Special Issue "Fibers for Biomedical Applications"

A special issue of Fibers (ISSN 2079-6439).

Deadline for manuscript submissions: closed (31 May 2015)

Special Issue Editor

Guest Editor
Dr. Jingwei Xie

Department of Surgery-Transplant and Mary & Dick Holland Regenerative Medicine Program, University of Nebraska Medical Center, Omaha, NE 68198-5965, USA
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Special Issue Information

Dear Colleagues,

In the past decade, there has been a significant increase in the use of nanofibers for biomedical applications. Among the fabrication techniques, electrospinning is a remarkably simple and versatile technique that can generate one-dimensional nanofibrous materials. It has been exploited for almost a century to process materials into nanofibers with controllable compositions, diameters, alignment, orders, and structures. Owing to its high porosity and the large surface area to volume ratio, electrospun nanofibers can serve as an ideal substrate to mimic the 3D architecture of extracellular matrix. Biological molecules can be readily incorporated to the nanofibers to elicit certain biological functions during the electrospinning process. In addition, post-processing can also render electropsun nanofibers new properties. Because of these attributes, electrospun nanofibers have been used as scaffolds for tissue engineering and regenerative medicine, as vehicles for controlled and/or sustained local drug delivery, as dressings for wound coverage, as sensing probes for diagnosis and detection, and as substrates for regulating cell behaviors.

It is my pleasure to invite you to submit a manuscript for this Special Issue. Full papers, communications, feature articles, and reviews are all welcome.

Dr. Jingwei Xie
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Fibers is an international peer-reviewed open access quarterly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 350 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.


Keywords

  • electrospinning
  • nanofibers
  • tissue engineering
  • regenerative medicine
  • tissue regeneration
  • biosensing
  • drug delivery
  • controlled release
  • cell response
  • wound dressing

Published Papers (5 papers)

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Research

Open AccessArticle Influence of pH on Morphology and Structure during Hydrolytic Degradation of the Segmented GL-b-[GL-co-TMC-co-CL]-b-GL Copolymer
Fibers 2015, 3(3), 348-372; doi:10.3390/fib3030348
Received: 24 July 2015 / Accepted: 8 September 2015 / Published: 15 September 2015
Cited by 4 | PDF Full-text (1660 KB) | HTML Full-text | XML Full-text
Abstract
Hydrolytic degradation in media having a continuous variation of pH from 2 to 12 was studied for a copolymer having two polyglycolide hard blocks and a middle soft segment constituted by glycolide, trimethylene carbonate, and ɛ-caprolactone units. The last units were susceptible to
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Hydrolytic degradation in media having a continuous variation of pH from 2 to 12 was studied for a copolymer having two polyglycolide hard blocks and a middle soft segment constituted by glycolide, trimethylene carbonate, and ɛ-caprolactone units. The last units were susceptible to cross-linking reactions by γ irradiation that led to an increase of the molecular weight of the sample. Nevertheless, the susceptibility to hydrolytic degradation was enhanced with respect to non-irradiated samples and consequently such samples were selected to analyze the degradation process through weight loss measurements and the evaluation of changes on molecular weight, morphology, and SAXS patterns. Results reflected the different hydrolytic mechanisms that took place in acid and basic media and the different solubilization of the degradation products. Thus, degradation was faster and solubilization higher in the basic media. In this case, fibers showed a high surface erosion and the formation of both longitudinal and deep circumferential cracks that contrasted with the peeling process detected at intermediate pHs (from 6 to 8) and the absence of longitudinal cracks at low pHs. SAXS measurements indicated that degradation was initiated through the hydrolysis of the irregular molecular folds placed on the amorphous interlamellar domains but also affected lamellar crystals at the last stages. Subsequent heating processes performed with degraded samples were fundamental to reveal the changes in microstructure that occurred during degradation and even the initial lamellar arrangement. In particular, the presence of interfibrillar domains and the disposition of lamellar domains at different levels along the fiber axis for a determined cross-section were evidenced. Full article
(This article belongs to the Special Issue Fibers for Biomedical Applications)
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Open AccessArticle Fabrication and Evaluation of Multilayer Nanofiber-Hydrogel Meshes with a Controlled Release Property
Fibers 2015, 3(3), 296-308; doi:10.3390/fib3030296
Received: 4 June 2015 / Accepted: 14 July 2015 / Published: 17 July 2015
Cited by 2 | PDF Full-text (521 KB) | HTML Full-text | XML Full-text
Abstract
Controlled release drug delivery systems enable the sustained release of bioactive molecules, and increase bioavailability over an extended length of time. Biocompatible and biodegradable materials such as polycaprolactone (PCL) nanofibers and alginate hydrogel play a significant role in designing controlled release systems. Prolonged
[...] Read more.
Controlled release drug delivery systems enable the sustained release of bioactive molecules, and increase bioavailability over an extended length of time. Biocompatible and biodegradable materials such as polycaprolactone (PCL) nanofibers and alginate hydrogel play a significant role in designing controlled release systems. Prolonged release of bioactive molecules is observed when these polymer materials are used as matrices independently. However, there has not been a report in the literature that shows how different molecules are released at various rates over time. The goal of this study is to demonstrate a novel drug delivery system that has a property of releasing designated drugs at various rates over a defined length of time. We fabricated multilayer nanofiber-hydrogel meshes using electrospun PCL nanofiber and alginate hydrogel, and evaluated their controlled release properties. The multilayer meshes are composed of sandwiched layers of alternating PCL nanofibers and alginate hydrogel. Adenosine triphosphate (ATP), encapsulated in the designated hydrogel layers, is used as a mock drug for the release study. The exposed top layer of the meshes demonstrates a dramatically higher burst release and shorter release time compared to the deeper layers. Such properties of the different layers within the meshes can be employed to achieve the release of multiple drugs at different rates over a specified length of time. Full article
(This article belongs to the Special Issue Fibers for Biomedical Applications)
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Open AccessArticle Comparison of Engineered Peptide-Glycosaminoglycan Microfibrous Hybrid Scaffolds for Potential Applications in Cartilage Tissue Regeneration
Fibers 2015, 3(3), 265-295; doi:10.3390/fib3030265
Received: 1 June 2015 / Revised: 10 July 2015 / Accepted: 10 July 2015 / Published: 17 July 2015
Cited by 1 | PDF Full-text (992 KB) | HTML Full-text | XML Full-text
Abstract
Advances in tissue engineering have enabled the ability to design and fabricate biomaterials at the nanoscale that can actively mimic the natural cellular environment of host tissue. Of all tissues, cartilage remains difficult to regenerate due to its avascular nature. Herein we have
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Advances in tissue engineering have enabled the ability to design and fabricate biomaterials at the nanoscale that can actively mimic the natural cellular environment of host tissue. Of all tissues, cartilage remains difficult to regenerate due to its avascular nature. Herein we have developed two new hybrid polypeptide-glycosaminoglycan microfibrous scaffold constructs and compared their abilities to stimulate cell adhesion, proliferation, sulfated proteoglycan synthesis and soluble collagen synthesis when seeded with chondrocytes. Both constructs were designed utilizing self-assembled Fmoc-protected valyl cetylamide nanofibrous templates. The peptide components of the constructs were varied. For Construct I a short segment of dentin sialophosphoprotein followed by Type I collagen were attached to the templates using the layer-by-layer approach. For Construct II, a short peptide segment derived from the integrin subunit of Type II collagen binding protein expressed by chondrocytes was attached to the templates followed by Type II collagen. To both constructs, we then attached the natural polymer N-acetyl glucosamine, chitosan. Subsequently, the glycosaminoglycan chondroitin sulfate was then attached as the final layer. The scaffolds were characterized by Fourier transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), atomic force microscopy and scanning electron microscopy. In vitro culture studies were carried out in the presence of chondrocyte cells for both scaffolds and growth morphology was determined through optical microscopy and scanning electron microscopy taken at different magnifications at various days of culture. Cell proliferation studies indicated that while both constructs were biocompatible and supported the growth and adhesion of chondrocytes, Construct II stimulated cell adhesion at higher rates and resulted in the formation of three dimensional cell-scaffold matrices within 24 h. Proteoglycan synthesis, a hallmark of chondrocyte cell differentiation, was also higher for Construct II compared to Construct I. Soluble collagen synthesis was also found to be higher for Construct II. The results of the above studies suggest that scaffolds designed from Construct II be superior for potential applications in cartilage tissue regeneration. The peptide components of the constructs play an important role not only in the mechanical properties in developing the scaffolds but also control cell adhesion, collagen synthesis and proteoglycan synthesis capabilities. Full article
(This article belongs to the Special Issue Fibers for Biomedical Applications)
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Open AccessArticle Investigating the Influence of Extracellular Matrix and Glycolytic Metabolism on Muscle Stem Cell Migration on Their Native Fiber Environment
Fibers 2015, 3(3), 253-264; doi:10.3390/fib3030253
Received: 2 June 2015 / Accepted: 8 July 2015 / Published: 16 July 2015
PDF Full-text (383 KB) | HTML Full-text | XML Full-text
Abstract
The composition of the extracellular matrix (ECM) of skeletal muscle fibers is a unique environment that supports the regenerative capacity of satellite cells; the resident stem cell population. The impact of environment has great bearing on key properties permitting satellite cells to carry
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The composition of the extracellular matrix (ECM) of skeletal muscle fibers is a unique environment that supports the regenerative capacity of satellite cells; the resident stem cell population. The impact of environment has great bearing on key properties permitting satellite cells to carry out tissue repair. In this study, we have investigated the influence of the ECM and glycolytic metabolism on satellite cell emergence and migration—two early processes required for muscle repair. Our results show that both influence the rate at which satellite cells emerge from the sub-basal lamina position and their rate of migration. These studies highlight the necessity of performing analysis of satellite behavior on their native substrate and will inform on the production of artificial scaffolds intended for medical uses. Full article
(This article belongs to the Special Issue Fibers for Biomedical Applications)
Open AccessArticle Electrospun Scaffolds from Low Molecular Weight Poly(ester amide)s Based on Glycolic Acid, Adipic Acid and Odd or Even Diamines
Fibers 2015, 3(2), 151-172; doi:10.3390/fib3020151
Received: 13 March 2015 / Accepted: 4 May 2015 / Published: 12 May 2015
PDF Full-text (1239 KB) | HTML Full-text | XML Full-text
Abstract
Electrospinning of regular poly(ester amide)s (PEAs) constituted by glycolic acid, adipic acid and diamines with five and six carbon atoms has been carried out. Selected PEAs were constituted by natural origin products and could be easily prepared by a polycondensation method that avoids
[...] Read more.
Electrospinning of regular poly(ester amide)s (PEAs) constituted by glycolic acid, adipic acid and diamines with five and six carbon atoms has been carried out. Selected PEAs were constituted by natural origin products and could be easily prepared by a polycondensation method that avoids tedious protection and deprotection steps usually required for obtaining polymers with a regular sequence. Nevertheless, the synthesis had some limitations that mainly concerned the final low/moderate molecular weight that could be attained. Therefore, it was considered interesting to evaluate if electrospun scaffolds could still be prepared taking also advantage of the capability of PEAs to establish intermolecular hydrogen bonds. Results indicated that the crucial factor was the control of polymer concentration in the electrospun solution, being necessary that this concentration was higher than 40% (w/v). The PEA with the lowest molecular weight (Mw close to 8000 g/mol) was the most appropriate to obtain electrospun samples with a circular cross-section since higher molecular sized polymers show solvent retention problems derived from the high viscosity of the electrospun solution that rendered ribbon-like morphologies after the impact of fibers into the collector. The studied PEAs were semicrystalline and biodegradable, as demonstrated by calorimetric and degradation studies. Furthermore, the new scaffolds were able to encapsulate drugs with anti-inflammatory and bacteriostatic activities like ketoprofen. The corresponding release and bactericide activity was evaluated in different media and against different bacteria. Finally, biocompatibility was demonstrated using both fibroblast and epithelial cell lines. Full article
(This article belongs to the Special Issue Fibers for Biomedical Applications)
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