Polycaprolactone Nanofibrous Scaffolds Research Articles

Sputtered zirconium based metallic glassy thin films onto electrospun PCL nanofibrous scaffolds for enriching bioactivity

Surface modification of electrospun Polycaprolactone (PCL) nanoscaffold is to enhance surface properties, particularly bioactivity. In this paper, electrospinning was employed to produce PCL nanoscaffolds and enhancing the bioactivity of the electrospun PCL scaffolds by sputtering of Zirconium based thin film metallic glasses (Zr -TFMGs). The Energy Dispersive Spectroscopy (EDS) analysis exhibited the presence of Zr, Ti and Si and surface topography by Atomic Force Microscopy (AFM) revealed the smooth surface of metallic glasses with nanofibrous structures. The sputtered samples were subjected to immersion test in Simulated Body Fluid (SBF) to analyze the apatite forming ability of Zr–Ti–Si metallic glasses. After 21days of incubation, SEM clearly showed the spherical structures of apatite formed on the surface of modified electrospun PCL. Cell viability studies using L929 fibroblast cells indicates the higher proliferation rate for the Zr based TFMG sputtered PCL scaffold specimen than the uncoated neat PCL scaffold and indicating the bioactive nature of Zr based TFMG. Contact angle of TFMG sputtered sample exhibited the hydrophobic surface which is helpful in preventing the biomedical devices from blood coagulation.

Design and fabrication of dual-layer PCL nanofibrous scaffolds with inductive influence on vascular cell responses

Confronted with the profound threat of cardiovascular diseases to health, vascular tissue engineering presents potential beyond the limitations of autologous and allogeneic grafts, offering a promising solution. This study undertakes an initial exploration into the impact of a natural active protein, elastin, on vascular cell behavior, by incorporating with polycaprolactone to prepare fibrous tissue engineering scaffold. The results reveal that elastin serves to foster endothelial cell adhesion and proliferation, suppress smooth muscle cell proliferation, and induce macrophage polarization. Furthermore, the incorporation of elastin contributes to heightened scaffold strength, compliance, and elongation, concomitantly lowering the elastic modulus. Subsequently, a bilayer oriented polycaprolactone (PCL) scaffold infused with elastin is proposed. This design draws inspiration from the cellular arrangement of native blood vessels, leveraging oriented fibers to guide cell orientation. The resulting fiber scaffold exhibits commendable mechanical properties and cell infiltration capacity, imparting valuable insights for the rapid endothelialization of vascular scaffolds.

Electrospinning of Polycaprolactone Nanofibrous Scaffolds Containing Folic Acid for Nerve Tissue Engineering

Objective: The aim of the study was to employ electrospinning technology to fabricate aligned nanofibrous scaffolds of polycaprolactone (PCL) containing folic acid (FA) for nerve tissue engineering. Material and Methods: Scanning electron microscopy (SEM) was used to assess the diameter distribution and degree of alignment of the nanofibers. Fourier transform infrared spectroscopy (FTIR) and powder X-ray diffraction (PXRD) were used to analyze the chemical and crystalline structures of the scaffold. Additionally, the content and release behavior of FA in the PCL fibrous scaffolds were examined. Finally, the biocompatibility of the scaffolds was evaluated using rat Schwann cells, assessing cell proliferation, alignment, and morphology. Results: The study revealed that the nanofiber diameters ranged from 210.07 to 227.36 nm, and the scaffolds maintained an amorphous form with no effects on their chemical structure following the electrospinning process. The investigation demonstrated that PCL fibers could accommodate FA loading within a range of 99.25-102.49% w/w and that the release profile of FA followed Higuchi model. Moreover, the FA-containing PCL nanofibrous scaffolds significantly enhanced rat Schwann cell proliferation during the initial two days of culture when compared to a normal PCL nanofiber scaffold. The hydrophilic properties of folic acid are thought to have facilitated directional growth along the electrospun nanofibers, contributing to the observed results. Conclusion: Finally, PCL-containing FA nanofibrous scaffolds may be applicable to nerve tissue engineering.

Preparation and Characterization of Poliglecaprone-Incorporated Polycaprolactone Composite Fibrous Scaffolds

Electrospun fibrous scaffolds made from polymers such as polycaprolactone (PCL) have been used in drug delivery and tissue engineering for their viscoelasticity, biocompatibility, biodegradability, and tunability. Hydrophobicity and the prolonged degradation of PCL causes inhibition of the natural tissue-remodeling processes. Poliglecaprone (PGC), which consists of PCL and Poly (glycolic acid) (PGA), has better mechanical properties and a shorter degradation time compared to PCL. A blend between PCL and PGC called PPG can give enhanced shared properties for biomedical applications. In this study, we fabricated a blend of PCL and PGC nanofibrous scaffold (PPG) at different ratios of PGC utilizing electrospinning. We studied the physicochemical and biological properties, such as morphology, crystallinity, surface wettability, degradation, surface functionalization, and cellular compatibility. All PPG scaffolds exhibited good uniformity in fiber morphology and improved mechanical properties. The surface wettability and degradation studies confirmed that increasing PGC in the PPG composites increased hydrophilicity and scaffold degradation respectively. Cell viability and cytotoxicity results showed that the scaffold with PGC was more viable and less toxic than the PCL-only scaffolds. PPG fibers were successfully coated with polydopamine (PDA) and collagen to improve degradation, biocompatibility, and bioactivity. The nanofibrous scaffolds synthesized in this study can be utilized for tissue engineering applications such as for regeneration of human articular cartilage regeneration and soft bones.

Improvement of bioactivity with dual bioceramic incorporation to nanofibrous PCL scaffolds

Bone tissue injuries, diseases or related clinical interventions require bone tissue engineering (BTE) approaches for regeneration of large bone defects, especially for compromised situations. Most BTE applications in literature focused on composites of polymers with a single type of bioceramic. However, native bone matrix has various inorganic components. Accordingly, this study aimed to investigate the use of dual bioceramics in BTE scaffolds prepared by wet-electrospinning of Poly-caprolactone (PCL) and bioceramics; hydroxyapatite (HA), carbonated hydroxyapatite (CHA) and akermanite (AKR). After physicochemical characterizations of single and dual bioceramic-discs, it was found that AKR component should be at most 10% and thus, fibrous 3D composite scaffolds (PCL/HA; PCL/CHA; PCL/90HA/10AKR; PCL/90CHA/10AKR) were prepared. Scaffolds were then compared for degradation, swelling and microstructure properties. PCL/CHA, PCL/HA/AKR and PCL/CHA/AKR scaffolds improved apatite formation and presence of CHA, AKR or both in scaffolds increased Ca/P precipitation compared to HA involving scaffolds. Specifically, when two bioceramics were introduced, there was a noticeable increase in mineralization. No significant weight change was detected for scaffolds after two weeks of incubation. Presence of bioceramics in scaffolds significantly reduced swelling of PCL scaffolds with PCL/90HA10AKR and PCL/90CHA10AKR having higher swelling results than PCL/HA and PCL/CHA, respectively. Additionally, scaffolds with dual bioceramics (90HA10AKR, 90CHA10AKR) had higher cell proliferation for bone cells (Saos-2). In terms of osteogenic activity all groups showed increased ALP activity at 14 days compared to 7 days with PCL/CHA scaffolds having the highest value. Results suggests that newly developed PCL/90HA10AKR and PCL/90CHA10AKR composites hold potential for bone tissue engineering applications.

The biomedical potential of polycaprolactone nanofibrous scaffold containing titanium oxide for wound healing applications

The biomedical potential of polycaprolactone nanofibrous scaffold containing titanium oxide for wound healing applications

Guiding mesenchymal stem cells differentiation into chondrocytes using sulfated alginate/cold atmospheric plasma modified polycaprolactone nanofibrous scaffold

Using tissue engineering approaches is one of interesting strategies to repair cartilage injuries. This study reports the preparation of surface-modified electrospun polycaprolactone nanofibrous scaffolds with highly negatively-charged sulfated alginate as functional support for chondrogenic differentiation of mesenchymal stem cells. In this regard, polycaprolactone (PCL) nanofibers were fabricated by electrospinning, surface-activated by cold atmospheric plasma and further surface-modified with aqueous solutions of sulfated alginate. The scanning electron microscopy images showed the nanofibrous structure of electrospun PCL mats. The successful surface modification of PCL nanofibrous scaffolds with sulfated alginate was confirmed by the appearance of fingerprint region of mannuronic acid at 812 cm−1 in attenuated total reflectance Fourier transform infrared spectroscopy spectra. The cytocompatibility of the nanofibrous scaffolds for mesenchymal stem cells (MSCs) was confirmed using MTT assay. Reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemistry for type 2 COLLAGEN marker were conducted to confirm the chondrogenic differentiation of seeded MSCs on the surface of scaffolds. The expression of type 2 COLLAGEN by RT-PCR and immunocytochemistry analyses confirmed the chondrogenic differentiation of MSCs. Our results showed that sulfated alginate surface-modified PCL nanofibrous scaffold as an appropriate substrate for cell attachment and growth could promote the MSCs differentiate to chondrocytes.

Nano-hydroxyapatite-incorporated polycaprolactone nanofibrous scaffold as a dentin tissue engineering-based strategy for vital pulp therapy

ObjectivesTargeting a tissue engineering-based vital pulp therapy (VPT), this study investigated the incorporation of nano-hydroxyapatite (nHA) into polycaprolactone (PCL) nanofibers, and the metabolism of human dental pulp cells (HDPCs) seeded on the scaffolds. MethodsPCL-based solutions (10% w/v) containing nHA (0 – control; 0.5; 1.0; or 2.0% w/v) were electrospun into nanofibrous scaffolds. The scaffolds were characterized for morphology and composition (MEV/EDS), solubility, the release of calcium/phosphate (C/P), and modulation of medium pH. Then, HDPCs were seeded on the scaffolds and evaluated for cell viability (alamarBlue and live/dead), adhesion and spreading (F-actin), total protein (TP; Lowry), alkaline phosphatase activity (ALP; thymolphthalein assay), expression of odontogenic genes (RT-qPCR), and formation of a mineralized matrix (Alizarin Red). Data were analyzed with ANOVA and post-hocs (α = 5%). ResultsHigher nHA concentrations roughened fiber surfaces, whereas PCL+ 2%nHA increased the interfibrillar spaces. PCL+ 1%nHA or PCL+ 2%nHA significantly released more C/P but the medium pH was maintained below 8.0. HDPCs viability was not affected by nHA, while cell adhesion/spreading was favored, especially for PCL+ 2%nHA. Higher protein content and ALP activity were seen for scaffolds incorporated with nHA, after 21 days. PCL+ 1%nHA and PCL+ 2%nHA upregulated the expression of DSPP and DMP1 in 14 days, and COL1A1, ALPL, and DMP1 in 21 days. The formation of a mineralized matrix was nHA concentration-dependent, and it was about 9 × higher for PCL+ 2%nHA. SignificancenHA-incorporated PCL nanofibrous scaffolds are cytocompatible and can stimulate the adhesion and odontogenic potential of HDPCs. PCL+ 2%nHA formulation is a bioactive tissue engineering-based cell-homing strategy for VPT.

The biomedical potential of polycaprolactone nanofibrous scaffold containing titanium oxide for wound healing applications

The biomedical potential of polycaprolactone nanofibrous scaffold containing titanium oxide for wound healing applications

Biologically modified electrospun polycaprolactone nanofibrous scaffold promotes osteogenic differentiation

Tissue engineering has tried for decades to introduce scaffolds to replace the body's natural ECM, to replace damaged tissues that cannot be repaired or treated by conventional methods. In the present study, an attempt has been made to use human placental extract (PE) as a natural material to modify and simulate an electrospun Polycaprolactone (PCL) scaffold to the natural ECM. PCL and PCL-PE nanofibers were characterized morphologically, and their non-toxicity was also investigated. After that, their osteo-supportive capacities were also investigated by culture of the Wharton's jelly (WJ) derived mesenchymal stem cells (MSCs) on the scaffolds. SEM results demonstrated that PCL and PCL-PE scaffolds were fibrous with nanometer size, bead free and smooth, and these characteristics were not changed significantly while PCL nanofibers coated with PE. In addition, SEM results were also confirmed these scaffold's non-toxicity when WJ-MSCs properly attached, proliferated and expanded on the surface of scaffolds. Osteo-supportive capacity of the PCL and PCL-PE scaffolds was investigated via ALP activity, calcium content and bone-related gene expression in the WJ-MSCs when grown on the PCL and PCL-PE scaffolds and TCPS and TCPS-PE as controls. The results demonstrated that all bone related markers were significantly increased at the presence of the PE. In addition, this increase was significantly enhanced when PE combined with PCL nanofiber structure. According to the results, PCL-PE nanofibrous scaffold showed that it has a very high ability to support bone differentiation and can be introduced as a suitable candidate for use in bone tissue engineering.

Examining the Transmission of Visible Light through Electrospun Nanofibrous PCL Scaffolds for Corneal Tissue Engineering.

The transparency of nanofibrous scaffolds is of highest interest for potential applications like corneal wound dressings in corneal tissue engineering. In this study, we provide a detailed analysis of light transmission through electrospun polycaprolactone (PCL) scaffolds. PCL scaffolds were produced via electrospinning, with fiber diameters in the range from (35 ± 13) nm to (167 ± 35) nm. Light transmission measurements were conducted using UV–vis spectroscopy in the range of visible light and analyzed with respect to the influence of scaffold thickness, fiber diameter, and surrounding medium. Contour plots were compiled for a straightforward access to light transmission values for arbitrary scaffold thicknesses. Depending on the fiber diameter, transmission values between 15% and 75% were observed for scaffold thicknesses of 10 µm. With a decreasing fiber diameter, light transmission could be improved, as well as with matching refractive indices of fiber material and medium. For corneal tissue engineering, scaffolds should be designed as thin as possible and fabricated from polymers with a matching refractive index to that of the human cornea. Concerning fiber diameter, smaller fiber diameters should be favored for maximizing graft transparency. Finally, a novel, semi-empirical formulation of light transmission through nanofibrous scaffolds is presented.

Design and Characterization of Maltose-Conjugated Polycaprolactone Nanofibrous Scaffolds for Uterine Tissue Engineering

PurposeUterine anomalies are prevalent in women, and the major treatment assisted to them is hysterectomy as donor availability is extremely low. To overcome this, engineering uterine myometrium smooth muscle tissue has become very important. Several studies have shown that polycaprolactone (PCL) nanofibers are very effective in engineering smooth muscles, as this type of scaffold has structural similarities to the extracellular matrices of the cells. Here, we hypothesize that by electrospinning PCL nanofibers, they form a suitable scaffold for uterine tissue engineering.MethodsPolycaprolactone nanofibrous scaffolds were fabricated, and surface modification was performed following two step wet chemistry method. First step is aminolysis which introduces the primary amine groups on the PCL scaffolds following which maltose is conjugated on the scaffolds. This was confirmed by the ninhydrin assay for the presence of amine groups. This was followed by ELLA assay where the presence of maltose on the scaffold was quantified. Modified scaffolds were further characterized by scanning electron microscope (SEM), contact angle analysis and Fourier transform infrared spectroscopy (FTIR). MTT assay, live-dead assay and actin staining were performed on the maltose immobilization to study the improvement of the cell attachment and proliferation rates on the modified scaffolds.ResultsHuman uterine fibroblast (HUF) cells displayed significant proliferation on the maltose-modified PCL scaffolds, and they also exhibited appropriate morphology indicating that these modified fibers are highly suitable for uterine cell growth.ConclusionOur results indicate that the fabricated maltose PCL (MPCL) scaffolds would be a potential biomaterial to treat uterine injuries and promote regeneration.Lay Summary and Future WorkUterine anomalies are prevalent in women, and the major treatment is hysterectomy as donor availability is extremely low. Over the past few years, considerable efforts have been directed towards uterine tissue regeneration. This study is to design a tissue engineered scaffold that could act as a human uterine myometrial patch. We propose to create uterine fibroblast-based synthetic scaffolds that act in a condition similar to the intrauterine microenvironment where the embryos are embedded in the uterine wall. For understanding of the efficiency of the myometrial patch, functional characterization will be performed to study the effects of estrogen and prostaglandins on myometrial activity of the designed patch. Results from these experiments will assist a deeper understanding of how to construct a total bioengineered uterus which can substitute the uterus transplantation procedure, which nonetheless is in its initial stages of development.Graphical

Optimization of polycaprolactone - based nanofiber matrices for the cultivation of corneal endothelial cells

Posterior lamellar transplantation of the eye’ s cornea (DSAEK, DMEK) currently is the gold standard for treating patients with corneal endothelial cell and back surface pathologies resulting in functional impairment. An artificial biomimetic graft carrying human corneal endothelium could minimize the dependency on human donor corneas giving access to this vision-restoring surgery to large numbers of patients, thus reducing current long waiting lists. In this study, four groups of electrospun nanofibrous scaffolds were compared: polycaprolactone (PCL), PCL/collagen, PCL/gelatin and PCL/chitosan. Each of the scaffolds were tissue-engineered with human corneal endothelial cells (HCEC-B4G12) and analyzed with regard to their potential application as artificial posterior lamellar grafts. Staining with ZO-1 and Na+/K+-ATPase antibodies revealed intact cell functionalities. It could be shown, that blending leads to decreasing contact angle, whereby a heterogeneous blend morphology could be revealed. Scaffold cytocompatibility could be confirmed for all groups via live/dead staining, whereby a significant higher cell viability could be observed for the collagen and gelatine blended matrices with 97 ± 3% and 98 ± 2% living cells respectively. TEM images show the superficial anchoring of the HCECs onto the scaffolds. This work emphasizes the benefit of blended PCL nanofibrous scaffolds for corneal endothelial keratoplasty.

Assembly of porous graphitic carbon nitride nanosheets into electrospun polycaprolactone nanofibers for bone tissue engineering

Polycaprolactone (PCL) is a widely used synthetic biopolymer in the field of biomedical applications. However, poor hydrophilicity, slow degradation rate, and weak cellular responses have been made to limit its use. Hence, improving these properties is essential to recognize as a broadly acceptable biomaterial with enhanced cellular activities. For this purpose, porous g-C3N4 nanosheets incorporated PCL nanofibrous scaffolds were synthesized via the electrospinning method. The effect of g-C3N4 nanosheets into the PCL/g-C3N4 composite scaffolds was characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis/differential scanning calorimetry (TGA/DSC). Moreover, mechanical behaviors, contact angle, biodegradability, and biocompatibility were also evaluated. Our findings showed that porous g-C3N4 nanosheets decreased the overall fiber diameter of composite scaffolds while increasing mechanical properties, wettability, biodegradability, and improved bioactivity on MC3T3-E1 cells in in vitro test. Based on the obtained results, we suggest that PCL/g-C3N4 composite could potentially provide a new platform for bone tissue engineering application.

Electropsun Polycaprolactone Fibres in Bone Tissue Engineering: A Review.

Regeneration of bone tissue requires novel load bearing, biocompatible materials that support adhesion, spreading, proliferation, differentiation, mineralization, ECM production and maturation of bone-forming cells. Polycaprolactone (PCL) has many advantages as a biomaterial for scaffold production including tuneable biodegradation, relatively high mechanical toughness at physiological temperature. Electrospinning produces nanofibrous porous matrices that mimic many properties of natural tissue extracellular matrix with regard to surface area, porosity and fibre alignment. The biocompatibility and hydrophilicity of PCL nanofibres can be improved by combining PCL with other biomaterials to form composite scaffolds for bone regeneration. This work reviews the most recent research on synthesis, characterization and cellular response to nanofibrous PCL scaffolds and the composites of PCL with other natural and synthetic materials for bone tissue engineering.

Evaluation of Human Mesenchymal Stem Cells Differentiation to Neural Cells on Polycaprolactone Nanofiber Scaffolds

: Differentiation of human mesenchymal stem cells (hMSC) to neural cells on Nano-scaffolds is a promising method for the treatment of the damaged nervous system through bionanomaterial-cell transplantation. The hMSC’s multipotential features have been discovered in various tissue engineering researches. This investigation shows the in-vitro development and neural differentiation of hMSC in 3D and 2D environments. The 3D environment which used in this study is nanofibrous polycaprolactone (PCL). The differentiation potential of mesenchymal stem cells (MSCs) to neural cells, on the random polycaprolactone (PCL) nanofibrous scaffolds, and tissue plate was examined. Researches have proved that interaction of extracellular nanofibrous matrix with in-vivo cells, gives mechanical maintenance to the cells and plays a functional role in the control of cellular behaviour. Stem cells are developing as a fundamental tool in the evolution of tissue engineering and regenerative medication. PCL characterization was determined employing scanning electron microscopy (SEM). Agents like, retinoic acid, epidermal growth factor (EGF), fibroblast growth factor (FGF-2), and Ibmx, which they are neural inducing agents, added in DMDM/F12 to differentiate MSCs to neural cells. Reproduction of mesenchymal cells on PCL nanofibrous scaffolds and neural morphology revealed through a scanning electron microscope (SEM) and optical microscope outcomes. The differentiated mesenchymal cells on nanofibrous scaffolds express neural gene markers including; β- tubulin III and Map2 on the day of 14. Our investigation recommends the potential usage of differentiated neural cells from hMSCs on Nano-scaffolds toward the improvement of neural cells. This study conducted in 2011.

Smart Nanofibers with Natural Extracts Prevent Senescence Patterning in a Dynamic Cell Culture Model of Human Skin.

Natural cosmetic products have recently re-emerged as a novel tool able to counteract skin aging and skin related damages. In addition, recently achieved progress in nanomedicine opens a novel approach yielding from combination of modern nanotechnology with traditional treatment for innovative pharmacotherapeutics. In the present study, we investigated the antiaging effect of a pretreatment with Myrtus communis natural extract combined with a polycaprolactone nanofibrous scaffold (NanoPCL-M) on skin cell populations exposed to UV. We set up a novel model of skin on a bioreactor mimicking a crosstalk between keratinocytes, stem cells and fibroblasts, as in skin. Beta-galactosidase assay, indicating the amount of senescent cells, and viability assay, revealed that fibroblasts and stem cells pretreated with NanoPCL-M and then exposed to UV are superimposable to control cells, untreated and unexposed to UV damage. On the other hand, cells only exposed to UV stress, without NanoPCL-M pretreatment, exhibited a significantly higher yield of senescent elements. Keratinocyte-based 3D structures appeared disjointed after UV-stress, as compared to NanoPCL-M pretreated samples. Gene expression analysis performed on different senescence associated genes, revealed the activation of a molecular program of rejuvenation in stem cells pretreated with NanoPCL-M and then exposed to UV. Altogether, our results highlight a future translational application of NanoPCL-M to prevent skin aging.

Fabrication of Photo-Crosslinkable Poly(Trimethylene Carbonate)/Polycaprolactone Nanofibrous Scaffolds for Tendon Regeneration.

BackgroundThe treatment of tendon injuries remains a challenging problem in clinical due to their slow and insufficient natural healing process. Scaffold-based tissue engineering provides a promising strategy to facilitate tendon healing and regeneration. However, many tissue engineering scaffolds have failed due to their poor and unstable mechanical properties. To address this, we fabricated nanofibrous polycaprolactone/methacrylated poly(trimethylene carbonate) (PCL/PTMC-MA) composite scaffolds via electrospinning.Materials and MethodsPTMC-MA was characterized by nuclear magnetic resonance. Fiber morphology of composite scaffolds was evaluated using scanning electron microscopy. The monotonic tensile test was performed for determining the mechanical properties of composite scaffolds. Cell viability and collagen deposition were assessed via PrestoBlue assay and enzyme-linked immunosorbent assay, respectively.ResultsThese PCL/PTMC-MA composite scaffolds had an increase in mechanical properties as PTMC-MA content increase. After photo-crosslinking, they showed further enhanced mechanical properties including creep resistance, which was superior to pure PCL scaffolds. It is worth noting that photo-crosslinked PCL/PTMC-MA (1:3) composite scaffolds had a Young’s modulus of 31.13 ± 1.30 MPa and Max stress at break of 23.80 ± 3.44 MPa that were comparable with the mechanical properties of native tendon (Young’s modulus 20–1200 MPa, max stress at break 5–100 MPa). In addition, biological experiments demonstrated that PCL/PTMC-MA composite scaffolds were biocompatible for cell adhesion, proliferation, and differentiation.

Soy Protein Nanofiber Scaffolds for Uniform Maturation of Human Induced Pluripotent Stem Cell-Derived Retinal Pigment Epithelium.

Retinal pigment epithelium (RPE) differentiated from human induced pluripotent stem cells, called induced retinal pigment epithelium (iRPE), is being explored as a cell-based therapy for the treatment of retinal degenerative diseases, especially age-related macular degeneration. The success of RPE implantation is linked to the use of biomimetic scaffolds that simulate Bruch's membrane and promote RPE maturation and integration as a functional tissue. Due to difficulties associated with animal protein-derived scaffolds, including sterility and pro-inflammatory responses, current practices favor the use of synthetic polymers, such as polycaprolactone (PCL), for generating nanofibrous scaffolds. In this study, we tested the hypothesis that plant protein-derived fibrous scaffolds can provide favorable conditions permissive for the maturation of RPE tissue sheets in vitro. Our natural, soy protein-derived nanofibrous scaffolds exhibited a J-shaped stress-strain curve that more closely resembled the mechanical properties of native tissues than PCL with significantly higher hydrophilicity of the natural scaffolds, favoring in vivo implantation. We then demonstrate that iRPE sheets growing on these soy protein scaffolds are equivalent to iRPE monolayers cultured on synthetic PCL nanofibrous scaffolds. Immunohistochemistry demonstrated RPE-like morphology and functionality with appropriate localization of RPE markers RPE65, PMEL17, Ezrin, and ZO1 and with anticipated histotypic polarization of vascular endothelial growth factor and pigment epithelium-derived growth factor as indicated by enzyme-linked immunosorbent assay. Scanning electron microscopy revealed dense microvilli on the cell surface and homogeneous tight junctional contacts between the cells. Finally, comparative transcriptome analysis in conjunction with principal component analysis demonstrated that iRPE on nanofibrous scaffolds, either natural or synthetic, matured more consistently than on nonfibrous substrates. Taken together, our studies suggest that the maturation of cultured iRPE sheets for subsequent clinical applications might benefit from the use of nanofibrous scaffolds generated from natural proteins. Impact statement Induced retinal pigment epithelium (iRPE) from patient-derived induced pluripotent stem cells (iPSCs) may yield powerful treatments of retinal diseases, including age-related macular degeneration. Recent studies, including early human clinical trials, demonstrate the importance of selecting appropriate biomaterial scaffolds to support tissue-engineered iRPE sheets during implantation. Electrospun scaffolds show particular promise due to their similarity to the structure of the native Bruch's membrane. In this study, we describe the use of electroprocessed nanofibrous soy protein scaffolds to generate polarized sheets of human iPSC-derived iRPE sheets. Our evaluation, including RNA-seq transcriptomics, indicates that these scaffolds are viable alternatives to scaffolds electrospun from synthetic polymers.

Preparation of electrospun nanofibrous polycaprolactone scaffolds using nontoxic ethylene carbonate and glacial acetic acid solvent system

ABSTRACTIn recent years, solution electrospinning has attracted the interest of researchers due to the possibility to design nanofibrous scaffolds with large surface area to volume ratios. Polycaprolactone (PCL), because of its biocompatibility and easy processability, has been widely used to develop electrospun structures for tissue engineering. However, the use of organic solvents and the poor PCL solution stability still hinder the development of the solution electrospinning process. The relatively benign glacial acetic acid (GAC) as a solvent of PCL was used to fabricate microfibrous fibers or beaded fibers. Thus, ethylene carbonate (EC) as a nontoxic assistant solvent was added to the PCL/GAC solution to successfully fabricate electrospun nanofibrous PCL scaffolds. The stability of the PCL/GAC/EC solution system was demonstrated as the viscosity, which showed no significant change during 48 h. The ultrafine PCL fiber diameter decreased as EC concentration was increased from 0 to 9 vol% and started to slightly increase when EC concentration increased beyond 9 vol%. MTT assay evidenced that MC3T3‐E1 cells on the nanofibrous PCL scaffolds exhibited a better enhancement on cell proliferation. In summary, EC was added in PCL/GAC to establish a stable and low toxic solution electrospinning system, which provides promising strategy in tissue engineering field. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48387.