Corneal Tissue Engineering Research Articles

Biomimetic vs. Direct Approach to Deposit Hydroxyapatite on the Surface of Low Melting Point Polymers for Tissue Engineering.

Polymers are widely used in many applications in the field of biomedical engineering. Among eclectic selections of polymers, those with low melting temperature (Tm < 200 °C), such as poly(methyl methacrylate), poly(lactic-co-glycolic acid), or polyethylene, are often used in bone, dental, maxillofacial, and corneal tissue engineering as substrates or scaffolds. These polymers, however, are bioinert, have a lack of reactive surface functional groups, and have poor wettability, affecting their ability to promote cellular functions and biointegration with the surrounding tissue. Improving the biointegration can be achieved by depositing hydroxyapatite (HAp) on the polymeric substrates. Conventional thermal spray and vapor phase coating, including the Food and Drug Administration (FDA)-approved plasma spray technique, is not suitable for application on the low Tm polymers due to the high processing temperature, reaching more than 1000 °C. Two non-thermal HAp coating approaches have been described in the literature, namely, the biomimetic deposition and direct nanoparticle immobilization techniques. In the current review, we elaborate on the unique features of each technique, followed by discussing the advantages and disadvantages of each technique to help readers decide on which method is more suitable for their intended applications. Finally, the future perspectives of the non-thermal HAp coating are given in the conclusion.

Comparative behaviour of electrospun nanofibers fabricated from acid and alkaline hydrolysed gelatin: towards corneal tissue engineering

Gelatin is a hydrolysed form of collagen which is categorised as type A (acid hydrolysed) or type B (base hydrolysed), based on method of hydrolysis. In this work, we have studied the comparative properties of electrospun nanofibers of gelatin A (GA) and gelatin B (GB) prepared using a ternary solvent (glacial acetic acid/ethyl acetate/water). In addition, silk fibroin was used to improve the integrity and stability of gelatin nanofibrous sheets. Silk fibroin is known to serve as a potential implantable biomaterial because of its optimal mechanical stability, transparency, cell proliferation and tunable degradability. GA scaffold and silk permeated gelatin A nanofibrous scaffold (SFG) showed 50-70% of transparency comparable to that of adult rat and goat cornea. ATR-FTIR analysis showed the presence of native functional groups and bonds. Scanning electron microscope (SEM) micrographs revealed the porous nature of the scaffolds i.e., 48.08± 3.35 and 51.38 ± 3.72 for GA and GB, respectively. GB nanofibrous scaffolds got dissolved instantly in phosphate buffer solution (PBS), while GA scaffolds remained stable up to ∼ 11 h at 25˚C, however got degraded within 12 h when incubated at 37˚C. Furthermore, SFG scaffolds physically cross-linked with ethanol vapour displayed relatively improved stability when examined for at least 6 days at 37°C, minor weight loss when incubated in a lysozyme solution and facilitated the cellular proliferation significantly. Liquid retention capacity of the electrospun GA nanofibrous scaffolds was found to be nearly 800% from its original weight within 48 h. The electrospun nanofibrous scaffolds i.e., SFG facilitated ~72% of cellular proliferation compared to the control for SIRC [Statens Seruminstitut Rabbit Cornea] fibroblasts cells by 5th day of cell culture. Comparative outcomes reveal that the electrospun GA nanofibers possess significantly better integrity and noted stability in an aqueous environment compared to GB nanofibrous scaffold. Moreover, owing to the enhanced integrity and better stability the GA nanofibrous scaffold in combination with silk fibroin could be exploited in corneal tissue engineering applications where transparency plays an indispensable characteristic.

Isolation and enrichment of melanocytes from human corneal limbus using CD117 (c-Kit) as selection marker

Limbal melanocytes (LM) are located in the basal epithelial layer of the corneoscleral limbus and interact with adjacent limbal epithelial progenitor cells. The exploration of their biological role in the maintenance of the limbal stem cell niche has been limited by the difficulty of LM isolation and cultivation. Here, we report on a facile protocol for the efficient isolation and enrichment of pure populations of human LMs by fluorescence-activated cell sorting (FACS) using antibodies raised against the cell surface marker CD117 (c-Kit). The enriched LMs retain self-renewal capacity and sustained melanin production, and are suitable to study the potential of LMs in stem cell-based corneal tissue engineering.

Corneal endothelium tissue engineering: An evolution of signaling molecules, cells, and scaffolds toward 3D bioprinting and cell sheets.

Cornea is an avascular and transparent tissue that focuses light on retina. Cornea is supported by the corneal-endothelial layer through regulation of hydration homeostasis. Restoring vision in patients afflicted with corneal endothelium dysfunction-mediated blindness most often requires corneal transplantation (CT), which faces considerable constrictions due to donor limitations. An emerging alternative to CT is corneal endothelium tissue engineering (CETE), which involves utilizing scaffold-based methods and scaffold-free strategies. The innovative scaffold-free method is cell sheet engineering, which typically generates cell layers surrounded by an intact extracellular matrix, exhibiting tunable release from the stimuli-responsive surface. In some studies, scaffold-based or scaffold-free technologies have been reported to achieve promising outcomes. However, yet some issues exist in translating CETE from bench to clinical practice. In this review, we compare different corneal endothelium regeneration methods and elaborate on the application of multiple cell types (stem cells, corneal endothelial cells, and endothelial precursors), signaling molecules (growth factors, cytokines, chemical compounds, and small RNAs), and natural and synthetic scaffolds for CETE. Furthermore, we discuss the importance of three-dimensional bioprinting strategies and simulation of Descemet's membrane by biomimetic topography. Finally, we dissected the recent advances, applications, and prospects of cell sheet engineering for CETE.

Corneal epithelium tissue engineering: recent advances in regeneration and replacement of corneal surface.

Currently, many corneal diseases are treated by corneal transplantation, artificial corneal implantation or, in severe cases, keratoprosthesis. Owing to the shortage of cornea donors and the risks involved withartificial corneal implants, such as infection transmission, researchers continually seek new approaches for corneal regeneration. Corneal tissue engineering is a promising approach that has attracted much attention from researchers and is focused on regenerative strategies using various biomaterials in combination with different cell types. These constructs should have the ability to mimic the native tissue microenvironment and present suitable optical, mechanical and biological properties. In this article, we review studies that have focused on the current clinical techniques for corneal replacement. We alsodescribe tissue-engineering and cell-based approaches for corneal regeneration.

Regulation of Keratocyte Phenotype and Cell Behavior by Substrate Stiffness.

Corneal tissue engineering is an alternative way to solve the problem of lack of corneal donor tissue in corneal transplantation. Keratocytes with a normal phenotype and function in tissue-engineered cornea would be critical for corneal regeneration. Although the role of extracellular/substrate material stiffness is well-known for the regulation of the cell phenotype and cell behavior in many different cell types, its effects in keratocyte culture have not yet been thoroughly studied. This project studied the effect of substrate stiffness on the keratocyte phenotype marker expression and typical cell behavior (cell adhesion, proliferation, and migration), and the possible mechanisms involved. Human primary keratocytes were cultured on tissue culture plastic (TCP, ∼106 kPa) or on plates with the stiffness equivalent of physiological human corneal stroma (25 kPa) or vitreous body (1 kPa). The expression of keratocyte phenotype markers, cell adhesion, proliferation, and migration were compared. The results showed that the stiffness of the substrate material regulates the phenotype marker expression and cell behavior of cultured keratocytes. Physiological corneal stiffness (25 kPa) superiorly preserved the cell phenotype when compared to the TCP and 1 kPa group. Keratocytes had a larger cell area when cultured on 25 kPa plates as compared to on TCP. Treatment of cells with NSC 23766 (Rac1 inhibitor) mimicked the response in the cell phenotype and behavior seen in the transition from soft materials to stiff materials, including the cytoskeletal structure, expression of keratocyte phenotype markers, and cell behavior. In conclusion, this study shows that substrate stiffness regulates the cell phenotype marker expression and cell behavior of keratocytes by Rac1-mediated cytoskeletal reorganization. This knowledge contributes to the development of corneal tissue engineering.

Prospects and Challenges of Translational Corneal Bioprinting.

Corneal transplantation remains the ultimate treatment option for advanced stromal and endothelial disorders. Corneal tissue engineering has gained increasing interest in recent years, as it can bypass many complications of conventional corneal transplantation. The human cornea is an ideal organ for tissue engineering, as it is avascular and immune-privileged. Mimicking the complex mechanical properties, the surface curvature, and stromal cytoarchitecure of the in vivo corneal tissue remains a great challenge for tissue engineering approaches. For this reason, automated biofabrication strategies, such as bioprinting, may offer additional spatial control during the manufacturing process to generate full-thickness cell-laden 3D corneal constructs. In this review, we discuss recent advances in bioprinting and biomaterials used for in vitro and ex vivo corneal tissue engineering, corneal cell-biomaterial interactions after bioprinting, and future directions of corneal bioprinting aiming at engineering a full-thickness human cornea in the lab.

Epithelial basement membrane of human decellularized cornea as a suitable substrate for differentiation of embryonic stem cells into corneal epithelial-like cells.

The ability to decellularize and recellularize the corneas deemed unsuitable for transplantation may increase the number of available grafts. Decellularized corneas (DCs) may provide a natural microenvironment for cell adhesion and differentiation. Despite this, no study to date has evaluated their efficacy as a substrate for the induction of stem cell differentiation into corneal cells. The present study aimed to compare the efficiency of NaCl and NaCl plus nucleases methods to decellularize whole human corneas, and to investigate the effect of epithelial basement membrane (EBM) of whole DCs on the ability of human embryonic stem cells (hESCs) to differentiate into corneal epithelial-like cells when cultured in animal serum-free differentiation medium. As laminin is the major component of EBM, we also investigated its effect on hESCs differentiation. The decellularization efficiency and integrity of the extracellular matrix (ECM) obtained were investigated by histology, electron microscopy, DNA quantification, immunofluorescence, and nuclear staining. The ability of hESCs to differentiate into corneal epithelial-like cells when seeded on the EBM of DCs or laminin-coated wells was evaluated by immunofluorescence and RT-qPCR analyses. NaCl treatment alone, without nucleases, was insufficient to remove cellular components, while NaCl plus nucleases treatment resulted in efficient decellularization and preservation of the ECM. Unlike cells induced to differentiate on laminin, hESCs differentiated on DCs expressed high levels of corneal epithelial-specific markers, keratin 3 and keratin 12. It was demonstrated for the first time that the decellularized matrices had a positive effect on the differentiation of hESCs towards corneal epithelial-like cells. Such a strategy supports the potential applications of human DCs and hESCs in corneal epithelium tissue engineering.

Corneal stromal regeneration by hybrid oriented poly (ε-caprolactone)/lyophilized silk fibroin electrospun scaffold

Applying biological macromolecule like silk fibroin (SF) is a promising material for corneal tissue engineering. However, designing an appropriate tissue-like construct to compensate the shortages of traditional routes are still challenging. SF besides possessing biocompatibility and transparency, the biomaterial should be mechanically strong. In the present study, a hybrid scaffold composed of poly-ε-caprolactone (PCL)-silk fibroin (SF) is fabricated through electro spinning technique. The aligned and non-aligned PCL-SF scaffolds with various weight ratios are fabricated. The results reveal that the addition of SF yields the scaffolds with more uniform and aligned structure. The ultimate tensile strength and Young's modulus of aligned and non-aligned PCL-SF (60:40 and 50:50) fibers are in an acceptable range for cornea applications. It is noteworthy that the aligned PCL-SF (60:40 and 50:50) scaffolds have more transparency, hydrophilicity, water uptake, and in vitro degradation rate than the other scaffolds. The cell compatibility results show that human stromal keratocyte cells are attached and proliferated on the aligned and non-aligned PCL-SF scaffolds. The overall results recommend that PCL-SF (60:40 and 50:50) scaffolds have a great potential for human corneal stromal regeneration.

Preparation of collagen/cellulose nanocrystals composite films and their potential applications in corneal repair.

As the main component of the natural cornea, collagen (COL) has been widely applied to the construction of corneal repair materials. However, the applications of collagen are limited due to its poor mechanical properties. Cellulose nanocrystals (CNCs) possess excellent mechanical properties, optical transparency and good biocompatibility. Therefore, in this study, we attempted to introduce cellulose nanocrystals into collagen-based films to obtain corneal repair materials with a high strength. CNCs were incorporated at 1, 3, 5, 7 and 10 wt%. The physical properties of these composite films were characterized, and in vitro cell-based analyses were also performed. The COL/CNC films possessed better mechanic properties, and the introduction of CNCs did not affect the water content and light transmittance. The COL/CNC films demonstrated good biocompatibility toward rabbit corneal epithelial cells and keratocytes in vitro. Moreover, the collagen films with appropriate ration of CNCs effectively induced the migration of corneal epithelial cells and inhibited the myofibroblast differentiation of keratocytes. A collagen film with 7 wt% CNCs displayed the best combination of physical properties and biological performance in vitro among all the films. This study describes a nonchemical cross-linking method to enhance the mechanical properties of collagen for use in corneal repair materials and highlights potential application in corneal tissue engineering.

An experimental study on the construction of tissue engineering corneal stromal stent with Smile derived corneal stromal lens

An experimental study on the construction of tissue engineering corneal stromal stent with Smile derived corneal stromal lens

Development of an Anti-Inflammatory Drug-Incorporated Biomimetic Scaffold for Corneal Tissue Engineering

Purpose: The aim of this study was to design naproxen sodium (NS)-containing, biomimetic, porous poly(lactide-co-glycolide) (PLGA) scaffolds for regeneration of damaged corneal epithelium. Methods: NS-incorporated PLGA scaffolds were prepared using the emulsion freeze-drying method and then coated with collagen or poly-l-lysine. Porosity measurements of the scaffolds were performed by the gas adsorption/desorption method and the scaffolds demonstrated highly porous, open-cellular pore structures with pore sizes from 150 to 200 μm. Results: The drug loading efficiency of scaffolds was found to be higher than 84%, and about 90%-98% of NS was released at the end of 7 days with a fast drug release rate at the initial period of time and then in a slow and sustained manner. The corneal epithelial cells were isolated from New Zealand white rabbits. The obtained cells were seeded onto scaffolds and continued to increase during the time period of the study, indicating that the scaffolds might promote corneal epithelial cell proliferation without causing toxic effects for at least 10 days. Conclusions: The NS-loaded PLGA scaffolds exhibited a combination of controlled drug release and biomimetic properties that might be attractive for use in treatment of corneal damage both for controlled release and biomedical applications.

Active loading graphite/hydroxyapatite into the stable hydroxyethyl cellulose scaffold nanofibers for artificial cornea application

The design of biocompatible porous scaffolds that encourage cell adhesion for corneal tissue engineering applications continues to be challenging. In addition to porous hydrogels, nanofibers that can simulate the extracellular matrix structure for cell adhesion would be beneficial. Graphite and nano-hydroxyapatite (nHA) are two bioactive materials that have been used to improve cell adhesion in scaffolds for corneal tissue engineering. In this study, nanofibers were fabricated from hydroxyethyl cellulose and polyvinyl alcohol (PVA) and cross-linked by glutaraldehyde bound to graphite and nano-hydroxyapatite. This scaffold surrounded a transparent hydrogel core from PVA that was cross-linked by freeze-thawing cycles. The chemical and mechanical evaluations demonstrated that nanofibers met the requirements as a scaffold for corneal tissue engineering. The results showed that when the concentration of nHA was approximately 1.66 wt%, the morphology of human epithelial cells did not change, and clot formation occurred around the scaffold during the 1-week in vivo implantation.

Epigallocatechin gallate loaded electrospun silk fibroin scaffold with anti-angiogenic properties for corneal tissue engineering

Avascularity is the first requirement for corneal tissue engineering. The goal of this study was to develop an epigallocatechin gallate (EGCG)-loaded silk fibroin-based scaffold with anti-angiogenesis properties for corneal tissue engineering. Silk nanofibers were prepared by electrospinning, and treated with methanol to enhance water insolubility. Scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, tensile testing, differential scanning calorimetry, contact angle testing, and porosimetry were used to characterize the scaffold. The suitability of the scaffold as support for limbal cells was demonstrated by scanning electron microscopy. In situ drug loading of EGCG into the scaffold successfully produced a homogeneous structure of nanofibers and the loaded nanofibers released the drug over 144 h in a controlled-manner. The appropriate dose of the anti-angiogenic compound to be loaded in the electrospun nanofibers was determined by MTT assay and using human umbilical vein endothelial cells (HUVEC). The findings showed a dose-dependent inhibition of cell proliferation with the IC50 values of 43.06 ± 2.51 μM and 47.1 ± 3.46 μM after 24 and 72 h treatment, respectively. The MTT results also revealed that the prepared fibrous scaffolds containing EGCG promoted the inhibition of HUVEC during in vitro incubation. It is anticipated that the EGCG-loaded scaffold has the potential for use as a delivery system for corneal tissue engineering.

The Self-assembly Approach as a Tool for the Tissue Engineering of a Bi-lamellar Human Cornea.

Tissue engineering is a flourishing field of regenerative medicine that allows the reconstruction of various tissues of our body, including the cornea. In addition to addressing the growing need for organ transplants, such tissue-engineered substitutes may also serve as good in vitro models for fundamental and preclinical studies. Recent progress in the field of corneal tissue engineering has led to the development of new technologies allowing the reconstruction of a human bi-lamellar cornea. One unique feature of this model is the complete absence of exogenous material. Indeed, these human corneal equivalents are exclusively composed of untransformed human corneal fibroblasts (hCFs) entangled in their own extracellular matrix, as well as untransformed human corneal epithelial cells (hCECs), both of which isolated from donor corneas. The reconstructed human bi-lamellar cornea thereby exhibits a well-organized stroma as well as a well-differentiated epithelium. This chapter describes the methods used for the isolation and culture of hCFs, the production and assembly of hCFs stromal sheets, the seeding of hCECs, and the maturation of the tissue-engineered cornea.

Decellularized Human Stromal Lenticules Combine with Corneal Epithelial-Like Cells: A New Resource for Corneal Tissue Engineering.

The lack of donor corneal tissue or the immunological rejection remains a challenge for individuals with limbal stem cell deficiency (LSCD) who are treated with keratoplasty. Numerous lenticules which were extracted by small incision lenticule extraction (SMILE) appear to be useful materials for keratoplasty. In order to reduce the incidence of allograft rejection, lenticules would be decellularized. Lenticules which were treated with liquid nitrogen and nucleases had no cellular and nuclear materials remained. Human induced pluripotent stem cells (iPSCs) can be generated from the patient who requires keratoplasty, offering an autologous alternative and eliminating the risk of graft rejection. We found that BMP-4, RA, N-2 supplement, hEGF, B27, decellularized human stromal lenticules, conditioned medium, or induction medium promoted the differentiation of human iPSCs with high purity. The results showed that human iPSCs cultured for 4 days in differentiation medium A, 14 days in condition medium, and 1 week in induction medium on decellularized human stromal lenticules developed markedly higher expression of the markers P63, CK3, and CK12 than did those in the other methods. The level of gene expression of the epithelial and pluripotency markers and analysis by scanning electron microscopy and immunohistochemistry also showed successful differentiation. After inducing differentiation in vitro, corneal epithelial-like cells were induced. In the study, we investigated the possibility of a new resource for corneal tissue engineering.

Development and Characterization of an Acellular Porcine Small Intestine Submucosa Scaffold for Use in Corneal Epithelium Tissue Engineering

ABSTRACTPurpose: To produce an acellular small intestine submucosa (SIS) that would be a suitable scaffold for corneal epithelium tissue engineering.Methods: The SIS was decellularized by immersion in 0.1% (wt/vol) sodium dodecyl sulfate (SDS). The efficacy of acellularization was confirmed by histological observation and DNA quantification. The mechanical properties were evaluated by uniaxial tensile testing. ELISA was performed to assess the growth factor contents. The cytotoxicity of SIS scaffolds and extracts to rabbit corneal epithelial cells was determined by CCK-8 assay. We also investigated the inflammatory reaction of SIS implanted subcutaneously in a rat. The biocompatibility was studied by rabbit interlamellar corneal transplantation and reseeding assay with cornea-derived cells. Immunofluorescent staining was used to detect the expression of CK3, ZO-1 and K13.Results: Histological analyses showed that complete cell removal was achieved, and the DNA quantity, which reflects the presence of cellular materials, was significantly diminished in acellular SIS. Collagen fibers were properly preserved and appeared in an orderly fashion. The tissue structure, the mechanical properties and the growth factor contents within the acellular SIS were well retained. The CCK8 assay demonstrated that the acellular SIS scaffolds and extracts had no cytotoxicity to rabbit corneal epithelial cells. There was no sign that an immune reaction occurred with acellular SIS implanted subcutaneously in a rat. In fact, in vivo implantation to rabbit interlamellar stromal pockets showed good biocompatibility. We also observed that clusters of rabbit corneal epithelial cells were growing well on the surface of the SIS in vitro and the distinctive CK3, ZO-1 for corneal epithelial cells was detected.Conclusions: The decellularized SIS retained the major structural components. The matrix is biocompatible with cornea-derived cells and might be a suitable scaffold for corneal epithelium tissue engineering.

Genipin-crosslinked polyvinyl alcohol/silk fibroin/nano-hydroxyapatite hydrogel for fabrication of artificial cornea scaffolds—a novel approach to corneal tissue engineering

Design of artificial corneal scaffolds substitute is crucial for replacement of impaired cornea. In this paper, porous polyvinyl alcohol/silk fibroin/nano-hydroxyapatite (PVA/SF/n-HA) composite hydrogel was prepared via the genipin (GP) cross-linking, the pore diameter of the hydrogel ranged from 8.138 nm and 90.269 nm, and the physical and physiological function of hydrogel were investigated. The resulting hydrogel exhibited favourable physical properties. With the GP content increasing, the structural regularity of PVA/SF/n-HA composite hydrogel was enhanced and the thermal stability was improved. The moisture content was slightly decreased and generally maintained at approximately 70%. The tensile strength was heightened up to 0.64 MPa, while the breaking elongation was decreased slightly. Moreover, the biofunction was investigated. The in vitro degradation test demonstrated that with the addition of GP, the stability of the composite hydrogels in protease XIV solution was promoted and the three-dimensional porosity structure of composite hydrogels was maintained as ever. And the human corneal fibroblasts (HCFs) were employed to examine the cells cytotoxicity of the PVA/SF/n-HA composite hydrogels with different GP content by CCK-8 assay. Based on confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM), HCFs had individually commendable adhesion and proliferation on PVA/n-HA/SF composite hydrogel. HCFs proliferated and grew into the pores of composite hydrogel. The results of biocompatibility experiments of composite hydrogel suggested that it was no acute toxicity, in vitro cytotoxicity was 0 or 1 grade. Overall, results from this paper, PVA/n-HA/SF composite hydrogel was a qualified medical material which conformed to the national standard, could be a promising alternative for artificial cornea scaffold material—a novel approach to corneal tissue engineering.

Design and characterization of biodegradable multi layered electrospun nanofibers for corneal tissue engineering applications.

Tissue engineering is one of the most promising areas for treatment of various ophthalmic diseases particularly for patients who suffer from limbal stem cell deficiency and this is due to the lack of existence of appropriate matrix for stem cell regeneration. The aim of this research project is to design and fabricate triple layered electrospun nanofibers as a suitable corneal tissue engineering scaffold and the objective is to investigate and perform various in vitro tests to find the most optimum and suitable scaffold for this purpose. Electrospun scaffolds were prepared in three layers. Poly(d, l-lactide-co-glycolide; PLGA, 50:50) nanofibers were electrospun as outer and inner layers of the scaffold and aligned type I collagen nanofibers were electrospun in the middle layer. Furthermore, the scaffolds were cross-linked by 1-ethyl-3-(3 dimethylaminopropyl) carbodiimide hydrochloride and glutaraldehyde. Structural, physical, and mechanical properties of scaffolds were investigated by using N2 adsorption/desorption isotherms, Fourier transform infrared spectroscopy, contact angle measurement, tensile test, degradation, shrinkage analysis, and scanning electron microscopy (SEM). In addition, capability to support cell attachment and viability were characterized by SEM, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay, and 4',6-diamidino-2-phenylindole staining. According to the result of Brunauer-Emmett-Teller analysis, specific surface area of electrospun scaffold was about 23.7 m2 g-1 . Tensile tests on cross-linked scaffolds represented more suitable hydrophilicity and tensile behavior. In addition, degradation rate analysis indicated that noncross-linked scaffolds degraded faster than cross-linked one and cross-linking led to controlled shrinkage in the scaffold. The SEM analysis depicted nano-sized fibers in good shape. Also, the in vitro study represented an improved cell attachment and proliferation in the presence of human endometrial stem cells for both cross-linked and noncross-linked samples. The current study suggests the possibility of producing an appropriate substrate for successful cornea tissue engineering with a novel design.

Tobramycin Collagen Fast Dissolving Ocular Films for Corneal Tissue Engineering of Keratoconus

Fast dissolving films are a one of novel dosage form in pharmaceutical research. They have convenience and ease of use over other dosage forms such as orally disintegrating tablets and immediate release tablets. In the present research, rapidly dissolving films of Tobramycin were developed using Polyvinyl acetate (PVA) and polyvinyl pyrollidone (PVP) as film forming polymers by solvent casting method. The prepared films were evaluated for drug content, weight variation, thickness and in vitro in vivo disintegration time. The in vitroand in vivodissolving time of the optimized formulation was found to be below 15–40 seconds respectively. The prepared films exhibited good integrity and thickness. In vitro dissolution studies were performed as per the FDA dissolution guidelines for about 3 minutes, the optimum formulation released complete drug within 3 minutes. Statistical analysis showed no drug polymer interaction.