Engineering of Corneal Tissue through an Aligned PVA/Collagen Composite Nanofibrous Electrospun Scaffold

Abstract

Corneal diseases are the main reason of vision loss globally. Constructing a corneal equivalent which has a similar strength and transparency with the native cornea, seems to be a feasible way to solve the shortage of donated cornea. Electrospun collagen scaffolds are often fabricated and used as a tissue-engineered cornea, but the main drawback of poor mechanical properties make it unable to meet the requirement for surgery suture, which limits its clinical applications to a large extent. Aligned polyvinyl acetate (PVA)/collagen (PVA-COL) scaffolds were electrospun by mixing collagen and PVA to reinforce the mechanical strength of the collagen electrospun scaffold. Human keratocytes (HKs) and human corneal epithelial cells (HCECs) inoculated on aligned and random PVA-COL electrospun scaffolds adhered and proliferated well, and the aligned nanofibers induced orderly HK growth, indicating that the designed PVA-COL composite nanofibrous electrospun scaffold is suitable for application in tissue-engineered cornea.

Poly(Vinyl Alcohol)-Based Nanofibrous Electrospun Scaffolds for Tissue Engineering Applications

“…As a synthetic polymer, PVA has been widely used as a supporting material for corneal TE due to its transparency, flexibility and mechanical stability [23,94]. Natural polymers are not as frequent since this combination of properties is difficult to attain.…”

“…The clear and transparent nature of PVA has also attracted attention to produce bioengineered corneal equivalents. A healthy cornea contributes to two-thirds of the total refractive power of the eye; as such, a corneal equivalent should be able to transmit most of the visible light without compromising its mechanical integrity [23]. This polymer's ability to be processed with various degrees of hydrolysis, a property intimately related with its degradation rate, has also raised PVA's profile when it comes to drug delivery systems.…”

Fiber reinforced GelMA hydrogel to induce the regeneration of corneal stroma

“…Penetrating keratoplasty is the most commonly used grafting procedure to improve visual impairment from severe corneal diseases due to the high short-term success; however, the availability of donor corneal tissue cannot meet the global requirements 3 . Artificial keratoprostheses, animal decellularized corneal tissue (e.g., porcine cornea), and human amniotic membrane have also been used for the treatment of corneal disorders because of the shortage of donor cornea; however, these methods do not have high success ratios or approved use in tissue transplantation, despite that some methods are in current clinical practice 4 . For the reason above, it is essential and urgent to develop therapeutic alternatives to corneal transplantation, including cell-based therapy and bioengineered constructs.…”

“…Various bioengineering approaches have been attempted to fabricate corneal equivalence based on natural (e.g., collagen 1,4,5 , gelatin 6 , chitosan 7 , silk 8 , etc) or synthetic (e.g., poly (ethylene glycol) (PEG) 9 , poly (ε-caprolactone) (PCL) 10 , poly(lactic-co-glycolic acid) (PLGA) 1,11 , poly-hydroxyethylmethacrylate (PHEMA) 12 , etc) materials or the combination of natural and synthetic materials 1,4,13 by using the techniques of casting 14 , hydrogel 15 , 3D printing 16 , electrospinning 17,18 , and the combination of two or more of these processes 17 . Although these therapies and constructs have demonstrated acceptable mechanical properties and optical transmittance and can support corneal cells adhesion, migration, proliferation, and differentiation well, they fail to mimic the natural microenvironment of the native complex corneal tissue, and the most complicated part among the corneal tissue is the stroma.…”

Desenvolvimento de membranas de PVA/Colágeno aniônico como novos sistemas poliméricos de liberação controlada de antibióticos

“…Portanto, as blendas de PVA/colágeno apresentam certo grau de compatibilidade devido à hidrofilicidade de ambos polímeros e à boa capacidade para a formação de filmes (PENG et al, 2012). As propriedades mecânicas e a transparência do PVA, juntas com a afinidade celular do colágeno têm sido aproveitadas para o desenvolvimento de ceratopróteses com características fisiológicas e morfológicas similares às da córnea (MIYASHITA et al, 2006;WU et al, 2018…”