Polyethylene Terephthalate Scaffolds Research Articles

Additively manufactured polyethylene terephthalate scaffolds for scapholunate interosseous ligament reconstruction

The regeneration of the ruptured scapholunate interosseous ligament (SLIL) represents a clinical challenge. Here, we propose the use of a Bone-Ligament-Bone (BLB) 3D-printed polyethylene terephthalate (PET) scaffold for achieving mechanical stabilisation of the scaphoid and lunate following SLIL rupture. The BLB scaffold featured two bone compartments bridged by aligned fibres (ligament compartment) mimicking the architecture of the native tissue. The scaffold presented tensile stiffness in the range of 260 ± 38 N/mm and ultimate load of 113 ± 13 N, which would support physiological loading. A finite element analysis (FEA), using inverse finite element analysis (iFEA) for material property identification, showed an adequate fit between simulation and experimental data. The scaffold was then biofunctionalized using two different methods: injected with a Gelatin Methacryloyl solution containing human mesenchymal stem cell spheroids (hMSC) or seeded with tendon-derived stem cells (TDSC) and placed in a bioreactor to undergo cyclic deformation. The first approach demonstrated high cell viability, as cells migrated out of the spheroid and colonised the interstitial space of the scaffold. These cells adopted an elongated morphology suggesting the internal architecture of the scaffold exerted topographical guidance. The second method demonstrated the high resilience of the scaffold to cyclic deformation and the secretion of a fibroblastic related protein was enhanced by the mechanical stimulation. This process promoted the expression of relevant proteins, such as Tenomodulin (TNMD), indicating mechanical stimulation may enhance cell differentiation and be useful prior to surgical implantation. In conclusion, the PET scaffold presented several promising characteristics for the immediate mechanical stabilisation of disassociated scaphoid and lunate and, in the longer-term, the regeneration of the ruptured SLIL.

Wound healing by transplantation of mesenchymal stromal cells loaded on polyethylene terephthalate scaffold: Implications for skin injury treatment

BackgroundSeveral clinical studies have shown that cellular therapy based on mesenchymal stromal cells (MSCs) transplantation may accelerate wound healing. One major challenge is the delivery system used for MSCs transplantation. In this work, we evaluated the capacity of a scaffold based on polyethylene terephthalate (PET) to maintain the viability and biological functions of MSCs, in vitro. We examined the capacity of MSCs loaded on PET (MSCs/PET) to induce wound healing in an experimental model of full-thickness wound. MethodsHuman MSCs were seeded and cultured on PET membranes at 37 °C for 48 h. Adhesion, viability, proliferation, migration, multipotential differentiation and chemokine production were evaluated in cultures of MSCs/PET. The possible therapeutic effect of MSCs/PET on the re-epithelialization of full thickness wounds was examined at day 3 post-wounding in C57BL/6 mice. Histological and immunohistochemical (IH) studies were performed to evaluate wound re-epithelialization and the presence of epithelial progenitor cells (EPC). As controls, wounds without treatment or treated with PET were established. ResultsWe observed MSCs adhered to PET membranes and maintained their viability, proliferation and migration. They preserved their multipotential capacity of differentiation and ability of chemokine production. MSCs/PET implants promoted an accelerated wound re-epithelialization, after three days post-wounding. It was associated with the presence of EPC Lgr6+ and K6+. DiscussionOur results show that MSCs/PET implants induce a rapid re-epithelialization of deep- and full-thickness wounds. MSCs/PET implants constitute a potential clinical therapy for treating cutaneous wounds.

Comparison of the Biological Behaviour of Human Dermal Fibroblasts seeded on 3D Printed Polylactic acid, Polycaprolactone and Polyethylene Terephthalate Scaffolds in vitro

Regenerative medicine is a scientific field that improves and repairs diseased and injured tissues. Three-dimensional (3D) printing is an innovative technology that provides a new application field for regenerative medicine. 3D printed scaffolds by programming pore sizes and shapes serve as a temporary basis for cells until the natural extracellular matrix (ECM) is reconstructed. Dermal fibroblasts are mesenchymal cells located in the dermal skin layer that produce and organize ECM components. They play an essential role in skin wound healing and fibrosis. The aim of this study is to analyze the viability, adhesion, distribution, and collagen IV expression of human dermal fibroblasts (HDFs) seeded on 3D printed polylactic acid (PLA), polyethylene terephthalate (PET), and poly-ε-caprolactone (PCL) scaffolds in vitro. HDFs were seeded on scaffolds or tissue culture plastic plates as control and were cultured for 1 and 3 days. 3D PLA, PCL, and PET scaffolds were prepared using a custom made fused deposition modeling printer. The cell viability was measured by WST-1 assay on days 1 and 3. The cell adhesion was evaluated by scanning electron microscopy (SEM). The distribution was analyzed by hematoxylin and eosin (H&E) staining. Collagen IV expression was analyzed by immunohistochemical (IHC) staining. On day 1, the viability of HDFs on the 3D PLA scaffolds was significantly higher than PCL scaffolds. On day 3, the viability of HDFs on 3D PLA and PET scaffolds was significantly higher than PCL scaffolds. SEM images showed that HDFs on 3D PLA scaffolds attached the surfaces, filled the interfiber gaps and maintained their tissue specific morphology on day 3 compared to PCL and PET scaffolds. Histological images stained with H&E demonstrated that the distribution of HDFs on 3D PLA scaffolds was uniform on days 1 and 3. Collagen IV staining was more intense in HDFs on 3D PLA scaffolds on days 1 and 3. This study shows that 3D PLA scaffolds create a appropriate environment for cell viability, adhesion, distribution and may provide a high advantage in skin tissue regeneration.

Surgical Transplantation of Human RPE Stem Cell-Derived RPE Monolayers into Non-Human Primates with Immunosuppression.

SummaryRecent trials of retinal pigment epithelium (RPE) transplantation for the treatment of disorders such as age-related macular degeneration have been promising. However, limitations of existing strategies include the uncertain survival of RPE cells delivered by cell suspension and the inherent risk of uncontrolled cell proliferation in the vitreous cavity. Human RPE stem cell-derived RPE (hRPESC-RPE) transplantation can rescue vision in a rat model of retinal dystrophy and survive in the rabbit retina for at least 1 month. The present study placed hRPESC-RPE monolayers under the macula of a non-human primate model for 3 months. The transplant was able to recover in vivo and maintained healthy photoreceptors. Importantly, there was no evidence that subretinally transplanted monolayers underwent an epithelial-mesenchymal transition. Neither gliosis in adjacent retina nor epiretinal membranes were observed. These findings suggest that hRPESC-RPE monolayers are safe and may be a useful source for RPE cell replacement therapy.

Electrodeposition of calcium phosphate onto polyethylene terephthalate artificial ligament enhances graft-bone integration after anterior cruciate ligament reconstruction

It is a big challenge to develop a polyethylene terephthalate (PET) artificial ligament with excellent osteogenetic activity to enhance graft-bone integration for ligament reconstruction. Herein, we evaluated the effect of biomineralization (BM) and electrodeposition (ED) method for depositing calcium-phosphate (CaP) on the PET artificial ligament in vitro and in vivo. Scanning electron microscopy and energy-dispersive X-Ray spectrometer mapping analysis revealed that the ED-CaP had more uniform particles and element distribution (Ca, P and O), and thermogravimetric analysis showed there were more CaP on the PET/ED-CaP than the PET/BM-CaP scaffold. Moreover, the hydrophilicity of PET scaffolds was significantly improved after CaP deposition. In vitro study showed that CaP coating via BM or ED method could improve the attachment and proliferation of MC3T3-E1 cells, and ED-CaP coating significantly increased osteogenic differentiation of the cells, in which the Wnt/β-catenin signaling pathway might be involved. In addition, radiological, histological and immunohistochemical results of in vivo study in a rabbit anterior cruciate ligament (ACL) reconstruction model demonstrated that the PET/BM-CaP and PET/ED-CaP scaffolds significantly improved graft-bone integration process compared to the PET scaffold. More importantly, larger areas of new bone ingrowth and the formation of fibrocartilage tissue were observed at 12 weeks in the PET/ED-CaP group, and the biomechanical tests showed increased ultimate failure load and stiffness in PET/ED-CaP group compared to PET/BM-CaP and PET group. Therefore, ED of CaP is an effective strategy for the modification of PET artificial ligament and can enhance graft-bone integration both in vitro and in vivo.

Surface-transformed osteoinductive polyethylene terephthalate scaffold as a dual system for bone tissue regeneration with localized antibiotic delivery.

Multifunctional scaffolds have recently attained superior significance in tissue regeneration due to combinational activity profile that is usually accomplished by separate sequential therapy. Here, we present a dual system comprised of surface-phosphorylated PET fibrous matrix coated with ciprofloxacin-impregnated biodegradable polymer poly (hydroxyethyl methacrylate) aiming at regeneration of bone tissue deprived of bacterial infections, particularly osteomyelitis. The ATR, XPS and FESEM/EDX results provided confirmative evidences for surface phosphorylation of PET and in situ coating of the polymer. Swelling and contact angle measurements demonstrated improved hydrophilicity which is further corroborated by in vitro degradation profile in PBS. Preliminary evaluation by MTT and actin staining proved its biocompatibility while enhanced in vitro mineralization in 1.5X SBF by FESEM/EDX clearly indicate the primary nucleation and secondary growth of beautiful apatite crystals with Ca/P ratio similar to human bone. Alizarin red S and von Kossa staining validated the biomineralization in MG-63 cells. The sequential expression of early and late biomarkers -alkaline phosphatase (ALP) and osteocalcin (OSN)- of osteoblast differentiation in rat bone marrow mesenchymal cells (BMC) has demonstrated osteoinductive nature of the system. The second functionality of the scaffold has been proven by step-wise ciprofloxacin-release profile (in vitro) with ~60% release within 120h. In addition, antibacterial studies of ciprofloxacin- eluted from the scaffold have shown apparent zones of inhibition against Staphylococcus aureus (3.6±0.3cm) and Escherichia coli (3.0±0.8cm). Hence, the surface-transformed PET scaffold function as a dual system as localized antibiotic delivery vehicle against bone infections and undergo self-biomineralization leading to osteoinduction.

Arthroscopic Superior Capsular Reconstruction Using “Sandwich” Patch Technique for Irreparable Rotator Cuff Tears

The technique of superior capsular reconstruction (SCR) using fascia lata autograft, described by Mihata et al. in 2012, has been an acceptable and effective method for treating irreparable massive rotator cuff tears, especially in cases with severe fatty infiltration and tendon retraction. After the SCR procedure of Mihata et al., it was found that some graft failure occurred with thinning and elongation during the follow-up time, which was called graft “creep.” To avoid graft creep and reduce graft failure rates after SCR, we created an arthroscopic SCR technique with a “sandwich” patch augmented with polyethylene terephthalate scaffold interspaced between 2 folded layers of fascia lata autograft.

Bone Marrow Stem Cells-Seeded Polyethylene Terephthalate Scaffold in Repair and Regeneration of Rabbit Achilles Tendon.

The objective of this study was to evaluate the effect of bone marrow stem cells (BMSCs)-seeded polyethylene terephthalate (PET) scaffold for Achilles tendon repair in a rabbit model. The allogeneic BMSCs were seeded onto the PET scaffold and cultured in vitro for 14 days. Sixteen mature New Zealand rabbits underwent surgery to establish a 2-cm Achilles tendon defect model. The BMSCs-seeded PET scaffold was implanted into the defect of one limb (BMSCs-PET group), while the PET scaffold without BMSCs was implanted into the defect of contralateral limb as the control (PET group). All rabbits were sacrificed at 6 and 12 weeks after surgery. At 12 weeks after surgery, macroscopic and histological results showed formation of tendon-like tissues, and the structure was more mature in the BMSCs-PET group. Immunohistochemical analysis and real-time polymerase chain reaction (RT-PCR) demonstrated that the collagen I and collagen III were significantly higher in the BMSCs-PET group compared with those in the PET group. Mechanically, both the failure load and the average stiffness were significantly higher in the BMSCs-PET group than those in the PET group. In conclusion, BMSCs-seeded PET scaffold could effectively facilitate the healing process after being implanted in a rabbit Achilles tendon defect model.

Morphological Analysis of Biocompatibility of Autologous Bone Marrow Mononuclear Cells with Synthetic Polyethylene Terephthalate Scaffold.

We studied the properties of a tissue-engineered trachea consisting of a polyethylene terephthalate scaffold populated with autologous bone marrow mononuclear cells. The tissue-engineered constructs were obtained before surgery, during the postoperative period, and during autopsy. Cytomorphological analysis during the postoperative period showed the presence of mesenchymal stem cells on the inner surface of the implant on day 3 after surgery and cells of the respiratory epithelium on day 10-14. In autopsy samples, single epithelial cells, endothelial cells, and basal cells were found. Biocompatibility of the tissue-engineered trachea with autologous mononuclear cells of the patient was demonstrated.

Silk-based anisotropical 3D biotextiles for bone regeneration.

Bone loss in the craniofacial complex can been treated using several conventional therapeutic strategies that face many obstacles and limitations. In this work, novel three-dimensional (3D) biotextile architectures were developed as a possible strategy for flat bone regeneration applications. As a fully automated processing route, this strategy as potential to be easily industrialized. Silk fibroin (SF) yarns were processed into weft-knitted fabrics spaced by a monofilament of polyethylene terephthalate (PET). A comparative study with a similar 3D structure made entirely of PET was established. Highly porous scaffolds with homogeneous pore distribution were observed using micro-computed tomography analysis. The wet state dynamic mechanical analysis revealed a storage modulus In the frequency range tested, the storage modulus values obtained for SF-PET scaffolds were higher than for the PET scaffolds. Human adipose-derived stem cells (hASCs) cultured on the SF-PET spacer structures showed the typical pattern for ALP activity under osteogenic culture conditions. Osteogenic differentiation of hASCs on SF-PET and PET constructs was also observed by extracellular matrix mineralization and expression of osteogenic-related markers (osteocalcin, osteopontin and collagen type I) after 28 days of osteogenic culture, in comparison to the control basal medium. The quantification of convergent macroscopic blood vessels toward the scaffolds by a chick chorioallantoic membrane assay, showed higher angiogenic response induced by the SF-PET textile scaffolds than PET structures and gelatin sponge controls. Subcutaneous implantation in CD-1 mice revealed tissue ingrowth's accompanied by blood vessels infiltration in both spacer constructs. The structural adaptability of textile structures combined to the structural similarities of the 3D knitted spacer fabrics to craniofacial bone tissue and achieved biological performance, make these scaffolds a possible solution for tissue engineering approaches in this area.

Local delivery of controlled-release simvastatin to improve the biocompatibility of polyethylene terephthalate artificial ligaments for reconstruction of the anterior cruciate ligament.

The Ligament Advanced Reinforcement System has recently been widely used as the primary graft of choice in anterior cruciate ligament (ACL) reconstruction. But the biological graft–bone healing still remains a problem. Previous studies have shown that simvastatin (SIM) stimulates bone formation. The objective of this study was to investigate whether surface coating with collagen containing low-dose SIM microsphere could enhance the surface biocompatibility of polyethylene terephthalate (PET) artificial ligaments to accelerate graft-to-bone healing. The in vitro studies demonstrated that bone marrow stromal cells on the collagen-coated PET scaffolds (COL/PET) and simvastatin/collagen-coated PET scaffolds (SIM/COL/PET) proliferated vigorously. Compared with the PET group and the COL/PET group, SIM could induce bone marrow stromal cells’ osteoblastic differentiation, high alkaline phosphatase activity, more mineralization deposition, and more expression of osteoblast-related genes, such as osteocalcin, runt-related transcription factor 2, bone morphogenetic protein-2, and vascular endothelial growth factor, in the SIM/COL/PET group. In vivo, rabbits received ACL reconstruction with different scaffolds. Histological analysis demonstrated that graft–bone healing was significantly greater with angiogenesis and osteogenesis in the SIM/COL/PET group than the other groups. In addition, biomechanical testing at the eighth week demonstrated a significant increase in the ultimate failure load and stiffness in the SIM/COL/PET group. The low dose of SIM-sustained release from SIM/COL/PET promoted the graft–bone healing via its effect on both angiogenesis and osteogenesis. This study suggested that collagen containing low-dose SIM microsphere coating on the surface of PET artificial ligaments could be potentially applied for ACL reconstruction.

Design and Validation of a Cyclic Strain Bioreactor to Condition Spatially-Selective Scaffolds in Dual Strain Regimes

The objective of this study was to design and validate a unique bioreactor design for applying spatially selective, linear, cyclic strain to degradable and non-degradable polymeric fabric scaffolds. This system uses a novel three-clamp design to apply cyclic strain via a computer controlled linear actuator to a specified zone of a scaffold while isolating the remainder of the scaffold from strain. Image analysis of polyethylene terephthalate (PET) woven scaffolds subjected to a 3% mechanical stretch demonstrated that the stretched portion of the scaffold experienced 2.97% ± 0.13% strain (mean ± standard deviation) while the unstretched portion experienced 0.02% ± 0.18% strain. NIH-3T3 fibroblast cells were cultured on the PET scaffolds and half of each scaffold was stretched 5% at 0.5 Hz for one hour per day for 14 days in the bioreactor. Cells were checked for viability and proliferation at the end of the 14 day period and levels of glycosaminoglycan (GAG) and collagen (hydroxyproline) were measured as indicators of extracellular matrix production. Scaffolds in the bioreactor showed a seven-fold increase in cell number over scaffolds cultured statically in tissue culture plastic petri dishes (control). Bioreactor scaffolds showed a lower concentration of GAG deposition per cell as compared to the control scaffolds largely due to the great increase in cell number. A 75% increase in hydroxyproline concentration per cell was seen in the bioreactor stretched scaffolds as compared to the control scaffolds. Surprisingly, little differences were experienced between the stretched and unstretched portions of the scaffolds for this study. This was largely attributed to the conditioned and shared media effect. Results indicate that the bioreactor system is capable of applying spatially-selective, linear, cyclic strain to cells growing on polymeric fabric scaffolds and evaluating the cellular and matrix responses to the applied strains.

Expansion of human amniotic fluid stem cells in 3-dimensional fibrous scaffolds in a stirred bioreactor

Human amniotic fluid stem cells (AFSCs) are emerging as an important cell source for tissue engineering and regenerative medicine due to their easy accessibility and broad multi-potentiality. In clinical applications, a large number of human AFSCs are required, which cannot be provided in conventional 2-dimensional (2-D) culture systems. To address this issue, the expansion of human AFSCs in 3-dimensional (3-D) polyethylene terephthalate (PET) scaffolds in a stirred bioreactor was evaluated. The results showed that 3-D PET scaffold with in vivo-like environment and a large specific surface area for cell adhesion promoted cell expansion (66-fold vs. 38-fold) compared to 2-D culture. A dynamic fibrous bed bioreactor (FBB) was used to expand AFSCs to reach a high cell density of 3.2×106cells/mL. The bioreactor-expanded cells maintained clonogenic ability and high levels of expression (95.5–99.8%) of characteristic stem cell surface makers, including CD29, CD44, CD90 and CD105. The differentiation of bioreactor-expanded AFSCs into osteogenic and adipogeneic lineages was demonstrated with Alizarin red S and Oil Red O staining, respectively, and further confirmed by reverse transcriptase polymerase chain reaction (RT-PCR) analysis. This study demonstrated the feasibility of using the FBB to mass-produce human AFSCs for potential applications in tissue engineering and regenerative medicine.

Multiwalled carbon nanotube-coated polyethylene terephthalate fibrous matrices for enhanced neuronal differentiation of mouse embryonic stem cells.

The next-generation of tissue scaffolds should incorporate 3-D structures with nanofeatures. Fibrous polyethylene terephthalate (PET) matrices have been widely studied as tissue engineering scaffolds, but their performance is limited by the lack of nanotopography. Carbon nanotubes can provide nanoscale structures similar to those present in natural extracellular matrices in vivo, but are difficult to use as 3-D scaffolds for tissue engineering. In this study, multiwalled carbon nanotubes (MWCNTs) were used to coat and provide nanofeatures on the surface of PET membranes and fibers. The effects of MWCNTs on the cellular functions of mouse embryonic stem (mES) cells cultured on the nanoengineered PET surface and 3-D scaffolds were investigated. In general, MWCNTs promoted cell adhesion and proliferation of mES cells while maintaining excellent cell viability in the growth medium. Neuronal differentiation was also significantly enhanced when cells were cultured in the differentiation medium. Different cell morphologies were observed in the presence of MWCNTs. Cells were stretched and well spread out in MWCNT-coated PET scaffolds, whereas cells were sporadically distributed in non-coated PET scaffolds. Furthermore, more filopodia were formed in MWCNT-coated PET matrices, suggesting increased interactions between scaffolds and cells. Also, neuronal cells differentiated from mES cells in the 3-D nanoengineered PET scaffolds formed extensive nerve networks around each fiber and neurite bridges between fibers. These findings suggest that MWCNTs can provide nanofeatures on PET fibrous matrices and enhance their performance as 3-D nanoengineered tissue engineering scaffolds.

A non-damaging chemical amination protocol for poly(ethylene terephthalate) - application to the design of functionalized compliant vascular grafts.

Bioengineering approaches have been intensively applied to create small diameter vascular grafts using artificial materials. However, a fully successful, high performing and anti-thrombogenic structure has not been achieved yet. In this study, we present the first step of a process aiming at biofunctionalizing previously designed compliant polyethylene terephthalate (PET) scaffolds (Moreno et al., 2011). The main challenge of such a surface modification is to prevent the bulk polymer from any damage, so that it preserves the mechanical properties that the structures have been designed for. In that endeavor, an aminated long-chain polymer (polyvinylamine, PVAm) was used as an aminolysis reagent to get amine (-NH2) moieties only on the very surface of PET. Different reaction conditions were assayed, leading to a large range of amino group densities associated with slight variations of the planar tensile properties. These results were in stark contrast with those generated with a common small diamine substrate (ethylenediamine, EtDA), as the latter yielded a strong degradation of the mechanical properties for comparable amine densities. Tubular mechanical assays were then carried out on PVAm-functionalized PET scaffolds. The latter showed a compliance match with arteries under the chosen reaction conditions, as initially observed for pristine PET tubular scaffolds.

RETRACTED: Viability and proliferation of rat MSCs on adhesion protein-modified PET and PU scaffolds

In 2011, the first in-man successful transplantation of a tissue engineered trachea-bronchial graft, using a synthetic POSS-PCU nanocomposite construct seeded with autologous stem cells, was performed. To further improve this technology, we investigated the feasibility of using polymers with a three dimensional structure more closely mimicking the morphology and size scale of native extracellular matrix (ECM) fibers. We therefore investigated the in vitro biocompatibility of electrospun polyethylene terephthalate (PET) and polyurethane (PU) scaffolds, and determined the effects on cell attachment by conditioning the fibers with adhesion proteins. Rat mesenchymal stromal cells (MSCs) were seeded on either PET or PU fiber-layered culture plates coated with laminin, collagen I, fibronectin, poly-d-lysine or gelatin. Cell density, proliferation, viability, morphology and mRNA expression were evaluated. MSC cultures on PET and PU resulted in similar cell densities and amounts of proliferating cells, with retained MSC phenotype compared to data obtained from tissue culture plate cultures. Coating the scaffolds with adhesion proteins did not increase cell density or cell proliferation. Our data suggest that both PET and PU mats, matching the dimensions of ECM fibers, are biomimetic scaffolds and, because of their high surface area-to-volume provided by the electrospinning procedure, makes them per se suitable for cell attachment and proliferation without any additional coating.

Mechanical evaluation and cell response of woven polyetheretherketone scaffolds

Polyetheretherketone (PEEK) is a high performance polymer, with high melting temperature and high resistance to wear. PEEK biomedical devices are typically manufactured to produce nonflexible structures. In this study, we fabricated flexible PEEK scaffolds from multifilament and monofilament yarns, using weaving technologies. Scaffolds were compared for structural and mechanical properties, and assessed for in vitro biological response to L929 mouse fibroblast cells. PEEK scaffolds were found to support fibroblast cell attachment and proliferation, with similar cell numbers to a polyethylene terephthalate scaffold. The large pores (261-280 μm) of the monofilament scaffold prevented pore coverage by cells, confining cells to filaments, whereas the smaller pores (81-100 μm) of the multifilament scaffold permitted partial pore coverage. Poor cell adhesion, due to large filament curvature angles, created a checkered pattern on the woven surface, a previously undocumented phenomenon. The multifilament scaffold was found to be lighter, thinner, and less porous, with better mechanical properties (load at break: 657 N, elastic recovery: 66%, burst strength: 492 N) than the monofilament scaffold (load at break: 534 N, elastic recovery: 30%, burst strength: 401 N). Results indicate that flexible PEEK woven structures may find application as tissue engineering scaffolds, particularly for engineering soft tissues.

Enhanced cell growth using non-woven scaffolds of multilobal fibres

Multilobal fibres contain several grooves and have higher surface area than round fibres. Cell density can be enhanced when cultured on scaffolds manufactured with multilobal fibres. This study compared the cell growth of dermal fibroblasts and osteoblast-like SaOS2 cells on polymeric scaffolds produced from multilobal fibres to the conventional round-fibred scaffolds. Cells were cultured on round nylon 6,6, trilobal nylon 6,6, round polyethylene terephthalate (PET) and multilobal PET scaffolds for 14 days. There were more cells cultured on trilobal nylon 6,6 and PET multilobal scaffolds than their round counterparts. Preference to the type of multilobal scaffolds was cell dependent. Fibroblasts increased by 21.8 ± 1.9 fold to 6.3 × 105 cells ( p < 0.001) when cultured on trilobal nylon 6,6 scaffolds while SaOS2 cells exhibited a 16.7 ± 2.8 fold increase (2.9 × 105 cells, p < 0.001) on the multilobal PET scaffolds after 14 days of culture. The ability of multilobal fibres to accommodate large quantities of cells presents an excellent alternative to round fibres as scaffolds for tissue engineering.

Modeling Tissue Growth Within Nonwoven Scaffolds Pores

In this study we present a novel approach for predicting tissue growth within the pores of fibrous tissue engineering scaffolds. Thin nonwoven polyethylene terephthalate scaffolds were prepared to characterize tissue growth within scaffold pores, by mouse NR6 fibroblast cells. On the basis of measurements of tissue lengths at fiber crossovers and along fiber segments, mathematical models were determined during the proliferative phase of cell growth. Tissue growth at fiber crossovers decreased with increasing interfiber angle, with exponential relationships determined on day 6 and 10 of culture. Analysis of tissue growth along fiber segments determined two growth profiles, one with enhanced growth as a result of increased tissue lengths near the fiber crossover, achieved in the latter stage of culture. Derived mathematical models were used in the development of a software program to visualize predicted tissue growth within a pore. This study identifies key pore parameters that contribute toward tissue growth, and suggests models for predicting this growth, based on fibroblast cells. Such models may be used in aiding scaffold design, for optimum pore infiltration during the tissue engineering process.

Benzalkonium Chloride Sterilization of Nonwoven Fibrous Scaffolds for Astrocyte Culture

Tissue engineering is an emerging field in biomedicine, holding enormous promise for regenerative medicine. Scaffolds, within which cells proliferate, are a controlling factor in tissue engineering applications. Upon fabrication, tissue scaffolds must undergo appropriate sterilization to eliminate contaminants. Current sterilization methods are either costly, time consuming, or ineffective. In this study, a quaternary salt, benzalkonium chloride (BAC), was used as a chemical agent for sterilization of nonwoven polyethylene terephthalate (PET) fibers and polylactic acid nanofibers. Treating the PET scaffolds with 0.1% (w/v) BAC for only 2 minutes was effective to eliminate bacterial contaminants in the fibrous matrices. In addition, astrocyte cells were successfully cultured in the PET scaffolds following BAC sterilization, demonstrating the suitability of BAC as a sterilization agent. This chemical sterilization method is also mild and nonabrasive to nanostructured materials such as electrospun polylactic acid nanofibers.