New state of nanofibers in regenerative medicine

Figures & data

Table 1. Comparison of various nanofiber scaffold processing methods.

Scaffold processing method	General descriptions	General descriptions	Advantages	Disadvantages
Electrospinning	A process that essentially employs electrostatic forces for the production of polymer nanofibrous scaffolds, typically involves top-down approach.	Relatively easy, lab and industrial scales	Simple and cost-effective, capable to produce long and continuous fibers with control over fiber orientation, mechanical properties, size and shape, versatile to many polymers.	Using apparatus by high voltage
Self-assembly	A process in which atoms, molecules, and supramolecular aggregates organize and arrange themselves into an ordered structure through weak and noncovalent bonds; typically involves a bottom-up approach.	Difficult and lab scale	Mimic the biological process in certain circumstances	Complex process, limited to a few polymers, unable to produce long and continuous fibers with control over fiber orientation.
Phase separation	A process that involves various steps, typically raw material dissolution, gelation, solvent extraction, freezing and drying, leading to the formation of nanofibrous foam-like structure.	Easy and lab scale	Simple process, tailorable mechanical properties	Limited to a few polymers, longer processing time, unable to produce long and continuous fibers with control over fiber orientation.

Table 2. Example of nanofiber application in regenerative medicine.

Tissue	Nanofiber/scaffolds	Brief function	Cell or tissue	Reference(s)
Bone	Starch/PCL	Enhance cell attachment, organization and alkaline phosphatase (AP) activity	Human osteoblast cell line and rat bone marrow stromal cells	(Tuzlakoglu et al. 2005)
	PCL	Enhance ECM formation	Neonatal rat bone marrow-derived MSCs	(Yoshimoto et al. 2003)
	PCL/hyaluronn	Enhance ECM formation, better cell attachment	Neonatal rat bone marrow-derived MSCs	(Yang et al. 2006)
	Bioactive silk fibroin/bone morphogenetic protein-2 (BMP-2),	Higher calcium deposition, enhance transcription levels of bone-specific markers	Human bone marrow derived MSCs	(Li et al. 2006)
	Bioactive silk fibroin/hydroxyapatite	Improve bone formation	Human bone marrow derived MSCs	(Li et al. 2003)
	PCL/CaCO3	Good cell attachment and proliferation of human osteoblasts	Human osteoblasts	(Fujihara et al. 2005)
Cartilage	PLGA	Provide mechanical properties appropriate for cartilage tissue	Mouse fibroblast cells and bone marrow derived MSCs	(Li et al. 2002)
	Collagen type II	Adherence, propagation, and infiltration of the chondrocytes, the creation of pseudopodia	Human articular chondrocytes cell line	(Shields et al. 2004)
	PCL	Support chondrocyte proliferation, increase expression of cartilage specific ECM genes	Fetal bovine chondrocytes (FBCs), rat bone marrow stromal cells (rBMSC)	(Li et al. 2005)
Muscle	Poly(caprolactone-co-glycolide)-diol bonded to a diisocyanate, polyesterurethane linked with poly((R)-3-hydroxybutyric acid)-diol	Satisfactory mechanical properties and the absence of toxic residuals	Rat myoblast cell line (L6), murine myoblast cell line (C2C12) and primary human satellite cells (HSCs)	(Riboldi et al. 2005)
Ligament/Tendon	Polyurethane (PU)	Increase ECM production	Human ligament fibroblast (HLF)	(Lee et al. 2005)
	PLGA/knitted scaffold.	Increase of cell proliferation and cell function	Porcine bone marrow stromal cells	(Sahoo et al. 2006)
Blood vessels	Collagen-blended P(LLA-CL)	Enhance of cell viability, attachment, spreading and preserve human coronary artery endothelial cells (EC) markers	Human coronary artery endothelial cells (EC)	(He et al. 2005)
	Collagen-coated PCL fibers	Enhance cell attachment, migration, and proliferation, high quality morphology of actin filaments	Human coronary artery endothelial cells (HCAECs)	(He et al. 2005)
	Gelatin-grafted PCL nanofibers	Improve cell proliferation, maintain morphology of endothelial cells (EC)	Endothelial cells (ECs)	(Ma et al. 2005)
	Poly(L-lactide-co-caprolactone)	Increase in cell density, migration and proliferation	SMCs and ECs	(Mo et al. 2004)
	PLLA-CL	Enhance attachment and proliferation	Human coronary artery SMCs and ECs	(Xu et al. 2004)
	Poly(ester urethane)urea (PEUU)	Higher cellular density in perfusion cultures, No significant change in static cultures	Rat aortic SMCs	(Son et al. 2004)
	Composition of collagen type I, elastin and poly(d,l-lactide-coglycolide)	Improve physical properties	ECs and SMCs	(Stitzel et al. 2006)

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