Nanofibrous composites for tissue engineering applications

Abstract

Development of artificial matrices for tissue engineering is a crucial area of research in the field of regenerative medicine. Successful tissue scaffolds, in analogy with the natural mammalian extracellular matrix (ECM), are multi-component, fibrous, and on the nanoscale. In addition, to this key morphology, artificial scaffolds must have mechanical, chemical, surface, and electrical properties that match the ECM or basement membrane of the specific tissue desired. In particular, these material properties may vary significantly for the four primary tissues in the body: nerve, muscle, epithelial, and connective. In order to address this complex array of attributes with a polymeric material, a nanocomposite approach, employing a blend of materials, addition of a particle to enhance particular properties, or a surface treatment, is likely to be required. In this review, we examine nanocomposite approaches to address these diverse needs as a function of tissue type. The review is intended as a bridge between material scientists and biomedical researchers to give basic background information on tissue biology to the former, and on material processing approaches to the latter, in a general manner, and specifically review fibrous nanocomposite materials that have previously been used for cell studies, either in vivo or in vitro .

The extracellular matrix at a glance

“…Electrospun biomaterial (silk, lactic acid and glycolic acid polymers) (Zhang et al, 2009;McCullen et al, 2009) ↓ Mechanical stability, tensile strength, elasticity …”

“…In this respect, synthetic matrices have been developed that feature defined and tunable compositions, organization, mechanics and ECM remodeling capabilities. Indeed, in response to this need there has been literally an explosion of publications describing the generation and application of synthetic ECMs for tissue regeneration, and the reader is referred to some excellent reviews on these topics (Ayres et al, 2009;Dutta and Dutta, 2009;Lutolf and Hubbell, 2005;McCullen et al, 2009;Rosso et al, 2005;Zisch et al, 2003). One example is given by polyethylene glycol (PEG) hydrogels -frequently used biologically compatible synthetic matrices that support cell adhesion, viability and growth (Lutolf and Hubbell, 2005).…”

“…These peptides-amphiphiles are amenable to modification by covalent binding of native proteins and MMP-degradable ECM peptides. Alternatively, poly(lactic-co-glycolic acid) (PLGA), a copolymer of glycolic acid and lactic acid (McCullen et al, 2009) that is inherently biodegradable as it is hydrolyzed into lactic acid and glycolic acid, has been developed and can be readily conjugated to various ECM ligands and peptides, or coated with collagen or chitosan to support cell adhesion, viability and growth. Indeed, one of the most exciting recent advances in the field has been the development of modular biocompatible ECMs, which contain ligand-binding cassettes and have tunable stiffness features that permit a precise patterning of cell adhesion in 2D and 3D formats (Serban and Prestwich, 2008).…”

Multifunctional Nanofibers towards Active Biomedical Therapeutics

“…ECM is composed of several fibrous macromolecules with a length/thickness ratio greater than 100. The diameter of these macromolecules is about 500 nm [49]. Thus electrospun nanofibers can be used to prepare similar-sized scaffolds.…”

Scarless Wound Healing

“…24 Tissue engineering products are constructed from a variety of materials (eg, polymers, ceramics, and metals) for the purpose of mimicking the ECM to improve wound healing, but these products can elicit unwanted inflammatory or immune responses that lead to fibrogenic development. 25,26 With the expected impairment that results from scarring, researchers have examined using anti-inflammatory therapies or anti-TGF-b medications as preventive measures to deter fibrosis formation. It has been found that scarring effects from TGF-b1 secretion can be prevented in injured tissues through multiple methods, including blocking the actual TGF-b ligand; blocking the TGF-b receptors, which interferes with downstream signaling; or selectively inhibiting coactivators of TGF-b that lead to scar tissue formation.…”