaffolds. Nanocomposite fiber bundles with lengths of 50 cm were fabricated via this computer-aided RWS system. The morphological, chemical, thermal properties and biodegradation profiles of PCL and PCL-Ag NW nanocomposite fibers were characterized in detail. The proliferation behavior and morphology of C2C12 mouse myoblasts were investigated on PCL and PCL-Ag NW nanocomposite fibrous scaffolds with and without electrical stimulation. Significantly enhanced cell proliferation was observed on PCL-Ag NW nanocomposite fibers compared to neat PCL fibers with electrical stimulations of 1.5 V, 3 V and without electrical stimulation.

Fabrication of a Simultaneous Highly Transparent and Highly Hydrophobic Fibrous Films

This paper discusses the fabrication and characterization of electrospun nanofiber scaffolds made of polystyrene (PS). The scaffolds were characterized in terms of their basis material molecular weight, fiber diameter distribution, contact angles, contact angle hysteresis, and transmittance. We propose an aligned electrospun fiber scaffold using an alignment tool (alignment jig) for the fabrication of highly hydrophobic (θW &gt; 125°) and highly transparent (T &gt; 80.0%) films. We fabricated the alignment jig to align the electrospun fibers parallel to each other. The correlation between the water contact angles and surface roughness of the aligned electrospun fibers was investigated. We found that the water contact angle increased as the surface roughness was increased. Therefore, the hydrophobic properties of the aligned electrospun fibers were enhanced by increasing the surface roughness. With the change in the electrospinning mode to produce aligned fibers rather than randomly distributed fibers, the transmittance of the aligned electrospun fibers increased. The increase in the porous area, leading to better light transmittance in comparison to randomly distributed light scattering through the aligned electrospun fibers increased with the fibers. Through the above investigation of electrospinning parameters, we obtained the simultaneous transparent (&gt;80%) and hydrophobic (θW &gt; 140°) electrospun fiber scaffold. The aligned electrospun fibers of PS had a maximum transmittance of 91.8% at the electrospinning time of 10 s. The water contact angle (WCA) of the aligned electrospun fibers increased from 77° to 141° as the deposition time increased from 10 s to 40 s. The aligned fibers deposited at 40 s showed highly hydrophobic characteristics (θW &gt; 140°).

Harnessing Fiber Diameter-Dependent Effects of Myoblasts Toward Biomimetic Scaffold-Based Skeletal Muscle Regeneration.

Regeneration of skeletal muscles is limited in cases of volumetric muscle loss and muscle degenerative diseases. Therefore, there is a critical need for developing strategies that provide cellular and structural support for skeletal muscle regeneration. In the present work, a bioengineered cell niche composed of mechanically competent aligned polyester fiber scaffolds is developed to mimic the oriented muscle fiber microenvironment by electrospinning poly(lactide-co-glycolide) (PLGA) using a custom-designed rotating collector with interspaced parallel blades. Aligned fiber scaffolds with fiber diameters ranging from 335 ± 154 nm to 3013 ± 531 nm are characterized for their bioactivities in supporting growth and differentiation of myoblasts. During in vitro culture, polymeric scaffolds with larger fiber diameter support enhanced alignment, growth, and differentiation of myoblasts associated with phosphorylation of p38 MAPK and upregulated expression of myogenin and myosin heavy chain. In vivo studies using a dystrophin-deficient mdx mouse model show that optimized fiber scaffolds seeded with primary myoblasts result in formation of dystrophin-positive myofibers network in tibialis anterior muscles. Collectively, these experiments provide critical insights on harnessing interactions between muscle cells and engineered fiber matrices to develop effective biomaterials for accelerated muscle regeneration.

Characterization of extracellular matrix modified poly(ε-caprolactone) electrospun scaffolds with differing fiber orientations for corneal stroma regeneration.

Alternatives to donor cornea transplantation based on tissue engineering are desirable to overcome the current severe donor tissue shortage. Many natural polymers have good biological properties but poor mechanical properties and degradation resistance; while synthetic polymers have good mechanical properties but do not contain biochemical molecules normally found in the real tissue. In addition, both fiber orientation and composition play a key role in dictating cell behavior within a scaffold. In this study, the effect on corneal stromal cells of adding decellularized corneal extracellular matrix (ECM) to an electrospun polymer with differing fiber organizations was explored. Electrospun matrices were generated using polycaprolactone (PCL) and PCL combined with ECM and electrospun into random, radial and perpendicularly aligned fiber scaffolds. Human corneal stromal cells were seeded onto these scaffolds and the effect of composition and orientation on the cells phenotype was assessed. Incorporation of ECM into PCL increased hydrophilicity of scaffolds without an adverse effect on Young's modulus. Cells seeded on these matrices adopted different morphologies that followed the orientation of the fibers. Keratocyte markers were increased in all types of scaffolds compared to tissue culture plastic. Scaffolds with radial and perpendicularly aligned fibers promoted enhanced cell migration. Aligned scaffolds with incorporated ECM show promise for their use as cell-free implants that promote endogenous repopulation by neighboring cells.

Glycosaminoglycan functionalization of electrospun scaffolds enhances Schwann cell activity

Nerve fibers of the peripheral nervous system (PNS) have a remarkable ability to regenerate up to an almost complete recovery of normal function following a crush or a Sunderland Type II injury. This process is governed by glial cells, known as Schwann cells, through their unique capacity to dedifferentiate into cells that drive the healing process. Despite that many progresses have occurred in restorative medicine and microsurgery, the regenerative process after a severe lesion of a major nerve trunk (e.g., Sunderland Types III-V) is often incomplete and functional recovery is unsatisfactory. In this aspect, it is known that glycosaminoglycans (GAGs) of the extracellular matrix are involved in proliferation, synaptogenesis, neural plasticity, and regeneration of the PNS. Here, we developed poly(caprolactone) (PCL) fibrous scaffolds functionalized with GAGs, which allowed us to assess their influence on the adhesion, proliferation, and differentiation of Schwann cells. We found that both aligned and random fiber scaffolds functionalized with GAGs resulted in increased cell proliferation on day 1. In addition, aligned functionalized scaffolds also resulted in increased GAG presence on day 1, probably because of cell extracellular matrix (ECM) formation and an increased syndecan-4 expression on day 7. A different modification and activation of Schwann cells in the presence of GAG versus no-GAG scaffolds was underlined by proteomic comparative analysis, where a general downregulation of the expression of intracellular/structural and synthetic proteins was shown on day 7 for GAG-functionalized scaffolds with regard to the nonfunctionalized ones. In conclusion, we have shown that GAG-functionalized scaffolds are effective in modulating Schwann cell behavior in terms of adhesion, proliferation, and differentiation and should be considered in strategies to improve PNS repair. Statement of SignificanceNerve fibers functional recovery following a severe trauma of the Peripheral Nervous System (PNS) still represents a huge challenge for neurosurgery nowadays. In this respect, tissue engineering is committed to develop new constructs able to guide Schwann cells by mimicking the natural extracellular matrix environment. To this purpose, we successfully fabricated polycaprolactone (PCL) scaffolds with two well-defined fiber deposition patterns, functionalized with glycosaminoglycans (GAGs) and assessed for their potential as support for Schwann cells adhesion, growth and differentiation, by both classical biochemistry and LC-MS-based proteomic profiling. By this way, we showed that PCL–GAGs scaffolds could represent a promising artificial substrate that closely mimics the recently established pattern of Schwann cells migration into the regenerating nerve and, therefore, it should be considered in strategies to improve PNS repair.

Injectable, Magnetically Orienting Electrospun Fiber Conduits for Neuron Guidance.

Magnetic electrospun fibers are of interest for minimally invasive biomaterial applications that also strive to provide cell guidance. Magnetic electrospun fibers can be injected and then magnetically positioned in situ, and the aligned fiber scaffolds provide consistent topographical guidance to cells. In this study, magnetically responsive aligned poly-l-lactic acid electrospun fiber scaffolds were developed and tested for neural applications. Incorporating oleic acid-coated iron oxide nanoparticles significantly increased neurite outgrowth, reduced the fiber alignment, and increased the surface nanotopography of the electrospun fibers. After verifying neuron viability on two-dimensional scaffolds, the system was tested as an injectable three-dimensional scaffold. Small conduits of aligned magnetic fibers were easily injected in a collagen or fibrinogen hydrogel solution and repositioned using an external magnetic field. The aligned magnetic fibers provided internal directional guidance to neurites within a three-dimensional collagen or fibrin model hydrogel, supplemented with Matrigel. Neurites growing from dorsal root ganglion explants extended 1.4-3× farther on the aligned fibers compared with neurites extending in the hydrogel alone. Overall, these results show that magnetic electrospun fiber scaffolds can be injected and manipulated with a magnetic field in situ to provide directional guidance to neurons inside an injectable hydrogel. Most importantly, this injectable guidance system increased both neurite alignment and neurite length within the hydrogel scaffold.

High throughput fabrication of curcumin embedded gelatin-polylactic acid forcespun fiber-aligned scaffolds for the controlled release of curcumin

Abstract

Injectable Nanoreinforced Shape-Memory Hydrogel System for Regenerating Spinal Cord Tissue from Traumatic Injury.

Traumatic injury in the central nervous system can lead to loss of functional neurons. Transplantation of neural progenitors is a promising therapeutic strategy. However, infusion of dissociated cells often suffers from low viability, uneven cell distribution, and poor in vivo engraftment that could be reinforced by a better cell delivery system. Here, we develop an injectable composite hydrogel system for use as a minimally invasive treatment of spinal cord injury (SCI) using motor neurons (MNs) derived from embryonic stem cells (ESCs). The composite hydrogel is based on a modified gelatin matrix integrated with shape-memory polymer fibers. The gelatin matrix creates a local microenvironment for cell assembly and also acts as a lubricant during injection through a fine catheter. Notably, shape-memory fiber scaffolds are able to recover to maintain the microstructures even after dramatic deformation from injection operation, providing the necessary support and guidance for motor neuron differentiation. We find that the composite hydrogel with an aligned fiber scaffold greatly improves the viability of ESCs and their differentiation toward MNs both in vitro and in vivo. When transplanted to SCI animals by injection, the ESC-loaded composite hydrogels are identified to significantly enhance tissue regeneration and motor function recovery in mice. With this proof-of-concept study, we believe that the injectable composite hydrogel system provides a promising solution for in vivo cell delivery with minimum invasiveness and can be readily extended to other stem-cell-based regenerative treatments.

Aligned Collagen Scaffolds Enhance Tenogenic Differentiation of Bone Marrow-Derived Stem Cells

Tendon repair remains a formidable challenge in clinic, due to its limited function in long-term recovery. Decellularized native tendon extracellular matrix (ECM), which contains specific bioactive factors and a large number of collagen fibers, seeded with bone marrow-derived stem cells (BMSCs) has been found to promote tendon neogenesis. However, the effect of arrangements of natural collagen fibers on the differentiation of BMSCs remains unclear. Here, we prepared aligned collagen fiber scaffolds from rat tail tendon ECM to investigate the effect of collagen arrangements on the morphology, proliferation and differentiation of rat BMSCs in vitro. It was found that BMSCs were elongated and aligned along the collagen fibers on the aligned collagen fibers. Furthermore, the aligned collagen scaffolds significantly enhanced the expression of tenocyte markers TNMD and THBS4. The results indicated that aligned collagen scaffolds could induce the tenogenesis of BMSCs, which would provide an alternative approach for tendon tissue engineering.

Spatio-temporal release of NGF and GDNF from multi-layered nanofibrous bicomponent electrospun scaffolds

Scaffolds capable of providing dual neurotrophic factor (NTF) delivery with different release kinetics, spatial delivery of NTFs at different loci and topographical guidance are promising for enhanced peripheral nerve regeneration. In this study, we have designed and fabricated multi-layered aligned-fiber scaffolds through combining emulsion electrospinning, sequential electrospinning and high-speed electrospinning (HS-ES) to modulate the release behavior of glial cell line-derived growth factor(GDNF) and nerve growth factor (NGF). GDNF and NGF were incorporated into poly(lactic-co-glycolic acid) (PLGA) fibers and poly(D,L-lactic acid) (PDLLA) fibers, respectively. Aligned fibers were obtained in each layer of multi-layered scaffolds and relatively thick tri-layered and tetra-layered scaffolds with controlled layer thickness were obtained. Their morphology, structure, properties, and the in vitro release of growth factors were examined. Dual and spatio-temporal release of GDNF and NGF with different release kinetics from multi-layered scaffolds was successfully demonstrated. High separation efficiency by PDLLA fibrous barrier layer for spatial neurotrophic factor delivery from both tri-layered scaffolds and tetra-layered scaffolds was achieved.

Development of forcespun fiber-aligned scaffolds from gelatin-zein composites for potential use in tissue engineering and drug release

Abstract

Characterization of poly(lactic acid) melt spun fiber aligned scaffolds prepared with hot pressing method

Aligned fiber scaffolds are known to control cell behavior in vitro due to contact guidance and have potential applications as a cell carrier, ligament substrate, drug loading and release, nerve regeneration, implantable functional muscle, bone repair and meniscus tissue engineering. Aligned fiber scaffolds are often prepared by electrospinning, however in this study, poly(lactic acid) (PLA) melt spun fiber aligned scaffolds were prepared by a hot pressing method using a temperature of 60–180 °C. The hot pressing temperature plays an important role in surface and cross sectional morphology, dimensions, fiber parallel arrangement, thickness, pore diameter, porosity, water absorption and stress. The results indicate that PLA melt spun fiber aligned scaffolds prepared at 60 °C had optimum physical properties for applications in tissue engineering.

Poly(l-lactide) melt spun fiber-aligned scaffolds coated with collagen or chitosan for guiding the directional migration of osteoblasts in vitro.

Aligned fiber scaffolds can mimic the parallel aligned fibrils in the extracellular matrix (ECM) of bones, and thus regulate many cellular behaviors. The aligned scaffolds are usually prepared by a microplate micropatterned method, freeze casting, evaporation, slip casting, ice-templating, plain weaving, and fiber forming techniques. In this study, the melt spinning technology, which has the advantages of a higher spinning speed, solvent-free processing and readily scalable production, was used to prepare poly(l-lactide) (PLLA) melt spun fibers with an average diameter of 70.3 ± 11.4 μm. The fibers were further bonded by 5% PLLA tetrahydrofuran solution to prepare PLLA spun fiber-aligned scaffolds. Collagen and chitosan molecules were coated onto the fibers/into the scaffolds to obtain multiple biochemical and surface aligned topography cues, respectively. The collagen or chitosan-coated PLLA aligned scaffolds could effectively improve the viability, adhesion, length and migration behaviors of osteoblasts in vitro. In particular, the collagen coated aligned scaffold had the largest cell length and the fastest migration rate, with a preferential direction along the fibers. This type of scaffold provides a versatile substrate to control cell behaviors, having great potential for bone regeneration.

Fabrication of macromolecular gradients in aligned fiber scaffolds using a combination of in-line blending and air-gap electrospinning.

The native tendon-bone interface contains a gradient of properties that ensures stability of the joint. Without this transition, failure can occur due to stress concentration at the bone insertion site. Electrospinning is a method commonly used to produce fibrous grafts with gradient properties; however, no current method allows for gradients in the direction of fiber alignment. This work details a novel electrospinning method to produce gradients in the direction of fiber alignment in order to better mimic transitional zones and improve regeneration of the tendon-bone interface. In addition to the biomechanical gradients demonstrated here, this method may also be used to generate gradients of macromolecular, biochemical, and cellular cues with broad potential utility in tissue engineering.

Bioengineered Cell Niche for Skeletal Muscle Regeneration

Skeletal muscles can self-repair minor strains, lacerations, and contusions; however, in cases of volumetric muscle loss and muscle degenerative diseases, tissue fails to regenerate. Current cell-based therapies, such as myoblast transplantation, have significant drawbacks of low survival rates and engraftment efficacy, mainly due to the absence of supportive cell microenvironment. Scaffolds that mimic the natural cell microenvironment provide a robust platform to support cell adhesion, migration, proliferation, and differentiation. Electrospinning is a versatile technology platform used for fabricating the fiber scaffold that mimics the extracellular matrix. Thus, we aim to reconstitute the cell microenvironment through development of aligned fiber scaffolds by electrospinning as oriented muscle fibers create natural microenvironment of myogenic cells. In particular, aligned fiber scaffolds will be optimized in term of mechanical properties and fiber diameters as fiber curvature and mechanical stiffness provide significant physical cues for myogenic cell behaviors. Here, we fabricated and characterized electrospun polyester fiber scaffolds with different diameters from micro-scale to nano-scale. The mechanical properties of the fabricated nanofibers were found to be in the range of contractile muscles as evidenced from atomic force microscopy measurements. With these scaffolds, C2C12 myoblasts were seeded and analyzed for the initial attachment. It was shown that aligned fibers with varying diameters resulted in different responses in cell attachment, indicating the role of cell topography sensing in cell-biomaterial interactions. Current ongoing studies focus on long-term in vitro culture of scaffolds in a custom-made muscle bioreactor emulating the contraction/relaxation of skeletal muscle tissue.