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Regulation of nerve cells using conductive nanofibrous scaffolds for controlled release of Lycium barbarum polysaccharides and nerve growth factor. Regen Biomater 2023; 10:rbad038. [PMID: 37215435 PMCID: PMC10196224 DOI: 10.1093/rb/rbad038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 04/01/2023] [Accepted: 04/11/2023] [Indexed: 05/24/2023] Open
Abstract
Currently, more and more patients suffer from peripheral nerve injury due to trauma, tumor and other causes worldwide. Biomaterial-based nerve conduits are increasingly recognized as a potential alternative to nerve autografts for the treatment of peripheral nerve injury. However, an ideal nerve conduit must offer topological guidance and biochemical and electrical signal transduction mechanisms. In this work, aligned conductive nanofibrous scaffolds comprising polylactic-co-glycolic acid and multiwalled carbon nanotubes (MWCNTs) were fabricated via coaxial electrospinning, and nerve growth factor (NGF) and Lycium barbarum polysaccharides (LBP) purified from the wolfberry were loaded on the core and shell layers of the nanofibers, respectively. LBP were confirmed to accelerate long-distance axon regeneration after severe peripheral nerve injury. In addition, the synergistic promotion of LBP and NGF on nerve cell proliferation and neurite outgrowth was demonstrated. MWCNTs were introduced into the aligned fibers to further increase the electrical conductivity, which promoted the directional growth and neurite extension of neurons in vitro. Further, the combination of conductive fibrous scaffolds with electrical stimulation that mimics endogenous electric fields significantly promoted the differentiation of PC12 cells and the axon outgrowth of neurons. Based on robust cell-induced behaviors, conductive composite fibers with optimized fiber alignment may be used for the promotion of nerve recovery.
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Current Advancements and Strategies of Biomaterials for Tendon Repair: A Review. FRONT BIOSCI-LANDMRK 2023; 28:66. [PMID: 37114544 DOI: 10.31083/j.fbl2804066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/27/2023] [Accepted: 03/08/2023] [Indexed: 04/29/2023]
Abstract
Tendon is a bundle of tissue comprising of a large number of collagen fibers that connects muscle to bone. However, overuse or trauma may cause degeneration and rupture of the tendon tissues, which imposes an enormous health burden on patients. In addition to autogenous and allogeneic transplantation, which is commonly used in the clinic, the current research on tendon repair is focused on developing an appropriate scaffold via biomaterials and fabrication technology. The development of a scaffold that matches the structure and mechanics of the natural tendon is the key to the success of the repair, so the synergistic optimization of the scaffold fabrication technology and biomaterials has always been a concern of researchers. A series of strategies include the preparation of scaffolds by electrospinning and 3D printing, as well as the application of injectable hydrogels and microspheres, which can be used individually or in combination with cells, growth factors for tendon repair. This review introduces the tendon tissue structure, the repair process, the application of scaffolds, and the current challenges facing biomaterials, and gives an outlook on future research directions. With biomaterials and technology continuing to be developed, we envision that the scaffolds could have an important impact on the application of tendon repair.
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Evaluation of Natural Protein-based Nanofiber Composite Photocrosslinking Hydrogel for skin wound regeneration. Colloids Surf B Biointerfaces 2023; 226:113292. [PMID: 37028231 DOI: 10.1016/j.colsurfb.2023.113292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 03/27/2023] [Accepted: 04/02/2023] [Indexed: 04/05/2023]
Abstract
Protein based photocrosslinking hydrogels with nanofiber dispersions were reported to be an effective wound dressing. In this study, two kinds of protein (gelatin and decellularized dermal matrix) were modified to obtain GelMA and ddECMMA, respectively. Poly(ε-caprolactone) nanofiber dispersions (PCLPBA) and thioglycolic acid-modified chitosan (TCS) were added into GelMA solution and ddECMMA solution, respectively. After photocrosslinking, four kinds of hydrogel (GelMA, GTP4, DP and DTP4) were fabricated. The hydrogels showed excellent physico-chemical property, biocompatibility and negligible cytotoxicity. When applied on the full-thickness cutaneous deficiency of SD rats, hydrogel treated groups exhibited an enhanced wound healing effect than Blank group. Besides, the histological staining of H&E and Masson's showed that hydrogels groups with PCLPBA and TCS (GTP4 and DTP4) improved wound healing. Furthermore, GTP4 group performed better healing effect than other groups, which had great potential in skin wound regeneration.
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Synthesis of oxidized sodium alginate and its electrospun bio-hybrids with zinc oxide nanoparticles to promote wound healing. Int J Biol Macromol 2023; 232:123480. [PMID: 36720331 DOI: 10.1016/j.ijbiomac.2023.123480] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 01/22/2023] [Accepted: 01/26/2023] [Indexed: 01/30/2023]
Abstract
Electrospun fibers provide a promising platform for wound healing; however, they lack requisite characteristics for wound repair, including antibacterial and anti-inflammatory properties and angiogenic ability. Sodium alginate (SA) is being used for different types of applications. However, the poor spinnability of SA restricts its applications. The objectives of this study were three-fold: a) to synthesize oxidized sodium alginate (OSA) to improve its spinnability, b) to fabricate composite fibrous membranes by blending OSA along with zinc oxide nanoparticles (ZnO-NPs), and c) to decipher antibacterial and anti-inflammatory properties as well as biocompatibility of membranes in vitro and in vivo. OSA displaying different oxidation degrees (Dox (%)) was synthesized by varying the molar ratio of sodium periodate to SA. OSA (Dox, ∼48 %) afforded smooth and uniform fibers; 0.5 wt% of adipic dihydrazide (ADH) evolved into structurally stable and water-insoluble membranes. Composite fibrous membranes containing 2 wt% of ZnO-NPs displayed good biocompatibility and bactericidal effect against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in vitro. In addition, composite membranes showed remarkable epithelialization, neovascularization, and anti-inflammatory response than that of the membranes devoid of ZnO-NPs. Conclusively, these composite fibrous membranes may have broad implications for wound healing applications.
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On the Development of Modular Polyurethane-based Bioelastomers for Rapid Hemostasis and Wound Healing. Regen Biomater 2023; 10:rbad019. [PMID: 36969314 PMCID: PMC10038391 DOI: 10.1093/rb/rbad019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 02/24/2023] [Accepted: 03/04/2023] [Indexed: 03/11/2023] Open
Abstract
Abstract
Massive hemorrhage may be detrimental to the patients, which necessitates the advent of new materials with high hemostatic efficiency and good biocompatibility. The objective of this research was to screen for the effect of the different types of bio-elastomers as hemostatic dressings. Three-dimensional (3D) loose nanofiber sponges were prepared; PU-TA/Gel showed promising potential. Polyurethane (PU) was synthesized and electrospun to afford porous sponges, which were crosslinked with glutaraldehyde (GA). FTIR and 1H-NMR evidenced the successful synthesis of PU. The prepared PU-TA/Gel sponge had the highest porosity and water absorption ratio. Besides, PU-TA/Gel sponges exhibited cytocompatibility, negligible hemolysis, and the shortest clotting time. PU-TA/Gel sponge rapidly induced stable blood clots with shorter hemostasis time and less bleeding volume in a liver injury model in rats. Intriguingly, PU-TA/Gel sponges also induced good skin regeneration in a full-thickness excisional defect model as revealed by the histological analysis. These results showed that the PU-TA/Gel based sponges may offer an alternative platform for hemostasis and wound healing.
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Composite Superelastic Aerogel Scaffolds Containing Flexible SiO
2
Nanofibers Promote Bone Regeneration (Adv. Healthcare Mater. 15/2022). Adv Healthc Mater 2022. [DOI: 10.1002/adhm.202270094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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A photocrosslinking antibacterial decellularized matrix hydrogel with nanofiber for cutaneous wound healing. Colloids Surf B Biointerfaces 2022; 217:112691. [PMID: 35834997 DOI: 10.1016/j.colsurfb.2022.112691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 06/20/2022] [Accepted: 07/04/2022] [Indexed: 12/23/2022]
Abstract
ddECMMA is the methacrylating product of decellularized dermal extracellular matrix with biological signals and capable of photocrosslinking. Thiolated chitosan (TCS) is an effective antibacterial component. PCLPBA is a kind of plasma-treated polycaprolactone nanofiber dispersions (PCLP) that regulates macrophage polarization and promotes angiogenesis. In this study, we obtained ddECMMA via methacrylation reaction. TCS was prepared by reaction between chitosan and thioglycolic acid. PCLPBA was fabricated via reaction between PCLP and 3-buten-1-amine. TCS and PCLPBA were mixed in ddECMMA solution and photocrosslinked to form DTP4 hydrogel. The hydrogel showed rapid gelation, good mechanical strength, antibacterial and antioxidant properties. When it was cocultured with NIH 3T3 cells, the cells showed good morphology and proliferation rate. After applying it to the full-thickness cutaneous wound, wounds almost healed in 2 weeks via re-epithelialization and neovascularization with negligible scar tissue. The results indicate that DTP4 hydrogel is a promising candidate for clinic skin wound healing.
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Synergistic effect of glucagon-like peptide-1 analogue liraglutide and ZnO on the antibacterial, hemostatic, and wound healing properties of nanofibrous dressings. J Biosci Bioeng 2022; 134:248-258. [PMID: 35760699 DOI: 10.1016/j.jbiosc.2022.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 11/17/2022]
Abstract
Bacterial infections and poor vascularization delay wound healing, thus necessitating alternative strategies for functional wound dressings. Zinc oxide (ZnO) has been shown to exert a potent antibacterial effect against bacterial species. Similarly, Glucagon-like peptide-1 (GLP-1) analogue liraglutide (LG) has been shown to promote vascularization and improve wound healing. The objective of this research was to investigate the synergistic effect of ZnO nanoparticles (ZnO-NPs) and LG to simultaneously induce antibacterial, hemostatic, and vascularization effects for infected wound healing. Electrospun poly (l-lactide-co-glycolide)/gelatin (PLGA/Gel) membranes containing ZnO-NPs and LG displayed good biocompatibility and hemostatic ability. Both, ZnO-NPs and LG exhibited synergistic antibacterial effect against Staphylococcus aureus and Escherichia coli as well as improved the migration and tubule-like network formation of human umbilical vein endothelial cells (HUVECs) in vitro. Once evaluated in a bacterial-infected wound model in rats, the membranes loaded with ZnO-NPs and LG effectively promoted wound healing causing significant reduction in wound area and scar-like tissue formation. Therefore, ZnO-NPs/LG synergism may offer an invaluable solution for the treatment of poorly healing infected wounds.
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Composite Superelastic Aerogel Scaffolds Containing Flexible SiO 2 Nanofibers Promote Bone Regeneration. Adv Healthc Mater 2022; 11:e2200499. [PMID: 35670086 DOI: 10.1002/adhm.202200499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 04/25/2022] [Indexed: 11/08/2022]
Abstract
Repairing irregular-shaped bone defects poses enormous challenges. Scaffolds that can fully fit the defect site and simultaneously induce osteogenesis and angiogenesis hold great promise for bone defect healing. This study aimed to produce superelastic organic/inorganic composite aerogel scaffolds by blending silica nanofibers (SiO2 ) and poly (lactic acid)/gelatin (PLA/gel) nanofibers; the content of SiO2 nanofibers were varied from 0-60 wt% (e.g., PLA/gel, PLA/gel/SiO2 -L, PLA/gel/SiO2 -M, and PLA/gel/SiO2 -H for 0%, 20%, 40%, and 60% of SiO2 nanofibers, respectively) to produce a range of scaffolds. The PLA/gel/SiO2 -M scaffold had excellent elasticity and good mechanical properties. In vitro experiments demonstrated that the silicon ions released from PLA/gel/SiO2 -M scaffolds could promote the differentiation of rat bone marrow-derived mesenchymal stem cells (rBMSCs) into osteoblasts, thereby enhancing alkaline phosphatase activity and bone-related genes expressions. Meanwhile, the released silicon ions also promoted the proliferation of human umbilical vein endothelial cells (HUVECs) and the expression of vascular endothelial growth factors, thereby promoting angiogenesis. The assessment of these scaffolds in a calvarial defect model in rats showed good potential of PLA/gel/SiO2 -M to induce bone regeneration as well as promote osteogenesis and angiogenesis. Overall, these superelastic scaffolds containing flexible SiO2 nanofibers can simultaneously induce osteogenesis and angiogenesis, which may have broad applications for tissue engineering applications. This article is protected by copyright. All rights reserved.
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Prodrug inspired bi-layered electrospun membrane with properties of enhanced tissue integration for guided tissue regeneration. J Biomed Mater Res B Appl Biomater 2022; 110:2050-2062. [PMID: 35322549 DOI: 10.1002/jbm.b.35059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 03/01/2022] [Accepted: 03/12/2022] [Indexed: 11/09/2022]
Abstract
Guided tissue regeneration (GTR) membranes play a vital role in periodontal surgery. Recently a series of composite electrospun membranes have been fabricated to improve the unexpected biodegradation of collagen-based GTR membranes. However, their tissue integrity needs to be studied in depth. In this study, a bi-layered electrospun membrane (BEM) inspired by "prodrug" was fabricated, which contained a dense-layer (BEM-DL) and a potential loose-layer (BEM-LL). The nanofibers of BEM-DL were composed of poly(l-lactic-co-glycolic acid) and tilapia skin collagen (TSC). Whereas the BEM-LL consisted of two types of nanofibers, one was the same as BEM-DL and the other was made from TSC. The morphology, degradation in vitro, cytocompatibility and biocompatibility in rats were investigated with a poly(lactic-co-glycolic acid) electrospun membrane (PLGA) as the negative control. The pore size of BEM-LL soaked for 7 days became larger than the original sample (164.8 ± 90.9 and 52.5 ± 21.0 μm2 , respectively), which was significantly higher (p < .05) than that of BEM-DL and PLGA. The BEM-LL displayed a larger weight loss rate of 82.3 ± 3.6% than the BEM-DL of 46.0 ± 2.8% at day 7 because of the rapid degradation of TSC fibers. The cytocompatibility test demonstrated that L929 cells were only spread on the surface of the BEM-DL while MC3T3-E1 cells grew into the BEM-LL layer. The subcutaneous implantation test further proved that BEM-DL performed as a cellular barrier, whereas BEM-LL was conducive to cell infiltration as deep as 200 μm with reduced fibrous encapsulation. Herein, the BEM inspired by "prodrug" is a promising GTR membrane with a property of enhanced tissue integration.
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Converging 3D Printing and Electrospinning: Effect of Poly(l-lactide)/Gelatin Based Short Nanofibers Aerogels on Tracheal Regeneration. Macromol Biosci 2021; 22:e2100342. [PMID: 34706143 DOI: 10.1002/mabi.202100342] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Revised: 10/13/2021] [Indexed: 12/28/2022]
Abstract
Recently, various tissue engineering based strategies have been pursued for the regeneration of tracheal tissues. However, previously developed tracheal scaffolds do not accurately mimic the microstructure and mechanical behavior of the native trachea, which restrict their clinical translation. Here, tracheal scaffolds are fabricated by using 3D printing and short nanofibers (SF) dispersion of poly(l-lactide)/gelatin (0.5-1.5 wt%) to afford tracheal constructs. The results display that the scaffolds containing 1.0 wt % of SF exhibit low density, good water absorption capacity, reasonable degradation rate, and stable mechanical properties, which were comparable to the native trachea. Moreover, the designed scaffolds possess good biocompatibility and promote the growth and infiltration of chondrocytes in vitro. The biocompatibility of tracheal scaffolds is further assessed after subcutaneous implantation in mice for up to 4 and 8 weeks. Histological assessment of tracheal constructs explanted at week 4 shows that scaffolds can maintain their structural integrity and support the formation of neo-vessels. Furthermore, cell-scaffold constructs gradually form cartilage-like tissues, which mature with time. Collectively, these engineered tracheal scaffolds not only possess appropriate mechanical properties to afford a stabilized structure but also a biomimetic extracellular matrix-like structure to accomplish tissue regeneration, which may have broad implications for tracheal regeneration.
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Conjugate Electrospun 3D Gelatin Nanofiber Sponge for Rapid Hemostasis (Adv. Healthcare Mater. 20/2021). Adv Healthc Mater 2021. [DOI: 10.1002/adhm.202170095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Conjugate Electrospun 3D Gelatin Nanofiber Sponge for Rapid Hemostasis. Adv Healthc Mater 2021; 10:e2100918. [PMID: 34235873 DOI: 10.1002/adhm.202100918] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 06/12/2021] [Indexed: 12/15/2022]
Abstract
Developing an excellent hemostatic material with good biocompatibility and high blood absorption capacity for rapid hemostasis of deep non-compressible hemorrhage remains a significant challenge. Herein, a novel conjugate electrospinning strategy to prepare an ultralight 3D gelatin sponge consisting of continuous interconnected nanofibers. This unique fluffy nanofiber structure endows the sponge with low density, high surface area, compressibility, and ultrastrong liquid absorption capacity. In vitro assessments show the gelatin nanofiber sponge has good cytocompatibility, high cell permeability, and low hemolysis ratio. The rat subcutaneous implantation studies demonstrate good biocompatibility and biodegradability of gelatin nanofiber sponge. Gelatin nanofiber sponge aggregates and activates platelets in large quantities to accelerate the formation of platelet embolism, and simultaneously escalates other extrinsic and intrinsic coagulation pathways, which collectively contribute to its superior hemostatic capacity. In vivo studies on an ear artery injury model and a liver trauma model of rabbits demonstrate that the gelatin nanofiber sponge rapidly induce stable blood clots with least blood loss compared to gelatin nanofiber membrane, medical gauze, and commercial gelatin hemostatic sponge. Hence, the gelatin nanofiber sponge holds great potential as an absorbable hemostatic agent for rapid hemostasis.
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Multifunctional bioactive core-shell electrospun membrane capable to terminate inflammatory cycle and promote angiogenesis in diabetic wound. Bioact Mater 2021; 6:2783-2800. [PMID: 33665509 PMCID: PMC7900605 DOI: 10.1016/j.bioactmat.2021.01.040] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 01/25/2021] [Accepted: 01/31/2021] [Indexed: 12/21/2022] Open
Abstract
Diabetic wound (DW) healing is a major clinical challenge due to multifactorial complications leading to prolonged inflammation. Electrospun nanofibrous (NF) membranes, due to special structural features, are promising biomaterials capable to promote DW healing through the delivery of active agents in a controlled manner. Herein, we report a multifunctional composite NF membrane loaded with ZnO nanoparticles (NP) and oregano essential oil (OEO), employing a new loading strategy, capable to sustainedly co-deliver bioactive agents. Physicochemical characterization revealed the successful fabrication of loaded nanofibers with strong in vitro anti-bacterial and anti-oxidant activities. Furthermore, in vivo wound healing confirmed the potential of bioactive NF membranes in epithelialization and granulation tissue formation. The angiogenesis was greatly prompted by the bioactive NF membranes through expression of vascular endothelial growth factor (VEGF). Moreover, the proposed NF membrane successfully terminated the inflammatory cycle by downregulating the pro-inflammatory cytokines interleukin −6 (IL-6) and matrix metalloproteinases-9 (MMP-9). In vitro and in vivo studies revealed the proposed NF membrane is a promising dressing material for the healing of DW. A modified loading strategy was employed for dual bioactive agents through electrospinning. The nanofibers sustainedly released the two bioactive agents. The fabricated bioactive membranes turned out to be biocompatible, antioxidant and antibacterial. The proposed bioactive membranes have posesses the potential of healing diabetic wounds.
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Flexible and reusable carbon nano-fibre membranes for airborne contaminants capture. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 754:142231. [PMID: 33254856 DOI: 10.1016/j.scitotenv.2020.142231] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/09/2020] [Accepted: 09/03/2020] [Indexed: 06/12/2023]
Abstract
Airborne aerosol pollutants generated from combustion vehicles exhausts, industrial facilities and microorganisms represent serious health challenges. Although membrane separation has emerged as a technique of choice for airborne contaminants removal, allowing for both size exclusion and surface adsorption. Here, electrospun carbon nanofibre mats were formed from poly(acrylonitrile) by systematic stabilization and carbonization processes to generate flexible and self-standing membranes for air filtration. The great mechanical flexibility of the electrospun carbon-nanofibre membranes was achieved through extreme quenching conditions on a carbon fibre processing line, allowing for complete carbonization in just 3 min. The carbonized nanofibre membranes, with fibre diameters in the range of 218 to 565 nm exhibited modulus of elasticity around 277.5 MPa. The samples exhibited air filtration efficiencies in the range of 97.2 to 99.4% for aerosol particle in the size of 300 nm based on face velocity, higher than benchmark commercial glass fibre (GF) air filters. The carbonized electrospun nanofibre membranes also yielded excellent thermal stability withstanding temperatures up to 450 °C, thus supporting the development of autoclavable and recyclable membranes. This significant and scalable strategy provides opportunities to mass-produce reusable air filters suitable for otherwise complex airborne pollutants, including volatile organic carbons and bio-contaminants, such as viruses.
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Exploration of the antibacterial and wound healing potential of a PLGA/silk fibroin based electrospun membrane loaded with zinc oxide nanoparticles. J Mater Chem B 2021; 9:1452-1465. [PMID: 33470267 DOI: 10.1039/d0tb02822c] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Zinc oxide nanoparticles (ZnO NPs) are known for their antibacterial, antioxidant, and anti-inflammatory activities. Moreover, ZnO NPs can stimulate cell migration, re-epithelialization, and angiogenesis. All these attributes are highly relevant to wound healing. Local administration of ZnO NPs to the wound can be achieved through electrospun nanofibers. We hypothesized that the use of poly(lactide-co-glycolic acid) (PLGA)/silk fibroin (SF) nanofiber-based delivery of ZnO would maintain the bioavailability of NPs on the wound area and synchronization with the unique structural features of electrospun nanofibers, could stimulate wound closure, re-epithelialization, collagen deposition, cellular migration, and angiogenesis. In this study, we fabricated PLGA/SF (PS) nanofibrous (NF) membranes with and without ZnO NPs and extensively characterized them for various physicochemical and biological attributes. Scanning electron microscopy (SEM) revealed smooth fibers and ZnO concentration-dependent increase in the fiber diameter. Transmission electron microscopy (TEM) also confirmed the encapsulation of ZnO NPs in the polymer matrix. The successful loading of ZnO was further confirmed by X-ray diffraction. Furthermore, mechanical testing revealed a ZnO concentration-dependent increase in the tensile strength. Moreover, biocompatibility was evaluated through in vitro cell culture. A mild anti-oxidant activity was also noted mainly due to the presence of silk fibroin. In vitro antibacterial tests revealed a ZnO concentration-dependent increase in antibacterial activity and PLGA/SF/3% ZnO (PSZ3) remained completely active against E. coli and S. aureus. More importantly, NF membranes were evaluated for their in vivo wound healing potential. The PSZ3 NF membrane not only facilitated the early wound closure but also remarkably enhanced the quality of wound healing confirmed through histopathological analysis. Re-epithelialization, granulation tissue formation, collagen deposition, and angiogenesis are some of the key parameters significantly boosted by ZnO loaded composite NF membranes. Based on extensive characterization and biological evaluation, the PSZ3 NF membrane has turned out to be a potential candidate for wound healing applications.
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Advanced fabrication for electrospun three-dimensional nanofiber aerogels and scaffolds. Bioact Mater 2020; 5:963-979. [PMID: 32671291 PMCID: PMC7334396 DOI: 10.1016/j.bioactmat.2020.06.023] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/23/2020] [Accepted: 06/24/2020] [Indexed: 12/20/2022] Open
Abstract
Electrospinning is a versatile strategy for creating nanofiber materials with various structures, which has broad application for a myriad of areas ranging from tissue engineering, energy harvesting, filtration and has become one of the most important academic and technical activities in the field of material science in recent years. In addition to playing a significant role in the construction of two-dimensional (2D) nanomaterials, electrospinning holds great promise as a robust method for producing three-dimensional (3D) aerogels and scaffolds. This article reviews and summarizes the recent advanced methods for fabricating electrospun three-dimensional nanofiber aerogels and scaffolds, including gas foaming, direct electrospinning of 3D nanofibrous scaffold, short nanofibers assembling into 3D aerogels/scaffolds, 3D printing, electrospray, origami and cell sheet engineering, centrifugal electrospinning, and other methods. Besides, intriguing formation process, crosslinking pathway, properties, and applications of 3D aerogels and scaffolds are also introduced. Taken together, these aerogels and scaffolds with various excellent features present tremendous potential in various fields.
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Blood Pressure Sensors: Materials, Fabrication Methods, Performance Evaluations and Future Perspectives. SENSORS (BASEL, SWITZERLAND) 2020; 20:E4484. [PMID: 32796604 PMCID: PMC7474433 DOI: 10.3390/s20164484] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Revised: 07/31/2020] [Accepted: 08/04/2020] [Indexed: 12/14/2022]
Abstract
Advancements in materials science and fabrication techniques have contributed to the significant growing attention to a wide variety of sensors for digital healthcare. While the progress in this area is tremendously impressive, few wearable sensors with the capability of real-time blood pressure monitoring are approved for clinical use. One of the key obstacles in the further development of wearable sensors for medical applications is the lack of comprehensive technical evaluation of sensor materials against the expected clinical performance. Here, we present an extensive review and critical analysis of various materials applied in the design and fabrication of wearable sensors. In our unique transdisciplinary approach, we studied the fundamentals of blood pressure and examined its measuring modalities while focusing on their clinical use and sensing principles to identify material functionalities. Then, we carefully reviewed various categories of functional materials utilized in sensor building blocks allowing for comparative analysis of the performance of a wide range of materials throughout the sensor operational-life cycle. Not only this provides essential data to enhance the materials' properties and optimize their performance, but also, it highlights new perspectives and provides suggestions to develop the next generation pressure sensors for clinical use.
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Wrinkled silica doped electrospun nano-fiber membranes with engineered roughness for advanced aerosol air filtration. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2019.01.049] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Electrospun Bilayer Composite Vascular Graft with an Inner Layer Modified by Polyethylene Glycol and Haparin to Regenerate the Blood Vessel. J Biomed Nanotechnol 2019; 15:77-84. [PMID: 30480516 DOI: 10.1166/jbn.2019.2666] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In this study, we prepared a composite vascular graft with two layers. The inner layer, which was comprised of degradable Poly(lactic-co-glycolic acid) (PLGA)/Collagen (PC) nanofibers modified by mesoporous silica nanoparticles (MSN), was grafted with polyethylene glycol (PEG) and heparin to promote cell proliferation and to improve blood compatibility. The outer layer was comprised of polyurethane (PU) nanofibers in order to provide mechanical support. The growth and proliferation of human umbilical vein endothelial cells (HUVECs) in the inner layer was significant, and blood compatibility testing showed that the inner layer had good blood compatibility. The MSN-PEG-Heparin on the fiber surface was observed in vitro during the degradation of the inner layer. After 60 days, the weight of fiber membrane decreased by 92.4%. The inner layer did not cause an inflammatory reaction during the degradation process in vivo and there was uniform cellular growth on the PC/MSN-PEG-Heparin fiber membrane. Composite grafts implanted into the rabbit carotid artery were evaluated for 8 weeks by H&E and immunohistochemical staining, demonstrating that a monolayer of endothelium (CD31-labeled) and smooth muscle (αSMA-labeled) regenerated on the composite graft. Our results demonstrate that the composite graft, with a functional inner layer, has potential to be used for small-caliber blood vessels with long-term patency.
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Electrospun Nanofibers for Tissue Engineering with Drug Loading and Release. Pharmaceutics 2019; 11:E182. [PMID: 30991742 PMCID: PMC6523318 DOI: 10.3390/pharmaceutics11040182] [Citation(s) in RCA: 95] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/03/2019] [Accepted: 03/29/2019] [Indexed: 12/20/2022] Open
Abstract
Electrospinning technologies have been applied in the field of tissue engineering as materials, with nanoscale-structures and high porosity, can be easily prepared via this method to bio-mimic the natural extracellular matrix (ECM). Tissue engineering aims to fabricate functional biomaterials for the repairment and regeneration of defective tissue. In addition to the structural simulation for accelerating the repair process and achieving a high-quality regeneration, the combination of biomaterials and bioactive molecules is required for an ideal tissue-engineering scaffold. Due to the diversity in materials and method selection for electrospinning, a great flexibility in drug delivery systems can be achieved. Various drugs including antibiotic agents, vitamins, peptides, and proteins can be incorporated into electrospun scaffolds using different electrospinning techniques and drug-loading methods. This is a review of recent research on electrospun nanofibrous scaffolds for tissue-engineering applications, the development of preparation methods, and the delivery of various bioactive molecules. These studies are based on the fabrication of electrospun biomaterials for the repair of blood vessels, nerve tissues, cartilage, bone defects, and the treatment of aneurysms and skin wounds, as well as their applications related to oral mucosa and dental fields. In these studies, due to the optimal selection of drugs and loading methods based on electrospinning, in vitro and in vivo experiments demonstrated that these scaffolds exhibited desirable effects for the repair and treatment of damaged tissue and, thus, have excellent potential for clinical application.
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One-pot synthesis of catalytic molybdenum based nanocomposite nano-fiber membranes for aerosol air remediation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2019; 647:725-733. [PMID: 30092529 DOI: 10.1016/j.scitotenv.2018.08.050] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Revised: 08/03/2018] [Accepted: 08/04/2018] [Indexed: 05/29/2023]
Abstract
The development of fibrous air filters exhibiting high air filtration efficiency, low energy consumption, and self-cleaning properties is a critical challenge to generate the next generation of resilient air filtration systems. Nano-fibrous mats typically exhibit higher particle capture efficiency but may also lead to higher airflow resistance compared to macro-fibrous materials due to their tighter structure. In this paper, novel catalytic membranes mats were fabricated through a one-pot synthesis from ammonium tetrathiomolybdate (ATTM) doped poly(acrylonitrile) (PAN) nanofibers for sub-micron diameter aerosol particle removal. The presence of ATTM as a dopant in conjunction with a PAN polymeric matrix was found to not only enhance the air filtration performance by increasing aerosol particle removal down to 300 nm, but also increase the photocatalytic properties of the PAN material. The enhanced separation properties compared to bare polymeric PAN nanofibrous membranes were attributed to surface nanotexturation of the fibers, leading to protrusions and pores across the nano-fiber structures, thus leading to more permeable and lightweight membranes with higher particle capture capacities. The samples were benchmarked against commercial glass fiber air filters and found to offer higher filtration efficiency, lower pressure drop, and higher quality factor than the commercial filters. Specifically, the quality factors of the catalytic nano-fiber membranes were found to be up to four times higher than that of the benchmarked commercial air filters for PM2.5 particles, while two times higher for 300 nm sized contaminants. The presence of the ATTM across the PAN matrix was also found to enhance the photocatalytic activity of the membranes by up to 130% compared to the bare PAN reference nanofibers. This novel strategy opens avenues to engineering advanced multifunctional catalytic membranes, to capture toxic particulate matter from air while offering self-cleaning properties when exposed to sunlight.
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Three-dimensional electrospun nanofibrous scaffolds displaying bone morphogenetic protein-2-derived peptides for the promotion of osteogenic differentiation of stem cells and bone regeneration. J Colloid Interface Sci 2019; 534:625-636. [DOI: 10.1016/j.jcis.2018.09.071] [Citation(s) in RCA: 76] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 09/19/2018] [Accepted: 09/20/2018] [Indexed: 12/16/2022]
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Pore engineering towards highly efficient electrospun nanofibrous membranes for aerosol particle removal. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 625:706-715. [PMID: 29306158 DOI: 10.1016/j.scitotenv.2017.12.342] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 12/21/2017] [Accepted: 12/29/2017] [Indexed: 06/07/2023]
Abstract
Electrospun nanofibrous membranes were engineered for aerosol particle removal by controlling the fiber density and alignment across electrospun mats. Electrospun nanofiber membranes were deposited on both, rotatory drum and stationary collectors, to investigate the effect of fiber alignment on filtration performance. Poly(acrylonitrile)/dimethyl formamide (PAN/DMF) solutions were used to produce membranes for applications in air purification. The air filtration performance of as-produced and hot-compacted membranes were systematically evaluated with regard to penetration, pressure drop, and quality factor when subjected to potassium chloride (KCl) aerosol particles in the size-range of 300nm to 12μm. The membranes offered air filtration efficiencies in the range of 77.7% to 99.616% and quality factors between 0.0026 and 0.0204 (1/Pa). The samples were benchmarked against commercial filters and were found to exhibit similar quality factors but higher air filtration efficiencies. These results were correlated to differences in pore morphologies and fiber orientation distributions generated from the different processing techniques, which revealed that the alteration of the fiber density is an effective method for enhancing air filtration performance.
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Synthesis and characterization of incorporating mussel mimetic moieties into photoactive hydrogel adhesive. Colloids Surf B Biointerfaces 2018; 161:94-102. [DOI: 10.1016/j.colsurfb.2017.10.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/08/2017] [Accepted: 10/13/2017] [Indexed: 01/28/2023]
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Fabrication and characterization of TGF-β1-loaded electrospun poly (lactic-co-glycolic acid) core-sheath sutures. Colloids Surf B Biointerfaces 2018; 161:331-338. [DOI: 10.1016/j.colsurfb.2017.10.066] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2017] [Revised: 10/25/2017] [Accepted: 10/26/2017] [Indexed: 02/06/2023]
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Development of Dynamic Liquid and Conjugated Electrospun Poly(L-lactide-co-caprolactone)/Collagen Nanoyarns for Regulating Vascular Smooth Muscle Cells Growth. J Biomed Nanotechnol 2017; 13:303-12. [DOI: 10.1166/jbn.2017.2352] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Application of a bilayer tubular scaffold based on electrospun poly(l-lactide-co-caprolactone)/collagen fibers and yarns for tracheal tissue engineering. J Mater Chem B 2017; 5:139-150. [DOI: 10.1039/c6tb02484j] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An electrospun bilayer tubular scaffold based on collagen/P(LLA–CL) was prepared and preprocessing with autologous tracheal cells and vascularization was done for the purpose of tracheal tissue engineering.
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Laminin-coated nerve guidance conduits based on poly(l-lactide-co-glycolide) fibers and yarns for promoting Schwann cells’ proliferation and migration. J Mater Chem B 2017; 5:3186-3194. [DOI: 10.1039/c6tb03330j] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
A laminin-coated and yarn-encapsulated PLGA nerve guidance conduit for Schwann cells’ proliferation and migration.
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Superabsorbent 3D Scaffold Based on Electrospun Nanofibers for Cartilage Tissue Engineering. ACS APPLIED MATERIALS & INTERFACES 2016; 8:24415-24425. [PMID: 27559926 DOI: 10.1021/acsami.6b06825] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Electrospun nanofibers have been used for various biomedical applications. However, electrospinning commonly produces two-dimensional (2D) membranes, which limits the application of nanofibers for the 3D tissue engineering scaffold. In the present study, a porous 3D scaffold (3DS-1) based on electrospun gelatin/PLA nanofibers has been prepared for cartilage tissue regeneration. To further improve the repairing effect of cartilage, a modified scaffold (3DS-2) cross-linked with hyaluronic acid (HA) was also successfully fabricated. The nanofibrous structure, water absorption, and compressive mechanical properties of 3D scaffold were studied. Chondrocytes were cultured on 3D scaffold, and their viability and morphology were examined. 3D scaffolds were also subjected to an in vivo cartilage regeneration study on rabbits using an articular cartilage injury model. The results indicated that 3DS-1 and 3DS-2 exhibited superabsorbent property and excellent cytocompatibility. Both these scaffolds present elastic property in the wet state. An in vivo study showed that 3DS-2 could enhance the repair of cartilage. The present 3D nanofibrous scaffold (3DS-2) would be promising for cartilage tissue engineering application.
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Superelastic, superabsorbent and 3D nanofiber-assembled scaffold for tissue engineering. Colloids Surf B Biointerfaces 2016; 142:165-172. [PMID: 26954082 DOI: 10.1016/j.colsurfb.2016.02.050] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 02/20/2016] [Accepted: 02/23/2016] [Indexed: 10/22/2022]
Abstract
Fabrication of 3D scaffold to mimic the nanofibrous structure of the nature extracellular matrix (ECM) with appropriate mechanical properties and excellent biocompatibility, remain an important technical challenge in tissue engineering. The present study reports the strategy to fabricate a 3D nanofibrous scaffold with similar structure to collagen in ECM by combining electrospinning and freeze-drying technique. With the technique reported here, a nanofibrous structure scaffold with hydrophilic and superabsorbent properties can be readily prepared by Gelatin and Polylactic acid (PLA). In wet state the scaffold also shows a super-elastic property, which could bear a compressive strain as high as 80% and recovers its original shape afterwards. Moreover, after 6 days of culture, L-929 cells grow, proliferate and infiltrated into the scaffold. The results suggest that this 3D nanofibrous scaffold would be promising for varied field of tissue engineering application.
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Modified alginate and gelatin cross-linked hydrogels for soft tissue adhesive. ARTIFICIAL CELLS NANOMEDICINE AND BIOTECHNOLOGY 2016; 45:76-83. [DOI: 10.3109/21691401.2015.1129622] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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Preparation and characterization of electrospun in-situ cross-linked gelatin-graphite oxide nanofibers. JOURNAL OF BIOMATERIALS SCIENCE-POLYMER EDITION 2016; 27:385-402. [PMID: 26733331 DOI: 10.1080/09205063.2015.1133156] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Electrospun gelatin(Gel) nanofibers scaffold has such defects as poor mechanical property and quick degradation due to high solubility. In this study, the in situ cross-linked electrospinning technique was used for the production of gelatin nanofibers. Deionized water was chosen as the spinning solvent and graphite oxide (GO) was chosen as the enhancer. The morphological structure, porosity, thermal property, moisture absorption, and moisture retention performance, hydrolysis resistance, mechanical property, and biocompatibility of the produced nanofibers were investigated. Compared with in situ cross-linked gelatin nanofibers scaffold, in situ cross-linked Gel-GO nanofibers scaffold has the following features: (1) the hydrophilicity, moisture absorption, and moisture retention performance slightly reduce, while the hydrolysis resistance is improved; (2) the breaking strength, breaking elongation, and Young's modulus are significantly improved; (3) the porosity slightly reduces while the biocompatibility considerably increases. The in situ cross-linked Gel-GO nanofibers scaffold is likely to be applied in such fields as drug delivery and scaffold for skin tissue engineering.
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An in situ forming tissue adhesive based on poly(ethylene glycol)-dimethacrylate and thiolated chitosan through the Michael reaction. J Mater Chem B 2016; 4:5585-5592. [DOI: 10.1039/c6tb01475e] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A novel tissue adhesive composed of CSS and PEGDMA based on the Michael addition reaction.
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From mechanical stimulation to biological pathways in the regulation of stem cell fate. Cell Biochem Funct 2014; 32:309-25. [PMID: 24574137 DOI: 10.1002/cbf.3027] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 11/28/2013] [Accepted: 01/07/2014] [Indexed: 12/15/2022]
Abstract
Mechanical stimuli are important in directing the fate of stem cells; the effects of mechanical stimuli reported in recent research are reviewed here. Stem cells normally undergo two fundamental processes: proliferation, in which their numbers multiply, and differentiation, in which they transform into the specialized cells needed by the adult organism. Mechanical stimuli are well known to affect both processes of proliferation and differentiation, although the complete pathways relating specific mechanical stimuli to stem cell fate remain to be elucidated. We identified two broad classes of research findings and organized them according to the type of mechanical stress (compressive, tensile or shear) of the stimulus. Firstly, mechanical stress of any type activates stretch-activated channels (SACs) on the cell membrane. Activation of SACs leads to cytoskeletal remodelling and to the expression of genes that regulate the basic growth, survival or apoptosis of the cells and thus regulates proliferation. Secondly, mechanical stress on cells that are physically attached to an extracellular matrix (ECM) initiates remodelling of cell membrane structures called integrins. This second process is highly dependent on the type of mechanical stress applied and result into various biological responses. A further process, the Wnt pathway, is also implicated: crosstalk between the integrin and Wnt pathways regulates the switch from proliferation to differentiation and finally regulates the type of differentiation. Therefore, the stem cell differentiation process involves different signalling molecules and their pathways and most likely depends upon the applied mechanical stimulation.
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Electrospun collagen-chitosan-TPU nanofibrous scaffolds for tissue engineered tubular grafts. Colloids Surf B Biointerfaces 2010; 82:307-15. [PMID: 20888196 DOI: 10.1016/j.colsurfb.2010.09.002] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Revised: 08/26/2010] [Accepted: 09/01/2010] [Indexed: 11/16/2022]
Abstract
The objective of this study is to design a novel kind of scaffolds for blood vessel and nerve repairs. Random and aligned nanofibrous scaffolds based on collagen-chitosan-thermoplastic polyurethane (TPU) blends were electrospun to mimic the componential and structural aspects of the native extracellular matrix, while an optimal proportion was found to keep the balance between biocompatibility and mechanical strength. The scaffolds were crosslinked by glutaraldehyde (GTA) vapor to prevent them from being dissolved in the culture medium. Fiber morphology was characterized using scanning electron microscopy (SEM) and atomic-force microscopy (AFM). Fourier transform infrared spectroscopy (FTIR) showed that the three-material system exhibits no significant differences before and after crosslinking, whereas pore size of crosslinked scaffolds decreased drastically. The mechanical properties of the scaffolds were found to be flexible with a high tensile strength. Cell viability studies with endothelial cells and Schwann cells demonstrated that the blended nanofibrous scaffolds formed by electrospinning process had good biocompatibility and aligned fibers could regulate cell morphology by inducing cell orientation. Vascular grafts and nerve conduits were electrospun or sutured based on the nanofibrous scaffolds and the results indicated that collagen-chitosan-TPU blended nanofibrous scaffolds might be a potential candidate for vascular repair and nerve regeneration.
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Numerical simulation of the turbulent flow field distal to an aortic heart valve. FRONTIERS OF MEDICAL AND BIOLOGICAL ENGINEERING : THE INTERNATIONAL JOURNAL OF THE JAPAN SOCIETY OF MEDICAL ELECTRONICS AND BIOLOGICAL ENGINEERING 2002; 11:1-11. [PMID: 11556500 DOI: 10.1163/156855701750383150] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A numerical technique is described which simulates the turbulent flow through a aortic Jellyfish valve, for two volumetric flow rates of 15 and 26 l/min representing peak systole flow. The steady incompressible Navier-Stokes equations written in three-dimensional (3-D) format are solved iteratively using a computational fluid dynamics code (Bio-FL). The numerical results show that the flow at the edge of the membrane of the valve splits into two nearly symmetrical jets with similar phenomenological features. Moreover, the 3-D flow simulations indicate the existence of two vortices in the immediate vicinity of the valve ring. Although these vortices are attenuated rapidly downstream by diffusion, they can have an adverse effect on erythrocytes and active platelets. It is also shown that elevated shear stresses occur in the vicinity of the upstream surface of the open occluder. In general. the numerical predictions compare well with the experimental measurements made at various locations downstream of the valve. The locations and the values of maximum velocity and shear stress, as well as width and length of re-circulation regions, are correctly predicted.
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