Electrospun Scaffolds for Corneal Tissue Engineering: A Review

Abstract

Corneal diseases constitute the second leading cause of vision loss and affect more than 10 million people globally. As there is a severe shortage of fresh donated corneas and an unknown risk of immune rejection with traditional heterografts, it is very important and urgent to construct a corneal equivalent to replace pathologic corneal tissue. Corneal tissue engineering has emerged as a practical strategy to develop corneal tissue substitutes, and the design of a scaffold with mechanical properties and transparency similar to that of natural cornea is paramount for the regeneration of corneal tissues. Nanofibrous scaffolds produced by electrospinning have high surface area–to-volume ratios and porosity that simulate the structure of protein fibers in native extra cellular matrix (ECM). The versatilities of electrospinning of polymer components, fiber structures, and functionalization have made the fabrication of nanofibrous scaffolds with suitable mechanical strength, transparency and biological properties for corneal tissue engineering feasible. In this paper, we review the recent developments of electrospun scaffolds for engineering corneal tissues, mainly including electrospun materials (single and blended polymers), fiber structures (isotropic or anisotropic), functionalization (improved mechanical properties and transparency), applications (corneal cell survival, maintenance of phenotype and formation of corneal tissue) and future development perspectives.

Development and characterisation of electrospun timolol maleate-loaded polymeric contact lens coatings containing various permeation enhancers

“…The majority of the cornea is made up of the stroma; a collagen rich layer separated from the endothelium by Descemet's membrane. The Bowmen Layer connects the stroma to the epithelium, the outer most layer of the cornea (Kong and Mi 2016). The composition of these layers results in various degrees of hydrophilicity across the cornea and as a result of this, drug delivery through the cornea is a challenge.…”

“…EHDA is a versatile technique capable of producing a multitude of micro and nano sized structures for an array of application in the pharmaceutical arena (Mehta, et al 2017b). The one-step, easily modified process has been exploited in recent years with promising results in many remits including anti-cancer therapy (Kaplan, et al 2016;Lee, et al 2016), protein delivery (Hu, et al 2014;Ozcan, et al 2016;Rasekh, et al 2015;Zamani, et al 2014), transdermal delivery (Khan, et al 2014) and ocular drug delivery (Baskakova, et al 2016;Kong and Mi 2016;Mehta, et al 2015). The fundamental principle revolves around utilising an electrical field to atomise liquids to generate nano sized structures.…”

“…Modifying the process parameters (applied voltage and flow rate) alongside the physical properties of the liquid being atomised (viscosity, surface tension, electrical conductivity) allows the process to be optimised for specific criteria. Baskakova et al successfully developed drug-loaded polyvinylpyrrolidone (PVP) or polycaprolactone (PCL) fibers to act as potential intravitreal plants (Baskakova, et al 2016) whilst the electrospinning process has been used to produce fibrous scaffolds for corneal tissue engineering (Kong and Mi 2016). Mehta et al successfully utilised the EHD technique to develop double-sided functionalised nano-coatings for contact lenses (Mehta, et al 2015).…”

Mechanosensitive regulation of FGFR1 through the MRTF-SRF pathway

“…Among the different tissue engineering scaffolds, electrospun (ESP) scaffolds are being widely studied and are particularly interesting for defects of limited depth, but with a large surface area. Examples include cartilage repair [1] , skin patches [2] , corneal regeneration [3] , nerve guides [4] and vascular grafts [5] , among others. Electrospinning is a technique where synthetic or natural polymers are dissolved in volatile solvents and deposited onto a collector using a highly charged electric field.…”

Evaluation of collagen foam, poly(l‐lactic acid) nanofiber mesh, and decellularized matrices for corneal regeneration

“…20 Nanofibrous corneal constructs fabricated via electrospinning of both natural and synthetic polymers or their blends have been reported. 21 Because of their high porosity values and arrangeable fiber orientation, electrospun constructs have gained great attention as corneal biomimetic constructs. 22 Electrospinning enables to generate a tunable guidance platform to promote the specific corneal cell phenotype.…”