Oriented nanofibrous silk as a natural scaffold for ocular epithelial regeneration

Abstract

The aim of this study was to develop nanofibrous silk substrates for limbal stem cell expansion that can serve as a potential alternative substrate to replace human amniotic membrane. The human limbal stem cell was used to evaluate the biocompatibility of substrates (random and oriented nanofibrous mats, and human amniotic membrane) based on their phenotypic profile, viability, proliferation, and attachment ability. Biocompatibility results indicated that all substrates were highly biocompatible, as limbal stem cells could favorably attach and proliferate on the nanofibrous surfaces. Microscopic figures showed that the human limbal stem cells were firmly anchored to the substrates and were able to retain a normal corneal stem cell phenotype. Microscopic analyses illustrated that cells infiltrated the nanofibers and successfully formed a three-dimensional corneal epithelium, which was viable for 15 days. Immunocytochemistry and real-time PCR results revealed no change in the expression profile of limbal stem cells grown on nanofibrous substrates when compared to those grown on human amniotic membrane. In addition, electrospun nanofibrous silk substrates especially oriented mat provides not only a milieu supporting limbal stem cells expansion, but also serve as a useful alternative carrier for ocular surface tissue engineering and could be used as an alternative substrate to amniotic membrane.

Electrospun Scaffolds for Corneal Tissue Engineering: A Review

“…An silk electrospun mat (Figure 1B), which was highly compatible, was produced to serve as a potential alternative substrate to HAM. Human limbal stem cells could favorably attach and proliferate on the nanofibrous surface, and cells were able to infiltrate the nanofibers and successfully form a 3D corneal epithelium [51]. …”

“…Much research work has been performed to study how to maintain the phenotype of corneal cells, such as limbus stem cells, corneal epithelial cells and keratocytes. Limbus stem cells were demonstrated to retain a normal corneal stem cell phenotype on the electrospun silk scaffolds [51], PCL scaffolds [44,82] and blended PHBV/gelatin scaffolds [42]. The potentials of electrospun scaffolds made of polyhydroxybutyrate (PHB), PHBV, and PCL were studied to serve as drug-screening platforms for corneal keratocyte tissues by Pedram Azari et al They cultured keratocytes on these scaffolds, and the result showed that cells had a high viability and proliferation and that PCL exhibited good potential for maintaining the cell phenotype with high expressions of LUM, ALDH, VIM, COL.1, and a-SMA2 [45].…”

“…Alireza Baradaran-Rafii utilized electrospun a PHBV/gelatin scaffold to culture limbus epithelial cells, and the corneal epithelium also formed [42]. The electrospun silk scaffold and PLGA nanofibrous scaffold were also demonstrated to be suitable substitutes for promoting epithelial cells to form epithelium [47,51]. Jian Wu et al electrospun an aligned PEUU mat inoculated with hCSSCs, and they found that the PEUU substrate could induce the alignment of hCSSCs, which elaborated a dense collagenous matrix, 8–10 um in thickness, deposited on the PEUU substratum.…”

“…Reproduced from [48], with permission from © 2014 Tylor and Francis; ( B ) Oriented nanofibers of silk scaffold. Reproduced from [51], with permission from © 2015 Tylor and Francis; ( C ) Randomly oriented PCL scaffold. Reproduced from [44], with permission from © 2014 The Association for Research in Vision and Ophthalmology; ( D ) A section of the electrospun scaffold showing a horseshoe electrospun micro-pocket.…”

Application of polymeric nanofibers in soft tissues regeneration

“…Nanotechnology refers to one of the rapidly growing scientific disciplines studying and developing objects and materials with characteristic dimensions to resolve many of the diseases and also use in medical sciences such diagnostic and treatment designs. The most common nanostructures are dendrimers, fullerenes, hydrogels, aerogels, nano composites, nanowires, quantum dots, nanocages, nanoparticles, nanorods, nanoshells and nanofibres . Nanofibers show suitable properties such as porosity, structurally similar to the extracellular matrix (ECM), good cell adhesion and physical & mechanical properties; therefore they can be used for tissue regeneration, wound dressing, drug delivery and medical prostheses.…”