Electrospinning: a fascinating fiber fabrication technique.

Electrospinning: Applications in drug delivery and tissue engineering

Tissue engineering applications commonly encompass the use of three-dimensional (3D) scaffolds to provide a suitable microenvironment for the incorporation of cells or growth factors to regenerate ...

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Three-dimensional scaffolds for tissue engineering applications : role of porosity and pore size

With advances in tissue engineering, the possibility of regenerating injured tissue or failing organs has become a realistic prospect for the first time in medical history. Tissue engineering - the combination of bioactive materials with cells to generate engineered constructs that functionally replace lost and/or damaged tissue - is a major strategy to achieve this goal. One facet of tissue engineering is biofabrication, where three-dimensional tissue-like structures composed of biomaterials and cells in a single manufacturing procedure are generated. Cell-laden hydrogels are commonly used in biofabrication and are termed "bioinks". Hydrogels are particularly attractive for biofabrication as they recapitulate several features of the natural extracellular matrix and allow cell encapsulation in a highly hydrated mechanically supportive three-dimensional environment. Additionally, they allow for efficient and homogeneous cell seeding, can provide biologically-relevant chemical and physical signals, and can be formed in various shapes and biomechanical characteristics. However, despite the progress made in modifying hydrogels for enhanced bioactivation, cell survival and tissue formation, little attention has so far been paid to optimize hydrogels for the physico-chemical demands of the biofabrication process. The resulting lack of hydrogel bioinks have been identified as one major hurdle for a more rapid progress of the field. In this review we summarize and focus on the deposition process, the parameters and demands of hydrogels in biofabrication, with special attention to robotic dispensing as an approach that generates constructs of clinically relevant dimensions. We aim to highlight this current lack of effectual hydrogels within biofabrication and initiate new ideas and developments in the design and tailoring of hydrogels. The successful development of a "printable" hydrogel that supports cell adhesion, migration, and differentiation will significantly advance this exciting and promising approach for tissue engineering.

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25th Anniversary Article: Engineering Hydrogels for Biofabrication

Scaffolds represent important components for tissue engineering. However, researchers often encounter an enormous variety of choices when selecting scaffolds for tissue engineering. This paper aims to review the functions of scaffolds and the major scaffolding approaches as important guidelines for selecting scaffolds and discuss the tissue-specific considerations for scaffolding, using intervertebral disc as an example.

Scaffolding in tissue engineering: general approaches and tissue-specific considerations.

Interest in electrospinning has recently escalated due to the ability to produce materials with nanoscale properties. Electrospun fibers have been investigated as promising tissue engineering scaffolds since they mimic the nanoscale properties of native extracellular matrix. In this review, we examine electrospinning by providing a brief description of the theory behind the process, examining the effect of changing the process parameters on fiber morphology, and discussing the potential applications and impacts of electrospinning on the field of tissue engineering.

Electrospinning of polymeric nanofibers for tissue engineering applications: a review.

Electrospun Poly(ε-caprolactone) Microfiber and Multilayer Nanofiber/Microfiber Scaffolds: Characterization of Scaffolds and Measurement of Cellular Infiltration

This study instituted a unique approach to bone tissue engineering by combining effects of mechanical stimulation in the form of fluid shear stresses and the presence of bone-like extracellular matrix (ECM) on osteodifferentiation. Rat marrow stromal cells (MSCs) harvested from bone marrow were cultured on titanium (Ti) fiber mesh discs for 12 days in a flow perfusion system to generate constructs containing bone-like ECM. To observe osteodifferentiation and bone-like matrix deposition, these decellularized constructs and plain Ti fiber meshes were seeded with MSCs (Ti/ECM and Ti, respectively) and cultured in the presence of fluid shear stresses either with or without the osteogenic culture supplement dexamethasone. The calcium content, alkaline phosphatase activity, and osteopontin secretion were monitored as indicators of MSC differentiation. Ti/ECM constructs demonstrated a 75-fold increase in calcium content compared with their Ti counterparts after 16 days of culture. After 16 days, the presence of dexamethasone enhanced the effects of fluid shear stress and the bone-like ECM by increasing mineralization 50-fold for Ti/ECM constructs; even in the absence of dexamethasone, the Ti/ECM constructs exhibited approximately a 40-fold increase in mineralization compared with their Ti counterparts. Additionally, denatured Ti/ECM* constructs demonstrated a 60-fold decrease in calcium content compared with Ti/ECM constructs after 4 days of culture. These results indicate that the inherent osteoinductive potential of bone-like ECM along with fluid shear stresses synergistically enhance the osteodifferentiation of MSCs with profound implications on bone-tissue-engineering applications.

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In vitro generated extracellular matrix and fluid shear stress synergistically enhance 3D osteoblastic differentiation

Metallic stents have been widely used in coronary angioplasty. Here, the authors develop a resorbable self-expanding stent from polymeric elastomers with high mechanical strength for coronary applications.

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Upma Sharma

Papers

Electrospinning of polymeric nanofibers for tissue engineering applications: a review.

Electrospun Poly(ε-caprolactone) Microfiber and Multilayer Nanofiber/Microfiber Scaffolds: Characterization of Scaffolds and Measurement of Cellular Infiltration

In vitro generated extracellular matrix and fluid shear stress synergistically enhance 3D osteoblastic differentiation

The development of bioresorbable composite polymeric implants with high mechanical strength.

The biocompatibility of rapidly degrading polymeric stents in porcine carotid arteries.