Electrospun Fibers for Spinal Cord Injury Research and Regeneration

Abstract

Electrospinning is the process by which a scaffold containing micrometer and nanometer diameter fibers are drawn from a polymer solution or melt using a large voltage gradient between a polymer emitting source and a grounded collector. Ramakrishna and colleagues first investigated electrospun fibers for neural applications in 2004. After this initial study, electrospun fibers are increasingly investigated for neural tissue engineering applications. Electrospun fibers robustly support axonal regeneration within in vivo rodent models of spinal cord injury. These findings suggest the possibility of their eventual use within patients. Indeed, both spinal cord and peripheral nervous system regeneration research over the last several years shows that physical guidance cues induce recovery of limb, respiration, or bladder control in rodent models. Electrospun fibers may be an alternative to the peripheral nerve graft (PNG), because PNG autografts injure the patient and are limited in supply, and allografts risk host rejection. In addition, electrospun fibers can be engineered easily to confront new therapeutic challenges. Fibers can be modified to release therapies locally or can be physically modified to direct neural stem cell differentiation. This review summarizes the major findings and trends in the last decade of research, with a particular focus on spinal cord injury. This review also demonstrates how electrospun fibers can be used to study the central nervous system in vitro.

Electrospun Fibers for Drug Delivery after Spinal Cord Injury and the Effects of Drug Incorporation on Fiber Properties

“…The sections presented subsequently are not meant to be comprehensive reviews but a general overview. For comprehensive reviews focusing on specific categories of biomaterials and providing a more thorough analysis of different biomaterial strategies under development for repair of the injured spinal cord refer to [Haggerty, and Oudega, 2013; Krishna et al, 2013; Macaya, and Spector, 2012; Pakulska et al, 2012; Perale et al, 2011; Schaub et al, 2015a; Straley et al, 2010; Tsintou et al, 2015]. The next sections present different biomaterial approaches either as being non-directional (unable to direct the extension of regenerating axons) or directional, and the results of such approaches when employed within an animal model of SCI.…”

“…Schaub et al recently reviewed the literature investigating the study of neural and glial cell response to electrospun fibers from in vitro studies and summarized the few studies employing electrospun fibers within animal models. Importantly, the review by Schaub and colleagues noted that general fibrous physical features (alignment, density, and diameter) influence the degree and extent of neurite outgrowth [Schaub et al, 2015a]. …”

Rapid fabrication of collagen bundles mimicking tumor-associated collagen signatures

“…Not only may the collagen bundles be applied to study cancer cell phenotypes and metastasis, but also provide new avenues for tissue engineering using a natural tissue component -collagen -as scaffolds. For example, aligned microscale bundled collagen may provide biocompatibility, adhesion, and proper topography for skeletal muscle growth 42,43 and nerve regeneration 44,45 .…”

Harnessing stem cells and biomaterials to promote neural repair

“…However, the bulkiness of these scaffold sheets makes them difficult to deliver in vivo and consequently more popular for use in vitro or for application in nerve repair. In the peripheral nervous system and spinal cord injury, the bandaging/wrapping potential of electrospun materials can be used to form a cylindrical nerve conduit (Schaub et al, 2016). Also, aligned fibres (formed using a rotating or oscillating collector during electrospinning) can provide directional guidance to cells.…”