Suture Retention Strength Research Articles

Supercritical carbon dioxide decellularised pericardium: Mechanical and structural characterisation for applications in cardio-thoracic surgery.

Many biomaterials are used in cardio-thoracic surgery with good short-term results. However, calcification, dehiscence, and formation of scar tissue are reported. The aim of this research is to characterise decellularised pericardium after supercritical carbon dioxide (scCO2) processing as an alternative biological material for uses in cardio-thoracic surgery. Porcine and bovine pericardium were decellularised using scCO2. Mechanical properties such as tensile strength, elastic modulus, fracture toughness and suture retention strength were determined. Ultrastructure was visualised using Scanning Electron Microscopy. Water uptake and swelling was experimentally determined. Commercially available glutaraldehyde treated bovine pericardium was used as gold standard for comparison. scCO2 decellularised porcine (and bovine pericardium) maintained their tensile strength compared to untreated native pericardium (13.3 ± 2.4MPa vs 14.0 ± 4.1MPa, p = 0.73). Tensile strength of glutaraldehyde treated pericardium was significantly higher compared to untreated pericardium (19.4 ± 7.3MPa vs 10.2 ± 2.2MPa, p = 0.02). Suture retention strength of scCO2 treated pericardium was significantly higher than glutaraldehyde treated pericardium (p = 0.01). We found no anisotropy of scCO2 or glutaraldehyde treated pericardium based on a trouser tear test. Ultrastructure was uncompromised in scCO2 treated pericardium, while glutaraldehyde treated pericardium showed deterioration of extracellular matrix. scCO2 processing preserves initial mechanical and structural properties of porcine and bovine pericardium, while glutaraldehyde processing damages the extracellular matrix of bovine pericardium. Decellularisation of tissue using scCO2 might give long-term solutions for cardio-thoracic surgery without compromising initial good mechanical properties.

Living nanofiber yarn-based woven biotextiles for tendon tissue engineering using cell tri-culture and mechanical stimulation.

Tendon grafts are essential for the treatment of various tendon-related conditions due to the inherently poor healing capacity of native tendon tissues. In this study, we combined electrospun nanofiber yarns with textile manufacturing strategies to fabricate nanofibrous woven biotextiles with hierarchical features, aligned fibrous topography, and sufficient mechanical properties as tendon tissue engineered scaffolds. Comparing to traditional electrospun random or aligned meshes, our novel nanofibrous woven fabrics possess strong tensile and suture-retention strengths and larger pore size. We also demonstrated that the incorporation of tendon cells and vascular cells promoted the tenogenic differentiation of the engineered tendon constructs, especially under dynamic stretch. This study not only presents a novel tissue engineered tendon scaffold fabrication technique but also provides a useful strategy to promote tendon differentiation and regeneration.

The suture retention test, revisited and revised.

A systematic investigation of the factors affecting the suture retention test is performed. The specimen width w and the distance a of the suture bite from the specimen free edge emerge as the most influential geometrical parameters. A conservative approach for the quantification of suture retention strength is identified, based on the use of a camera to monitor the incipient failure and detect the instant of earliest crack propagation. The corresponding critical force, called break starting strength, is extremely robust against test parameter variations and its dependence on the specimen geometry becomes negligible when a≥ 2mm and w≥ 10mm. Comparison of suture retention and mode I crack opening tests reveals a linear correlation between break starting strength and tearing energy. This suggests that the defect created by the needle and the load applied by the suture thread lead to a fracture mechanics problem, which dominates the initiation of failure.

Evaluation of electrospinning parameters on the tensile strength and suture retention strength of polycaprolactone nanofibrous scaffolds through surface response methodology

Scaffolds should provide sufficient biomechanical support during tissue regeneration for tissue engineering (TE) applications. Electrospun scaffolds are commonly applied in TE applications due to their tunable physical, chemical, and mechanical properties as well as their similarity to extracellular matrix. Although the mechanical properties of electrospun scaffolds are highly dependent on processing parameters, a limited number of studies have systematically investigated this subject. The present study has investigated the effects of the main electrospinning parameters on tensile and suture retention strength of polycaprolactone (PCL) scaffolds using response surface methodology. Scaffolds morphology and cell-scaffold interaction were also investigated in this study. According to the fitted model, polymer concentration and feed rate have the most significant positive effect on both the tensile and suture retention strength. Whereas applied voltage negatively affected both the tensile and suture retention strength. The effect of distance on tensile strength was not significant while its effect on suture retention was different depending on its values. Changes in biomechanical properties were associated with gross alterations in morphology of the fibers and cell-scaffold interaction. Scaffolds with lowest tensile strength presented a beaded morphology while scaffolds with higher tensile strength presented beadless morphology with worm-like fibers. The increase in tensile strength was correlated with the increase in average diameter of the fibers and pore size. The results of cell culture study showed that fibroblasts stretched and proliferated more on scaffolds with lower tensile strength. The generated model might be helpful when PCL scaffold with desirable tensile and suture retention strength are required. Furthermore, the results suggest that changes in morphology and subsequent cell-scaffold interaction should be considered when these biomechanical properties are optimized.

In Vitro Mechanical Property Evaluation of Chitosan-Based Hydrogels Intended for Vascular Graft Development.

Vascular grafts made of synthetic polymers perform poorly in cardiac and peripheral bypass applications. In these applications, chitosan-based materials can be produced and shaped to provide a novel scaffold for vascular tissue engineering. The goal of this study was to evaluate in vitro the mechanical properties of a novel chitosan formulation to assess its potential for this scaffold. Two chitosan-based hydrogel tubes were produced by modulating chitosan concentration. Based on the standard ISO 7198:1998, the hydrogel tubes were characterized in vitro in terms of suture retention strength, tensile strength, compliance, and burst pressure. By increasing chitosan concentration, suture retention value increased to reach 1.1N; average burst strength and elastic moduli also increased significantly. The compliance seemed to exhibit a low value for chitosan tubes of high concentration. By modulating chitosan concentration, we produced scaffolds with suitable mechanical properties to be implanted in vivo and withstand physiological blood pressures.

A Biomimetic Heparinized Composite Silk-Based Vascular Scaffold with sustained Antithrombogenicity

Autologous grafts, as the gold standard for vascular bypass procedures, associated with several problems that limit their usability, so tissue engineered vessels have been the subject of an increasing number of works. Nevertheless, gathering all of the desired characteristics of vascular scaffolds in the same construct has been a big challenge for scientists. Herein, a composite silk-based vascular scaffold (CSVS) was proposed to consider all the mechanical, structural and biological requirements of a small-diameter vascular scaffold. The scaffold’s lumen composed of braided silk fiber-reinforced silk fibroin (SF) sponge covalently heparinized (H-CSVS) using Hydroxy-Iron Complexes (HICs) as linkers. The highly porous SF external layer with pores above 60 μm was obtained by lyophilization. Silk fibers were fully embedded in scaffold’s wall with no delamination. The H-CSVS exhibited much higher burst pressure and suture retention strength than native vessels while comparable elastic modulus and compliance. H-CSVSs presented milder hemolysis in vitro and significant calcification resistance in subcutaneous implantation compared to non-heparinized ones. The in vitro antithrombogenic activity was sustained for over 12 weeks. The cytocompatibility was approved using endothelial cells (ECs) and vascular smooth muscle cells (SMCs) in vitro. Therefore, H-CSVS demonstrates a promising candidate for engineering of small-diameter vessels.

Synthesis of cell composite alginate microfibers by microfluidics with the application potential of small diameter vascular grafts

Fabrication of small diameter vascular grafts (SDVGs) with appropriate responses for clinical application is still challenging. In the present work, the production and characterization of solid alginate based microfibers as potential SDVG candidates through the method of microfluidics were considered original. A simple glass microfluidic device with a ‘L-shape’ cylindrical-flow channel in the microfluidic platform was developed. The gelation of microfibers occurred when the alginate solution and a CaCl2 solution were introduced as a core flow and as a sheath flow, respectively. The diameters of the microfibers could be controlled by varying the flow rates and the glass capillary tubes diameters at their tips. The generated microfibers had somewhat rough and porous surfaces, their suture retention strengths were comparable to the strength of other tissue engineered grafts. The encapsulated mesenchymal stem cells proliferated well in the microfibers, and showed a stable endothelialization under the angiogenesis effects of vascular endothelial growth factor and fibroblastic growth factor. The in vivo implant into the mice abdomens indicated that cell composite microfibers caused a mild host reaction. These encouraging results suggest great promise of the application of microfluidics as a future alternative in SDVGs engineering.

Turkey model for flexor tendon research: in vitro comparison of human, canine, turkey, and chicken tendons

BackgroundFlexor tendon injuries are one of the most common hand injuries and remain clinically challenging for functional restoration. Canine and chicken have been the most commonly used animal models for flexor tendon–related research but possess several disadvantages. The purpose of this study was to explore a potential turkey model for flexor tendon research. MethodsThe third digit from human cadaveric hands, canine forepaws, turkey foot, and chicken foot were used for this study. Six digits in each of four species were studied in detail, comparing anatomy of the flexor apparatus, joint range of motioņ tendon excursion, tendon cross-sectional area, work of flexion, gliding resistance at the level of the A2 pulley, modulus of elasticity, suture retention strength, and histology across species. ResultsAnatomically, the third digit in the four species displayed structural similarities; however, the tendon cross-sectional area of the turkey and human were similar and larger than canine and chicken. Furthermore, the turkey digit resembles the human's finger with the lack of webbing between digits, similar vascularization, tendon excursion, work of flexion, gliding resistance, mechanical properties, and suture holding strength. More importantly, human and turkey tendons were most similar in histological appearance. ConclusionsTurkey flexor tendons have many properties that are comparable to human flexor tendons which would provide a clinically relevant, economical, nonhuman companion large animal model for flexor tendon research.

Coaxial electrospinning multicomponent functional controlled-release vascular graft: Optimization of graft properties

Small diameter vascular grafts possessing desirable biocompatibility and suitable mechanical properties have become an urgent clinic demand. Herein, heparin loaded fibrous grafts of collagen/chitosan/poly(l-lactic acid-co-ε-caprolactone) (PLCL) were successfully fabricated via coaxial electrospinning. By controlling the concentration of heparin and the ratio of collagen/chitosan/PLCL, most grafts had the heparin encapsulation efficiency higher than 70%, and the heparin presented sustained release for more than 45 days. Particularly, such multicomponent grafts had relative low initial burst release, and after heparin releasing for 3 weeks, the grafts still showed good anti-platelet adhesion ability. In addition, along with the excellent cell biocompatibility, the fabricated grafts possessed suitable mechanical properties including good tensile strength, suture retention strength, burst pressure and compliance which could well match the native blood vessels. Thus, the optimized graft properties could be properly addressed for vascular tissue application via coaxial electrospinning.

Braided and Stacked Electrospun Nanofibrous Scaffolds for Tendon and Ligament Tissue Engineering.

Tendon and ligament injuries are a persistent orthopedic challenge given their poor innate healing capacity. Nonwoven electrospun nanofibrous scaffolds composed of polyesters have been used to mimic the mechanics and topographical cues of native tendons and ligaments. However, nonwoven nanofibers have several limitations that prevent broader clinical application, including poor cell infiltration, as well as tensile and suture-retention strengths that are inferior to native tissues. In this study, multilayered scaffolds of aligned electrospun nanofibers of two designs-stacked or braided-were fabricated. Mechanical properties, including structural and mechanical properties and suture-retention strength, were determined using acellular scaffolds. Human bone marrow-derived mesenchymal stem cells (MSCs) were seeded on scaffolds for up to 28 days, and assays for tenogenic differentiation, histology, and biochemical composition were performed. Braided scaffolds exhibited improved tensile and suture-retention strengths, but reduced moduli. Both scaffold designs supported expression of tenogenic markers, although the effect was greater on braided scaffolds. Conversely, cell infiltration was superior in stacked constructs, resulting in enhanced cell number, total collagen content, and total sulfated glycosaminoglycan content. However, when normalized against cell number, both designs modulated extracellular matrix protein deposition to a similar degree. Taken together, this study demonstrates that multilayered scaffolds of aligned electrospun nanofibers supported tenogenic differentiation of seeded MSCs, but the macroarchitecture is an important consideration for applications of tendon and ligament tissue engineering.

Corneal regeneration by utilizing collagen based materials

Corneal disease is the main cause of blindness and keratoplasty is the only widely accepted treatment. Shortage of donor tissue makes the biomaterials for corneal regeneration a hot area of research. Collagen is the main component of corneal stroma, so collagen becomes a promising material for corneal repair. However, due to the drawbacks of collagen, it needs to be further modified to satisfy the requirement of corneal regeneration. In this article, we highlight the importance of collagen materials for corneal repair, and summarize several methods of preparing collagen based corneal regeneration materials, including chemical crosslinking, plastic compression of collagen, and collagen vitrigel. These modification methods can make collagen membranes with remarkable properties such as enough mechanical and suture retention strength, antibacterial property and excellent optical property. These materials may provide potential treatment for corneal disease.

Augmented repair of radial meniscus tear with biomimetic electrospun scaffold: an in vitro mechanical analysis.

BackgroundLarge radial tears that disrupt the circumferential fibers of the meniscus are associated with reduced meniscal function and increased risk of joint degeneration. Electrospun fibrous scaffolds can mimic the topography and mechanics of fibrocartilaginous tissues and simultaneously serve as carriers of cells and growth factors, yet their incorporation into clinically relevant suture repair techniques for radial meniscus tears is unexplored. The purposes of this study were to (1) evaluate the effect of fiber orientation on the tensile properties and suture-retention strength of multilayered electrospun scaffolds and (2) determine the mechanical effects of scaffold inclusion within a surgical repair of a simulated radial meniscal tear. The experimental hypothesis was that augmentation with a multilayered scaffold would not compromise the strength of the repair.MethodsThree multilayered electrospun scaffolds with different fiber orientations were fabricated–aligned, random, and biomimetic. The biomimetic scaffold was comprised of four layers in the following order (deep to superficial)–aligned longitudinal, aligned transverse, aligned longitudinal, and random–respectively corresponding to circumferential, radial, circumferential, and superficial collagen fibers of the native meniscus. Material properties (i.e., ultimate stress, modulus, etc.) of the scaffolds were determined in the parallel and perpendicular directions, as was suture retention strength. Complete radial tears of lateral bovine meniscus explants were repaired with a double horizontal mattress suture technique, with or without inclusion of the biomimetic scaffold sheath. Both repair groups, as well as native controls, were cyclically loaded between 5 and 20 N for 500 cycles and then loaded to failure. Clamp-to-clamp distance (i.e., residual elongation) was measured following various cycles. Ultimate load, ultimate elongation, and stiffness, were also determined. Group differences were evaluated by one-way ANOVA or Student’s t-test where appropriate.ResultsAligned scaffolds possessed the most anisotropic mechanical properties, whereas random scaffolds showed uniform properties in the parallel and perpendicular directions. In comparison, the biomimetic scaffold possessed moduli in the parallel (68.7 ± 14.7 MPa) and perpendicular (39.4 ± 11.6 MPa) directions that respectively approximate the reported circumferential and radial tensile properties of native menisci. The ultimate suture retention load of the biomimetic scaffold in the parallel direction (7.2 ± 1.6 N) was significantly higher than all other conditions (p < 0.001). Biomimetic scaffold augmentation did not compromise mechanical properties when compared against suture repair in terms of residual elongation after 500 cycles (scaffold: 5.05 ± 0.89 mm vs. repair: 4.78 ± 1.24 mm), ultimate failure load (137.1 ± 31.0 N vs. 124.4 ± 21.4 N), ultimate elongation (12.09 ± 5.89 mm vs. 10.14 ± 4.61 mm), and stiffness (20.8 ± 3.6 vs. 18.4 ± 4.7 N/mm).ConclusionsWhile multilayered scaffold sheets were successfully fabricated to mimic the ultrastructure and anisotropic tensile properties of native menisci, improvements in suture retention strength or adoption of superior surgical techniques will be needed to further enhance the mechanical strength of repairs of radial meniscal tears.

Trilayered sulfated silk fibroin vascular grafts enhanced with braided silk tube

The scaffold component is a major barrier to the development of a clinically useful small-diameter tissue-engineered vascular graft. Scaffold requirements include matching the mechanical and structural properties with those of native vessels and optimizing the microenvironment for cell integration, adhesion, and growth. Trilayered sulfated silk fibroin graft was developed to mimic native tissue structure and function. Physical properties and cell studies were assessed to evaluate the viability of their usage in small-diameter tissue-engineered vascular grafts. Compared with previously fabricated silk fibroin vascular grafts, these trilayered grafts provided comparable water permeability, tensile strength, burst pressure, as well as suture retention strength, to saphenous veins for vascular grafts. In addition, the in vitro results showed good cytocompatibility of the trilayered grafts. These physical and cellular outcomes indicate potential utility of these trilayered sulfated silk fibroin grafts for small-diameter vascular grafts.

A novel suture retention test for scaffold strength characterization in ophthalmology

Sutures are a common way to attach scaffolds in patients. For tubular cardiac scaffolds, the ‘suture retention strength’ is commonly used to evaluate the resistance of a scaffold against the pull-out of a suture. In order to make this quantity accessible for ophthalmological scaffolds the test procedure has been modified in a novel way. Polycaprolactone (PCL) films of different thicknesses and an amniotic membrane (AM) were used for the experiments. Circular samples with a radius of 7mm were taken and a suture was passed through each sample and tied to a loop. The sample was clamped in a tensile tester and a bolt was passed through the loop. The suture was then pulled with a constant deformation rate until pull-out occurred. The suture retention strength, the deformation at the suture retention strength, and the deformation at rupture were determined for each sample. The presented modified suture retention test allows to measure the relevant parameters of samples on the scale of ophthalmological scaffolds in a reproducible way. A comparison between the first data on PCL and AM has been made.

Electrospun silk fibroin/poly (L-lactide-ε-caplacton) graft with platelet-rich growth factor for inducing smooth muscle cell growth and infiltration.

The construction of a smooth muscle layer for blood vessel through electrospinning method plays a key role in vascular tissue engineering. However, smooth muscle cells (SMCs) penetration into the electrospun graft to form a smooth muscle layer is limited due to the dense packing of fibers and lack of inducing factors. In this paper, silk fibroin/poly (L-lactide-ε-caplacton) (SF/PLLA-CL) vascular graft loaded with platelet-rich growth factor (PRGF) was fabricated by electrospinning. The in vitro results showed that SMCs cultured in the graft grew fast, and the incorporation of PRGF could induce deeper SMCs infiltrating compared to the SF/PLLA-CL graft alone. Mechanical properties measurement showed that PRGF-incorporated graft had proper tensile stress, suture retention strength, burst pressure and compliance which could match the demand of native blood vessel. The success in the fabrication of PRGF-incorporated SF/PLLA-CL graft to induce fast SMCs growth and their strong penetration into graft has important application for tissue-engineered blood vessels.

Using in situ nanocellulose-coating technology based on dynamic bacterial cultures for upgrading conventional biomedical materials and reinforcing nanocellulose hydrogels.

Bacterial nanocellulose (BNC) is a microbial nanofibrillar hydrogel with many potential applications. Its use is largely restricted by insufficient strength when in a highly swollen state and by inefficient production using static cultivation. In this study, an in situ nanocellulose-coating technology created a fabric-frame reinforced nanocomposite of BNC hydrogel with superior strength but retained BNC native attributes. By using the proposed technology, production time could be reduced from 10 to 3 days to obtain a desirable hydrogel sheet with approximately the same thickness. This novel technology is easier to scale up and is more suitable for industrial-scale manufacture. The mechanical properties (tensile strength, suture retention strength) and gel characteristics (water holding, absorption and wicking ability) of the fabric-reinforced BNC hydrogel were investigated and compared with those of ordinary BNC hydrogel sheets. The results reveal that the fabric-reinforced BNC hydrogel was equivalent with regard to gel characteristics, and exhibited a qualitative improvement with regard to its mechanical properties. For more advanced applications, coating technology via dynamic bacterial cultures could be used to upgrade conventional biomedical fabrics, i.e. medical cotton gauze or other mesh materials, with nanocellulose. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1077-1084, 2016.

Mechanical evaluation of gradient electrospun scaffolds with 3D printed ring reinforcements for tracheal defect repair

Tracheal stenosis can become a fatal condition, and current treatments include augmentation of the airway with autologous tissue. A tissue-engineered approach would not require a donor source, while providing an implant that meets both surgeons’ and patients’ needs. A fibrous, polymeric scaffold organized in gradient bilayers of polycaprolactone (PCL) and poly-lactic-co-glycolic acid (PLGA) with 3D printed structural ring supports, inspired by the native trachea rings, could meet this need. The purpose of the current study was to characterize the tracheal scaffolds with mechanical testing models to determine the design most suitable for maintaining a patent airway. Degradation over 12 weeks revealed that scaffolds with the 3D printed rings had superior properties in tensile and radial compression, with at least a three fold improvement and 8.5-fold improvement, respectively, relative to the other scaffold groups. The ringed scaffolds produced tensile moduli, radial compressive forces, and burst pressures similar to or exceeding physiological forces and native tissue data. Scaffolds with a thicker PCL component had better suture retention and tube flattening recovery properties, with the monolayer of PCL (PCL-only group) exhibiting a 2.3-fold increase in suture retention strength (SRS). Tracheal scaffolds with ring reinforcements have improved mechanical properties, while the fibrous component increased porosity and cell infiltration potential. These scaffolds may be used to treat various trachea defects (patch or circumferential) and have the potential to be employed in other tissue engineering applications.

Development of an in-process UV-crosslinked, electrospun PCL/aPLA-co-TMC composite polymer for tubular tissue engineering applications

Cardiovascular diseases remain the largest cause of death worldwide, and half of these deaths are the result of failure of the vascular system. Tissue engineering promises to provide new, and potentially more effective therapeutic strategies to replace damaged or degenerated vessels with functional vessels. However, these engineered vessels have substantial performance criteria, including vessel-like tubular shape, structure and mechanical property slate. Further, whether implanted without or with prior in vitro culture, such tubular scaffolds must provide a suitable environment for cell adhesion and growth and be of sufficient porosity to permit cell colonization. This study investigates the fabrication of slowly degradable, composite tubular polymer scaffolds made from polycaprolactone (PCL) and acrylated l-lactide-co-trimethylene carbonate (aPLA-co-TMC). The addition of acrylate groups permits the ‘in-process’ formation of crosslinks between aPLA-co-TMC chains during electrospinning of the composite system, exemplifying a novel process to produce multicomponent, elastomeric electrospun polymer scaffolds. Although PCL and aPLA-co-TMC were miscible in a co-solvent, a criteria for electrospinning, due to thermodynamic incompatibility of the two polymers as melts, solvent evaporation during electrospinning drove phase separation of these two systems, producing ‘core-shell’ fibres, with the core being composed of PCL, and the shell of crosslinked elastomeric aPLA-co-TMC. The resulting elastic fibrous scaffolds displayed burst pressures and suture retention strengths comparable with human arteries. Cytocompatibility testing with human mesenchymal stem cells confirmed adhesion to, and proliferation on the three-dimensional fibrous network, as well as alignment with highly-organized fibres. This new processing methodology and resulting mechanically-robust composite scaffolds hold significant promise for tubular tissue engineering applications. Statement of SignificanceAutologous small diameter blood vessel grafts are unsuitable solutions for vessel repair. Engineered solutions such as tubular biomaterial scaffolds however have substantial performance criteria to meet, including vessel-like tubular shape, structure and mechanical property slate. We detail herein an innovative methodology to co-electrospin and ‘in-process’ crosslink composite mixtures of Poly(caprolactone) and a newly synthesised acrylated-Poly(lactide-co-trimethylene-carbonate) to create elastomeric, core-shell nanofibrous porous scaffolds in a one-step process. This novel composite system can be used to make aligned scaffolds that encourage stem cell adhesion, growth and morphological control, and produce robust tubular scaffolds of tunable internal diameter and wall thickness that possess mechanical properties approaching those of native vessels, ideal for future applications in the field of vessel tissue engineering.

Mechanical behavior of bilayered small-diameter nanofibrous structures as biomimetic vascular grafts

To these days, the production of a small diameter vascular graft (<6mm) with an appropriate and permanent response is still challenging. The mismatch in the grafts mechanical properties is one of the principal causes of failure, therefore their complete mechanical characterization is fundamental. In this work the mechanical response of electrospun bilayered small-diameter vascular grafts made of two different bioresorbable synthetic polymers, segmented poly(ester urethane) and poly(L-lactic acid), that mimic the biomechanical characteristics of elastin and collagen is investigated. A J-shaped response when subjected to internal pressure was observed as a cause of the nanofibrous layered structure, and the materials used. Compliance values were in the order of natural coronary arteries and very close to the bypass gold standard-saphenous vein. The suture retention strength and burst pressure values were also in the range of natural vessels. Therefore, the bilayered vascular grafts presented here are very promising for future application as small-diameter vessel replacements.

A small diameter silk fibroin tubular scaffold for artificial blood vessel

Event Abstract Back to Event A small diameter silk fibroin tubular scaffold for artificial blood vessel Jiannan Wang1, Xiaolong Sun1, Qiongyu Wang1 and Yue Wu1 1 Soochow University, National Engineering Laboratory for Modern Silk, China Silk fibroin is increasingly used for tissue engineering applications, as it has excellent cytocompatibility, tissue affinity and biodegradability compared with synthetic materials. A novel biomimetic silk fibroin small-diameter tubular scaffold (SFTS) was designed with three distinct layers: a regenerated SF intima, a silk braided media and a regenerated SF adventitia. The SFTS exhibited even silk fibroin penetration throughout the braid, forming a porous layered tube expecting to endow superior mechanical, permeable and cell adhesion properties that are beneficial to vascular regeneration. The SFTS had good stress-strain resistance when combined with the silk knit medium. The axial breaking strength was >840 kPa, and breaking elongation could reach about 75%; the circumferential breaking strength was >16 MPa and breaking elongation was over 350%. The results of compression testing showed that the radial compression resilience of SFTS was about 95%, which was a significant improvement on artificial blood vessels prepared from Dacron. Furthermore, the Yong’s modulus of the SFTS was 0.2–0.3 MPa, which is comparable to native human common carotid artery (0.1–1.0MPa). The suture retention strength was about 23 N. Cell compatibility was assays on fibroblasts, human umbilical vein endothelial cells and smooth muscle cells. Cell morphology, viability and proliferation were satisfactory for vascular cells determined by DNA content assay, MTT assay, scanning electron microscopy and confocal microscopy. HE staining and immunohistochemical analysis showed the SFTS had good histocompatibility. After 3 months of SFTSs transplantation in rabbit’ common carotid artery, relatively complete endodermis covered on the inner surface of SFTSs without obvious endometrium hyperplasia. After one year of SFTSs transplantation, hysterosalpinography result showed open blood flow. Collectively, these data demonstrate that the SFTS possesses the satisfactory cytocompatibility, hemocompatibility, and excellent mechanical properties for use as vascular scaffolds as an alternative to vascular autografts, finally realizing the vascular reconstruction. Acknowledgements This work was supported by National Natural Science Foundation of China (No. 51473108), Natural Science Foundation of Jiangsu Province of China (No. BK20141210), Science and Technology Plan Foundation of Suzhou of China (No. SS201341). Refences [1] J. N. Wang, Y. L. Wei, H. G. Yi, et al. Materials Science and Engineering C, 2014, 34: 429–436. [2] Y. L. Wei, D. Sun, H. G. Yi, et al. Textile Research Journal, 2014, 84: 959-967. Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016. Presentation Type: Poster Topic: Biomaterials in constructing tissue substitutes Citation: Wang J, Sun X, Wang Q and Wu Y (2016). A small diameter silk fibroin tubular scaffold for artificial blood vessel. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.02582 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 27 Mar 2016; Published Online: 30 Mar 2016. Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Jiannan Wang Xiaolong Sun Qiongyu Wang Yue Wu Google Jiannan Wang Xiaolong Sun Qiongyu Wang Yue Wu Google Scholar Jiannan Wang Xiaolong Sun Qiongyu Wang Yue Wu PubMed Jiannan Wang Xiaolong Sun Qiongyu Wang Yue Wu Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.