Fabrication and characterization of PCL/gelatin/chitosan ternary nanofibrous composite scaffold for tissue engineering applications

In the present study, we have fabricated a ternary composite nanofibrous scaffold from PCL/gelatin/chitosan, by electrospinning technique, using a solvent system—chloroform/methanol for polycaprolactone (PCL) and acetic acid for gelatin and chitosan, for tissue engineering applications. Field emission scanning electron microscopy (FE-SEM) was used to investigate the fiber morphology of the scaffold and it was found that the fiber morphology was influenced by the concentrations of PCL, gelatin, and chitosan in polymer solution during electrospinning. X-ray diffraction, Fourier transform infrared, and thermogravimetric (TG) analysis results showed some interactions among the molecules of PCL, gelatin, and chitosan within the scaffold. In-vitro cell culture studies were done by seeding L929 mouse fibroblasts on fabricated composite scaffold, which confirmed the cell viability, high cell proliferation rate, and cell adhesion on composite scaffold as indicated by MTT assay, DNA quantification, and FE-SEM analysis of cell-scaffold construct. Thus, the ternary composite scaffold made from the combination of PCL (synthetic polymer), gelatin, and chitosan (natural polymer) may find potential application in tissue engineering.     

Fabrication and characterization of gold nanoparticle-doped electrospun PCL/chitosan nanofibrous scaffolds for nerve tissue engineering

In the field of nerve tissue engineering, nanofibrous scaffolds could be a promising candidate when they are incorporated with electrical cues. Unique physico-chemical properties of gold nanoparticles (AuNPs) make them an appropriate component for increasing the conductivity of scaffolds to enhance the electrical signal transfer between neural cells. The aim of this study was fabrication of AuNPs-doped nanofibrous scaffolds for peripheral nerve tissue engineering. Polycaprolactone (PCL)/chitosan mixtures with different concentrations of chitosan (0.5, 1 and 1.5) were electrospun to obtain nanofibrous scaffolds. AuNPs were synthesized by the reduction of HAuCl₄ using chitosan as a reducing/stabilizing agent. A uniform distribution of AuNPs with spherical shape was achieved throughout the PCL/chitosan matrix. The UV–Vis spectrum revealed that the amount of gold ions absorbed by nanofibrous scaffolds is in direct relationship with their chitosan content. Evaluation of electrical property showed that inclusion of AuNPs significantly enhanced the conductivity of scaffolds. Finally, after 5 days of culture, biological response of Schwann cells on the AuNPs-doped scaffolds was superior to that on as-prepared scaffolds in terms of improved cell attachment and higher proliferation. It can be concluded that the prepared AuNPs-doped scaffolds can be used to promote peripheral nerve regeneration.

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磷酸钙骨水泥/明胶复合组织工程支架材料的制备及其结构与性能

磷酸钙骨水泥组织工程支架材料具有良好的生物相容性和骨传导性,是一种良好的骨组织工程支架材料,但是这种材料存在力学性能差的缺点,限制了它的应用.本文采用生物相容性良好的可降解明胶材料与磷酸钙骨水泥支架进行复合,制备出的明胶/磷酸钙骨水泥复合支架材料,其压缩强度可达3.7MPa,比复合前磷酸钙支架材料的强度提高了37倍,而且材料具有良好的柔韧性,适合用作为非承重部位骨组织缺损修复用组织工程支架材料.     

Fabrication and in vitro evaluation of a sponge-like bioactive-glass/gelatin composite scaffold for bone tissue engineering

In this work a bioactive composite scaffold, comprised of bioactive-glass and gelatin, is introduced. Through direct foaming a sponge-like composite of a sol–gel derived bioactive-glass (70S30C; 70% SiO₂, 30% CaO) and porcine gelatin was developed for use as a biodegradable scaffold for bone tissue engineering. The composite was developed to provide a suitable alternative to synthetic polymer based scaffolds, allowing directed regeneration of bone tissue. The fabricated scaffold was characterised through X-ray microtomography, scanning electron and light microscopy demonstrating a three dimensionally porous and interconnected structure, with an average pore size (170 μm) suitable for successful cell proliferation and tissue ingrowth. Acellular bioactivity was assessed through apatite formation during submersion in simulated body fluid (SBF) whereby the rate and onset of apatite nucleation was found to be comparable to that of bioactive-glass. Modification of dehydrothermal treatment parameters induced varying degrees of crosslinking, allowing the degradation of the composite to be tailored to suit specific applications and establishing its potential for a wide range of applications. Use of genipin to supplement crosslinking by dehydrothermal treatment provided further means of modifying degradability. Biocompatibility of the composite was qualified through successful cultures of human dental pulp stem cells (HDPSCs) on samples of the composite scaffold. Osteogenic differentiation of HDPSCs and extracellular matrix deposition were confirmed through positive alkaline phosphatase staining and immunohistochemistry.     

Fabrication and characterization of scaffold from cadaver goat-lung tissue for skin tissue engineering applications

The present study aims to fabricate scaffold from cadaver goat-lung tissue and evaluate it for skin tissue engineering applications. Decellularized goat-lung scaffold was fabricated by removing cells from cadaver goat-lung tissue enzymatically, to have cell-free 3D-architecture of natural extracellular matrix. DNA quantification assay and Hematoxylin and eosin staining confirmed the absence of cellular material in the decellularized lung-tissue. SEM analysis of decellularized scaffold shows the intrinsic porous structure of lung tissue with well-preserved pore-to-pore interconnectivity. FTIR analysis confirmed non-denaturation and well maintainance of collagenous protein structure of decellularized scaffold. MTT assay, SEM analysis and H&E staining of human skin-derived Mesenchymal Stem cell, seeded over the decellularized scaffold, confirms stem cell attachment, viability, biocompatibility and proliferation over the decellularized scaffold. Expression of Keratin18 gene, along with CD105, CD73 and CD44, by human skin-derived Mesenchymal Stem cells over decellularized scaffold signifies that the cells are viable, proliferating and migrating, and have maintained their critical cellular functions in the presence of scaffold. Thus, overall study proves the applicability of the goat-lung tissue derived decellularized scaffold for skin tissue engineering applications.     

Multifunctional nanofibrous scaffold for tissue engineering

In tissue engineering, scaffolds with multiscale functionality, especially with the ability to release locally multiple or specific bioactive molecules to targeted cell types, are highly desired in regulating appropriate cell phenotypes. In this study, poly (epsilon-caprolactone) (PCL) solutions (8% w/v) containing different amounts of bovine serum albumin (BSA) with or without collagen were electrospun into nanofibres. As verified by protein release assay and fluorescent labelling, BSA and collagen were successfully incorporated into electrospun nanofibres. The biological activity of functionalised fibres was proven in the cell culture experiments using human dermal fibroblasts. By controlling the sequential deposition and fibre alignment, 3D scaffolds with spatial distribution of collagen or BSA were assembled using fluorescently labelled nanofibres. Human dermal fibroblasts showed preferential adhesion to PCL nanofibres containing collagen than PCL alone. Taken together, multiscale scaffolds with diverse functionality and tunable distribution of biomolecules across the nanofibrous scaffold can be fabricated using electrospun nanofibres.     

Fabrication of surface modified antibacterial Ti6Al4V alloy powder reinforced gelatin/chitosan composite scaffold for tissue engineering applications

The present work attempted to modify Ti6Al4V (Ti64) alloy powder to induce biocompatibility and antimicrobial properties by incorporating Ca²⁺ and Ag⁺ ions, respectively using a simple chemical treatment followed by ion exchange method. Thus functionally modified Ti64 alloy powders characterized using FE-SEM and Raman spectroscopic techniques indicate the formation of fine porous network structure along with the evolution of different phases of titania upon heat treatment in presence of Ca²⁺ and Ag⁺ ions. The incorporation of Ca²⁺ ions and transformation of Ag⁺ ions into AgNPs and their decoration on the nano porous network structure have been confirmed by the HR-TEM and EDX results. Optimized concentration of AgNPs decorated Ti64 alloy powder not only found to induce antimicrobial activity against both Gram-positive S. aureus and Gram-negative E. coli bacteria and also compatible with MG-63 cell lines. Surface functionalized Ti64 alloy powder was subsequently used as reinforcement for the fabrication of gelatin - chitosan composite scaffolds using the lyophilization technique. Thus fabricated composite scaffold was analyzed for its pore morphology and pore distribution along with its in-vitro cell toxicity towards MG-63 cell lines using MTT assay. Taken together, surface modified Ti64 alloy powder reinforced gelatin-chitosan composite scaffold with biocompatible and antimicrobial properties is expected to be suitable for tissue engineering applications.     

Fabrication and properties of porous scaffold of zein/PCL biocomposite for bone tissue engineering

The aim of this study was to fabricate porous scaffolds of zein/poly(ε-caprolactone) (PCL) biocomposite by solvent casting–particulate leaching method using sodium chloride particles as the porogen. Porous biocomposite scaffolds with porosity around 70% and well-interconnected network were obtained. The incorporation of zein into PCL led to the improvement of hydrophilicity as indicated by the results of water contact angle measurement. After immersion in phosphate buffered saline (PBS) in vitro for 28 days, it was observed that the degradation rate of the zein/PCL biocomposite scaffold was faster than the PCL scaffold and that the rate could be tailored by adjusting the amount of zein in the composite. The results demonstrate the potential of the zein/PCL biocomposite scaffolds to be used in tissue engineering strategies to regenerate bone defects.     

Bio-functionalized PCL nanofibrous scaffolds for nerve tissue engineering

Surface properties of scaffolds such as hydrophilicity and the presence of functional groups on the surface of scaffolds play a key role in cell adhesion, proliferation and migration. Different modification methods for hydrophilicity improvement and introduction of functional groups on the surface of scaffolds have been carried out on synthetic biodegradable polymers, for tissue engineering applications. In this study, alkaline hydrolysis of poly (ε-caprolactone) (PCL) nanofibrous scaffolds was carried out for different time periods (1 h, 4 h and 12 h) to increase the hydrophilicity of the scaffolds. The formation of reactive groups resulting from alkaline hydrolysis provides opportunities for further surface functionalization of PCL nanofibrous scaffolds. Matrigel was attached covalently on the surface of an optimized 4 h hydrolyzed PCL nanofibrous scaffolds and additionally the fabrication of blended PCL/matrigel nanofibrous scaffolds was carried out. Chemical and mechanical characterization of nanofibrous scaffolds were evaluated using attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, contact angle, scanning electron microscopy (SEM) and tensile measurement. In vitro cell adhesion and proliferation study was carried out after seeding nerve precursor cells (NPCs) on different scaffolds. Results of cell proliferation assay and SEM studies showed that the covalently functionalized PCL/matrigel nanofibrous scaffolds promote the proliferation and neurite outgrowth of NPCs compared to PCL and hydrolyzed PCL nanofibrous scaffolds, providing suitable substrates for nerve tissue engineering.     

In vitro evaluation of electrospun PCL/nanoclay composite scaffold for bone tissue engineering

Polycaprolactone (PCL) is a widely accepted synthetic biodegradable polymer for tissue engineering, however its use in hard tissue engineering is limited because of its inadequate mechanical strength and low bioactivity. In this study, we used halloysite nanoclay (NC) as an inorganic filler material to prepare PCL/NC fibrous scaffolds via electrospinning technique after intercalating NC within PCL by solution intercalation method. The obtained nanofibrous mat was found to be mechanically superior to PCL fibrous scaffolds. These scaffolds allowed greater protein adsorption and enhanced mineralization when incubated in simulated body fluid. Moreover, our results indicated that human mesenchymal stem cells (hMSCs) seeded on these scaffolds were viable and could proliferate faster than in PCL scaffolds as confirmed by fluorescence and scanning electron microscopic observations. Further, osteogenic differentiation of hMSCs on nanoclay embedded scaffolds was demonstrated by an increase in alkaline phosphatase activity when compared to PCL scaffold without nanoclay. All of these results suggest the potential of PCL/NC scaffolds for bone tissue engineering.     

聚己内酯/羟基磷灰石晶须复合多孔支架的研究

采用溶液浇铸法,以二氯甲烷作为溶剂,制备了聚己内酯/羟基磷灰石晶须(PCL/HAw)复合多孔支架,并进行了正交试验,综合分析了不同配方量的PCL和HAw对材料机械性能的影响。结果表明,可通过控制PCL的量来控制支架的力学性能,通过加入HAw提高支架的亲水性能,支架的接触角实验显示其接触角为81°;PCL的结晶度会随着HAw含量的增加而增强,复合多孔支架的抗拉强度为1.43M~9.21MPa,并在PCL与HAw的质量比为100∶3时达到最大;细胞毒性实验显示,PCL/HAw复合多孔支架细胞毒性为0,满足生物材料使用要求。     

Fabrication of novel PLA/CDHA bionanocomposite fibers for tissue engineering applications via electrospinning

The main theme here is to fabricate PLA (poly lactic-acid)/CDHA (carbonated calcium deficient hydroxyapatite) bionanocomposites, where both the constituents are biocompatible and biodegradable with one dimension in nanometer scale. Such materials are important in tissue engineering applications. The bionanocomposite fibers were fabricated via electrospinning. There are two important signatures of this paper. First, CDHA, rather than HA, is added to PLA as the second phase. As opposed to HA, CDHA mimics the bone mineral composition better and is biodegradable. Therefore, PLA/CDHA fibers should have better biodegradability while maintaining a physiological pH during degradation. To the best of our knowledge, this is the first attempt of electrospinning of such a composite. Second, the CDHA nanoparticles were synthesized using the benign low temperature biomimetic technique, the only route available for the retention of carbonate ions in the HA lattice. The structural properties, degradation behavior, bioactivity, cell adhesion, and growth capability of as-fabricated PLA/CDHA bionanocomposites were investigated. The results show that the incorporation of CDHA decreased PLA fiber diameters, accelerated PLA degradation, buffered pH decrease caused by PLA degradation, improved the bioactivity and biocompatibility of the scaffold. These results prove that PLA/CDHA bionanocomposites have the potential in tissue regeneration applications.     

Fabrication and characterization of a biphasic scaffold for osteochondral tissue engineering

A biphasic scaffold with a stratified structure for osteochondral tissue engineering was developed. The chondral phase was a collagen-chitosan composite. The osseous phase was a composite of bioactive glass and collagen. Collagen integrated in the two respective phases was connected by cross-linking agents. Both layers of the scaffold showed interconnected porous structures. After being immersed into stimulated body fluid, precipitation of spherulitic grains could be found on the surface of the osseous phase and this precipitation was proved to be hydroxyapatite by X-ray diffraction and Fourier transform infrared spectroscopy. Inversion, fluorescence and scanning electron microscopy further confirmed that bone marrow stromal cells could anchor on this scaffold with healthy spreading. As the consequence, this biphasic scaffold may have significant potential as an alternative for osteochondral tissue engineering.     

水溶液电纺制备葡萄籽多酚/明胶复合纤维

以水为溶剂,设计玻璃保温装置,采用静电纺丝技术制备了葡萄籽多酚/明胶复合纤维,系统探讨了浓度、温度、电压、流速等工艺条件以及葡萄籽多酚含量对葡萄籽多酚/明胶复合纤维形貌的影响.结果表明:当明胶浓度为24wt%时,随着温度和电压的增大,纤维平均直径先减小后增大,随葡萄籽多酚含量增大,纤维平均直径增大.通过加入适量葡萄籽多酚,可将纺丝速度从0.25 mL/h提高到0.90 mL/h,显著提高了工作效率;当葡萄籽多酚与明胶的质量比≥1:30时,纤维表面出现串珠;当葡萄籽多酚与明胶的质量比≥1:20时,可纺性变差.在明胶浓度为24wt%,葡萄籽多酚与明胶质量比为1:50,控制温度55 ℃,电压20 kV,接收距离12 cm,速率0.90 mL/h的条件下,制备了纤维直径分布集中,平均直径为515 nm的葡萄籽多酚/明胶复合纤维.明胶溶液中加入适量葡萄籽多酚不仅大大提高了纺丝效率,同时由于其良好的抗菌活性和对明胶的交联作用,使复合纤维膜可广泛应用于生物医药领域,特别是创伤敷料方面.     

Fabrication and characterization of biodegradable nanofibrous mats by mix and coaxial electrospinning

The aim of this study is to investigate an innovative tissue engineering scaffold with a controllable drug-releasing capability. The hypothesis is that the nanofibers fabricated by coaxial electrospinning could encapsulate and release sustainedly Tetracycline Hydrochloride (TCH). To testify the hypothesis, nanofibers were prepared by coaxial electrospinning from Poly(l-lactid-co-ε-caprolactone) [PLLACL]/2,2,2-Frifluoroethanol (TFE) solutions (as the shell solutions) and TCH/TFE solutions (as the core solutions). In addition, nanofibers of PLLACL-blend-TCH were also prepared as the control by mix electrospinning. The relationship between fibers morphologies and processed conditions in electrospinning were investigated. TCH release behaviors from the nanofibrous mats were studied. The antibacterial properties of aforementioned nanofibers were detected by the Escherichia coli growth-inhibiting tests. The results indicated that the nanofibers prepared by coaxial-electrospinning had the desired and controllable TCH encapsulation/release profile; thus, it could be utilized as both a drug encapsulation/release vehicle and a tissue engineering scaffold.     

Fabrication of a composite vascular scaffold using electrospinning technology

Intermolecular forces and morphology demonstrated that there was an excellent compatibility between silk fibroin and gelatin. The silk fibroin/gelatin composite vascular scaffold (inner diameter 4.5 mm) was prepared successfully by electrospinning. The scaffold was treated with ethanol to enhance the water-resistant ability and biomechanical properties. After ethanol treatment, the scaffold could hardly dissolve in the water, and FTIR showed that the conformation of the treated silk fibroin/gelatin composite vascular scaffold was mainly β-sheets. The electrospun silk fibroin/gelatin vascular scaffold possessed outstanding biomechanical properties. In vitro cell culture and in vivo subcutaneous implantation demonstrated that the electrospun silk fibroin/gelatin vascular scaffold had an appropriate biocompatibility. The results indicated that the electrospun silk fibroin/gelatin composite vascular scaffold could be considered as an ideal candidate for tissue-engineered blood vessel.     

Poly(lactide-co-glycolide)/hydroxyapatite nanofibrous scaffolds fabricated by electrospinning for bone tissue engineering

Poly(lactide-co-glycolide) (PLGA) nanofibrous composite scaffolds having nano-hydroxyapatite particles (HAp) in the fibers were prepared by electrospinning of PLGA and HAp with an average diameter of 266.6 ± 7.3 nm. Microscopy and spectroscopy characterizations confirmed integration of the crystalline HAp in the scaffolds. Agglomerates gradually appeared and increased on the fiber surface along with increase of the HAp concentration. In vitro mineralization in a 5 × simulated body fluid (SBF) revealed that the PLGA/HAp nanofibrous scaffolds had a stronger biomineralization ability than the control PLGA scaffolds. Biological performance of the nanofibrous scaffolds of the control PLGA and PLGA with 5 wt% HAp (PLGA/5HAp) was assessed by in vitro culture of neonatal mouse calvaria-derived MC3T3-E1 osteoblasts. Both types of the scaffolds could support cell proliferation and showed sharp increase of viability until 7 days, but the cells cultured on the PLGA/5HAp nanofibers showed a more spreading morphology. Despite the similar level of the cell viability and cell number at each time interval, the alkaline phosphatase secretion was significantly enhanced on the PLGA/5HAp scaffolds, indicating the higher bioactivity of the as-prepared nano-HAp and the success of the present method for preparing biomimetic scaffold for bone regeneration.     

Novel forsterite/polycaprolactone nanocomposite scaffold for tissue engineering applications

Novel highly porous nanocomposite scaffolds consisting of polycaprolactone (PCL) and forsterite nanopowder were prepared by a solvent-casting/particle-leaching method. In addition, the effects of forsterite nanopowder contents on the structure of the scaffolds were investigated to provide an appropriate composite for bone regenerative medicine. Results showed that the scaffolds exhibited high porosity (up to 92%) with open pores of 100-300 μm average diameters. This porosity increased with decreasing forsterite nanopowder content. In addition, the pore walls contained numerous micropores. Microstructure studies showed that the pores were well distributed throughout the structures. Furthermore, the bioactive forsterite nanoparticles were homogenously distributed within the PCL matrix of the scaffolds, which contained up to 30 wt.% forsterite nanopowder. This porous structure with micropores provides the properties required for bone tissue engineering applications.     

Fabrication and characterization of curcumin-loaded silk fibroin/P（LLA-CL） nanofibrous scaffold

Curcumin exhibited excellent properties including antioxidant, anti- inflammatory, antiviral, antibacterial, antifungal, anticancer, and anticoagulant activities. In this study, curcumin was incorporated into silk fibroin （SF）/poly（L-lactic acid-co-e- caprolactone） （P（LLA-CL）） nanofibrous scaffolds via electrospinning, and changes brought about by raising the curcumin content were observed： SEM images showed that the average nanofibrous diameter decreased at the beginning and then increased, and the nanofibers became uniform; FTIR showed that the conformation of SF transforming from random coil form to β-sheet structure had not been induced, while SF conformation converted to β-sheet after being treated with 75% ethanol vapor; XRD results confirmed that the crystal structure of （P（LLA-CL）） had been destroyed; The mechanical test illustrated that nanofibrous scaffolds still maintained good mechanical properties. Further, curcumin-loaded nanofibrous scaffolds were evaluated for drug release, antioxidant and antimicrobial activities in vitro. The results showed that curcumin presented a sustained release behavior from nanofibrous scaffolds and maintained its free radical scavenging ability, and such scaffolds could effectively inhibit S. aureus growth （〉 95%）. Thus, curcumin-loaded SF/P（LLA-CL） nanofibrous scaffolds might be potential candidates for wound dressing and tissue engineering scaffolds.