Fabrication of althea officinalis loaded electrospun nanofibrous scaffold for potential application of skin tissue engineering

The Althea Officinalis (AO) extract is well known as a traditional herbal drug for its wound healing ability owing to the anti-inflammatory and antimicrobial properties. Furthermore, its mucilaginous properties provide moisturizing and nutritional effects on skin cell proliferation. Therefore, AO extract can be applied in the temporary skin substitute for the ability to expedite the therapy duration. In this study, different concentrations of AO extract (0, 5, 10, 15, and 20 wt %) were incorporated into the nanofibrous scaffolds to study their potential for the skin tissue repairing. The desired scaffolds were prepared by electrospinning the blend of poly(ε -caprolactone) and gelatin as a synthesized and natural polymer. The electrospun nanofibers were characterized by SEM, FTIR, DSC, TGA, tensile, AO extract release, and cellular culture tests. This study proposed incorporating the AO extract into the nanofibrous scaffolds for accelerating the skin tissue repairing and the optimized amount of AO extract as about 15% was introduced for offering the most desirable electrospun scaffolds for this application. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48587.     

Preparation of biomimetic three-dimensional gelatin/montmorillonite–chitosan scaffold for tissue engineering

A novel gelatin/montmorillonite–chitosan (Gel/MMT–CS) nanocomposite scaffold was prepared via the intercalation process and the freeze-drying technique, using the ice particulates as the porogen materials. Properties including pore structure, water adsorption content, in vitro degradation and tensile strength were investigated. It was demonstrated that the introduced intercalation structure endowed the Gel/MMT–CS scaffold with good mechanical properties and a controllable degradation rate. Scanning of the electron microscope images revealed that the scaffold obtained was highly porous and suitable for the implanted cells to adhere and grow. The mitochondrial activity assay provided good evidences of cells viability on the Gel/MMT–CS membranes, giving an indication of possible application as a matrix for tissue engineering.     

Fabrication and characterisation of nanofibrous polyurethane scaffold incorporated with corn and neem oil using single stage electrospinning technique for bone tissue engineering applications

In bone tissue engineering, the design of scaffolds with ECM is still challenging now-a-days. The objective of the study to develop an electrospun scaffold based on polyurethane (PU) blended with corn oil and neem oil. The electrospun nanocomposites were characterized through scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), contact angle measurement, atomic force microscopy (AFM) and tensile strength. The assays activated prothrombin time (APTT), partial thromboplastin time (PT) and hemolysis assay were performed to determine the blood compatibility parameters of the electrospun PU and their blends of corn oil and neem oil. Further, the cytocompatibility studies were performed using HDF cells to evaluate their proliferation rates in the electrospun PU and their blends. The morphology of the electrospun PU blends showed that the addition of corn oil and corn/neem oil resulted in reduced fiber diameter of about 845?±?117.86?nm and 735?±?126.49 nm compared to control (890?±?116.911?nm). The FTIR confirmed the presence of corn oil and neem oil in PU matrix through hydrogen bond formation. The PU blended with corn oil showed hydrophobic (112°?±?1) while the PU together with corn/neem oil was observed to hydrophilic (64°?±?1.732) as indicated in the measurements of contact angle. The thermal behavior of prepared PU/corn oil and PU/corn/neem oil nanocomposites were enhanced and their surface roughness were decreased compared to control as revealed in the AFM analysis. The mechanical analysis indicated the enhanced tensile strength of the developed nanocomposites (PU/corn oil - 11.88 MPa and PU/corn/neem oil - 12. 96 MPa) than the pristine PU (7.12 MPa). Further, the blood compatibility assessments revealed that the developed nanocomposites possess enhanced anticoagulant nature compared to the polyurethane. Moreover, the developed nanocomposites was non-toxic to red blood cells (RBC) and human fibroblast cells (HDF) cells as shown in the hemolytic assay and cytocompatibility studies. Finally, this study concluded that the newly developed nanocomposites with better physio-chemical characteristics and biological properties enabled them as potential candidate for bone tissue engineering.     

Hierarchical bioceramic scaffold for tissue engineering: A review

Bioceramic scaffolds have a promising application in bone-tissue engineering field. However, bioceramic scaffolds exhibit low fracture toughness; hence, to overcome this problem, hierarchical bioceramic scaffold or bioceramic scaffolds coated with polymer are produced. Starting with the fundamental requirements for bioceramic scaffold, this article provides detailed information on recent developments of method to produce porous bioceramics scaffold and hierarchical bioceramic scaffold. Chemical modifications to enhance interfacial adhesion and formation of interpenetrating network structures between the bioceramic scaffold and the natural polymer layer are discussed in this article. Areas of future research are highlighted at the end of this review.     

Gelatin electrospun nanofibrous matrices for cardiac tissue engineering applications

The generation of in vitro tissue constructs using biomaterials and cardiac cells is a promising strategy for screening novel therapeutics and their effects on cardiac regeneration. Current cardiac mimetic tissue constructs are unable to stably maintain functional characteristics of cardiomyocytes for long-term cultures. The objective of our study was to fabricate and characterize nanofibrous matrices of gelatin for prolonged cultures of primary cardiomyocytes which previously has been used as copolymer or hydrogels. Gelatin nanofibrous matrices were successfully electrospun using a benign binary solvent, cross-linked without swelling and fusing and evaluated by scanning electron microscopy (SEM) and uniaxial tensile measurement. Scaffolds exhibited modulus 19.6 ± 3.6 kPa similar to native human myocardium tissue with fiber diameters of 200–600 nm and average porosity percentage of 49.9 ± 5.6. Myoblasts showed good cell adhesion and proliferation. Neonatal rat cardiomyocytes cultured on gelatin nanofibrous matrices showing synchronized contracting cardiomyocytes (beating) for 27 days were studied by video microscopy. Confocal microscopic analysis of immunofluorescence stained sections indicated the presence of cardiac specific Troponin T in long-term cultures. Semiquantitative RT-PCR analysis of 3D versus 2D cultures revealed enhanced expression of contractile protein desmin. Our studies show that the biophysical and mechanical properties of electrospun gelatin nanofibers are ideal for in vitro engineered cardiac constructs (ECC), to explore cardiac function in drug testing and tissue replacement. Together with stem cell techniques, they may be an ideal platform for prolongedin vitro studies in alternatives to animal usage for the pharmaceutical industry.     

Chemical synthesis of biomimetic hydrogels for tissue engineering

Owing to their high water content, porous structure, biocompatibility and tissue‐like viscoelasticity, hydrogels have become attractive and promising biomaterials for use in drug delivery, three‐dimensional cell culture and tissue engineering applications. Various chemical approaches have been developed for hydrogel synthesis using monomers or polymers carrying reactive functional groups. For in vivo tissue repair and in vitro cell culture purposes, it is desirable that the crosslinking reactions occur under mild conditions, do not interfere with biological processes and proceed at high yield with exceptional selectivity. Additionally, the crosslinking reaction should allow straightforward incorporation of bioactive motifs or signaling molecules, at the same time providing tunability of the hydrogel microstructure, mechanical properties and degradation rates. In this review, we discuss various chemical approaches applied to the synthesis of complex hydrogel networks, highlighting recent developments from our group. The discovery of new chemistries and novel materials fabrication methods will lead to the development of the next generation of biomimetic hydrogels with complex structures and diverse functionalities. These materials will likely facilitate the construction of engineered tissue models that may bridge the gap between two‐dimensional experiments and animal studies, providing preliminary insight prior to in vivo assessments. © 2017 Society of Chemical Industry     

Preparation and characterization of nanohydroxyapatite strengthening nanofibrous poly(L‐lactide) scaffold for bone tissue engineering

A biomimetic nanofibrous poly(L ‐lactide) scaffold strengthened by nanohydroxyapatite particles was fabricated via a thermally induced phase separation technique. Scanning electron microscopy results showed that nanohydroxyapatite particles uniformly dispersed in the nanofibrous poly(L ‐lactide) scaffold (50–500 nm in fiber diameter) with slight aggregation at a high nHA content, but showed no influence on the interconnected macroporous and nanofibrous structure of the scaffold. The nanofibrous poly(L ‐lactide) scaffold presented a specific surface area of 34.06 m² g^?1, which was much higher than that of 2.79 m² g^?1 for the poly(L ‐lactide) scaffold with platelet structure. Moreover, the specific surface area of the nanofibrous scaffold was further enhanced by incorporating nanohydroxyapatite particles. With increasing the nanohydroxyapatite content, the compressive modulus and amount of bovine serum albumin adsorbed on the surface of the nanofibrous composite scaffold were markedly improved, as opposed to the decreased crystallinity. In comparison to poly(L ‐lactide) scaffold, both the nanofibrous poly(L ‐lactide) and poly(L ‐lactide)/nanohydroxyapatite scaffolds exhibited a faster degradation rate for their much larger specific surface area. The culture of bone mesenchymal stem cell indicated that the composite nanofibrous poly(L ‐lactide) scaffold with 50 wt % nanohydroxyapatite showed the highest cells viability among various poly(L ‐lactide)‐based scaffolds. The strengthened biomimetic nanofibrous poly(L ‐lactide)/nanohydroxyapatite composite scaffold will be a potential candidate for bone tissue engineering. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Aloe vera gel: a new thickening agent for pigment printing

An attempt was made to print cotton fabric with pigments using a new thickening agent based on Aloe vera gel in combination with sodium alginate. The results were compared with the standard conventional printing recipe containing synthetic thickener, and a favourable effect of Aloe vera introduction was achieved. The results show that the properties of the printed fabric (sharpness, colour yield, overall fastness properties, softness, and water vapour transmission) are dependent on the percentage of Aloe vera gel in the thickener combination, the concentration of printing auxiliaries, and the curing conditions. Optimal printing properties were achieved by using a printing paste containing 80% Aloe vera/20% sodium alginate (700 g kg^?1), pigment (50 g kg^?1), binder (145 g kg^?1), fixer (10 g kg^?1), and ammonium sulfate (5 g kg^?1), followed by drying at 85 °C for 5 min and curing at 150 °C for 3 min. The sample printed with the new recipe showed superior rubbing fastness and handle properties, with a slightly lower colour yield, when compared with the sample printed with synthetic thickener. Finally, economic issues arising from synthetic thickener substitution are highlighted.     

Protein encapsulated in electrospun nanofibrous scaffolds for tissue engineering applications

The main purpose of tissue engineering is the preparation of fibrous scaffolds with similar structural and biochemical cues to the extracellular matrix in order to provide a substrate to support the cells. Controlled release of bioactive agents such as growth factors from the fibrous scaffolds improves cell behavior on the scaffolds and accelerates tissue regeneration. In this study, nanofibrous scaffolds were fabricated from biocompatible and biodegradable poly(lactic‐co‐glycolic acid) through the electrospinning technique. Nanofibers with a core–sheath structure encapsulating bovine serum albumin (BSA) as a model protein for hydrophilic bioactive agents were prepared through emulsion electrospinning. The morphology of the nanofibers was evaluated by field‐emission scanning electron microscopy and the core–sheath structure of the emulsion electrospun nanofibers was observed by transmission electron microscopy. The results of the mechanical properties and X‐ray diffraction are reported. The scaffolds demonstrated a sustained release profile of BSA. Biocompatibility of the scaffolds was evaluated using the MTT (3(4,5‐ dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide) assay for NIH‐3T3 fibroblast cells. The results indicated desirable biocompatibility of the scaffolds with the capability of encapsulation and controlled release of the protein, which can serve as tissue engineering scaffolds. © 2013 Society of Chemical Industry     

Polymer-based hydrogel scaffolds for skin tissue engineering applications: a mini-review

Polymer hydrogels consist of a three-dimensional (3D) structure with cross-linked networks rich in a huge amount of water through hydrogen-bonding interactions, making them highly hydrophilic. Due to their impressive hydrophilic characteristics and cell non-cytotoxicity, polymer hydrogels are useful tissue engineering tools for the organization of cells and tissues and organ regeneration. Many biomedical engineers and researchers have recently begun to utilize polymer hydrogels as tissue or cell culture environments and as scaffolds for the stable growth of organs in tissue engineering and regeneration medicine. This paper focuses on skin regeneration in polymer hydrogels where skin is a means of protecting the body from infection or physical or chemical damage. Generally, skin tissue that has incurred minor damage or wounds can regenerate and heal in a relatively short time, while severe injuries may require transplantation or artificial skin. For those purposes, skin culturing in an in vitro environment is essential, and the environment produced using polymer hydrogel scaffolds needs to be both similar to the real environment and safe for skin cell growth. This paper reviews post-2000 skin regeneration research in the field of tissue engineering, focusing specifically on polymer hydrogels; it also discusses some of the central perspectives and key issues.     

Extracellular matrix regenerated: tissue engineering via electrospun biomimetic nanofibers

While electrospinning had seen intermittent use in the textile industry from the early twentieth century, it took the explosion of the field of tissue engineering, and its pursuit of biomimetic extracellular matrix (ECM) structures, to create an electrospinning renaissance. Over the past decade, a growing number of researchers in the tissue engineering community have embraced electrospinning as a polymer processing technique that effectively and routinely produces non‐woven structures of nanoscale fibers (sizes of 80 nm to 1.5 µm). These nanofibers are of physiological significance as they closely resemble the structure and size scale of the native ECM (fiber diameters of 50 to 500 nm). Attempts to replicate the many roles of native ECM have led to the electrospinning of a wide array of polymers, both synthetic (poly(glycolic acid), poly(lactic acid), polydioxanone, polycaprolactone, etc.) and natural (collagen, fibrinogen, elastin, etc.) in origin, for a multitude of different tissue applications. With various compositions, fiber dimensions and fiber orientations, the biological, chemical and mechanical properties of the electrospun materials can be tailored. In this review we highlight the role of electrospinning in the engineering of different tissues and applications (skin/wound healing, cartilage, bone, vascular tissue, urological tissues, nerve, and ligament), and discuss its potential role in future work. Copyright © 2007 Society of Chemical Industry     

An in vitro evaluation of Genipin-crosslinked and Hypericum perforatum incorporated novel membranes for skin tissue engineering applications

Incorporating medicinal plant extracts in membranes have a great potential as scaffolds for tissue engineering applications or vehicles for delivering therapeutic agents. Herein, Hypericum perforatum oil (0.25, 0.50, % vol/vol) loaded membranes were developed with Polyvinyl alcohol and chitosan polymer, where Genipin works as a chemical crosslinker to obtain a wound dressing material with acceptable characterization properties. Chemical groups, surface morphology, water uptake capacity, water vapor permeability rate, hydrophilicity, and mechanical properties of membranes were thoroughly investigated. Increasing oil concentration had a significant effect on the water uptake, surface morphology. and water vapor permeability rate of the membranes. Cytocompatibility of the membrane was also investigated with mouse embryonic fibroblasts (MEF) by 3-(4,5-dimethylthiazoyl-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay for direct and indirect cell culture studies. SEM was used to investigate the cell morphology on the membranes. The MTT assay findings prove that Genipin crosslinked H. perforatum oil loaded scaffolds are highly biocompatible and enhance the adhesion and proliferation of MEF cells. In addition to this, the genotoxicity test was performed to show DNA fragmentation. Results showed that the H. perforatum oil loaded polyvinyl alcohol-chitosan membrane presents suitable properties for potential skin tissue engineering applications.     

Preparation and characterization of polyhydroxybutyrate‐co‐hydroxyvalerate/silk fibroin nanofibrous scaffolds for skin tissue engineering

Nanofibrous scaffolds were obtained by co‐electrospinning poly (3‐hydroxybuty‐rate‐co‐3‐hydroxyvalerate) (PHBV) and fibroin regenerated from silk in different proportions using 1,1,1,3,3,3‐hexafluoro‐2‐isopropanol (HFIP) as solvent. Field emission scanning electron microscope (FESEM) investigation showed that the fiber diameters of the nanofibrous scaffolds ranged from 190 to 460 nm. X‐ray diffraction (XRD) and Fourier transform infrared spectroscopy analysis (FT‐IR) showed that the main structure of silk fibroin (SF) in the nanofibrous scaffold was β‐sheet. Compared to the PHBV nanofibrous scaffold, the surface hydrophilicity and water‐uptake capability of the PHBV/SF nanofibrous scaffold with 50/50 were improved. The results of cell adhesion experiment showed that the fibroblasts adhered more to the PHBV/SF nanofibrous scaffold with 50/50 than the pure PHBV nanofibrous scaffold. The proliferation of fibroblast on the PHBV/SF nanofibrous scaffold with 50/50 was higher than that on the pure PHBV nanofibrous scaffold. Our results indicated that the PHBV/SF nanofibrous scaffold with 50/50 may be a better candidate for biomedical applications such as skin tissue engineering and wound dressing. POLYM. ENG. SCI., 55:907–916, 2015. © 2014 Society of Plastics Engineers     

组织工程多孔支架微管内流场数值模拟

骨支架内部微管结构对营养液和细胞在其内部的流动有着非常重要的影响。利用流体计算软件Fluent对不同尺寸的人工骨微管结构内部营养液和细胞的流动状况进行了数值模拟,得到了不同几何结构骨支架内部流场的速度和压力分布图。结果表明,从进口到出口,主管道内流体流速随管道的深入不断减小。上端浮克曼管中流体流速比下端浮克曼管中流体流速高,但是比同一高度主管道内流体流速低。哈佛氏管与第一行浮克曼管交叉处下端的哈佛氏管内存在流动缓慢区,第三行浮克曼管与哈佛氏管交叉处开始,流体速度不断增大。随浮克曼管长度的增加,上端哈佛氏管中流体流动的缓慢区减小;随浮克曼管直径的增加,浮克曼管中的流速有所增加,并且各微管中流体的流速更为均匀;随浮克曼管与主管道夹角的增加,骨支架各微管内流体流速更加均匀,利于细胞和营养液在各管道的输运。本数值模拟范围内,最佳骨支架结构参数为浮克曼管长度3mm,直径0.6mm,浮克曼管与主管道夹角90°。     

Biomimetic porous collagen/hydroxyapatite scaffold for bone tissue engineering

Bone defect and osteochondral injury frequently occur due to diseases or traumatism and bring a crucial challenge in orthopedics. The hybrid scaffold has shown promise as a potential strategy for the treatment of such defects. In this study, a novel biomimetic porous collagen (Col)/hydroxyapatite (HA) scaffold was fabricated through assembling layers of Col containing gradual amount of HA under the assistance of “iterative layering” freeze‐drying process. The scaffold presents a double gradient of highly interconnected porosity and HA content from top to bottom, mimicking the inherent physiological structure of bone. Owing to the biomimetic structure and component, significant increase of cell proliferation, alkaline phosphatase activity, and osteogenic differentiation in vitro was observed, illustrating potential application of the excellent Col/HA scaffold as a promising strategy for bone tissue engineering. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45271.     

Preparation and characterization of porous scaffold composite films by blending chitosan and gelatin solutions for skin tissue engineering

Biodegradable polymers have significant potential in biotechnology and bioengineering. However, for some applications, they are limited by their inferior mechanical properties and unsatisfactory compatibility with cells and tissues. In the present investigation blends of chitosan and gelatin with various compositions were produced as candidate materials for biomedical applications. Fourier transform infrared spectral analysis showed good compatibility between these two biodegradable polymers. The composite films showed improved tensile properties, highly porous structure, antimicrobial activities, low water dissolution, low water uptake and high buffer uptake compared to pure chitosan or gelatin films. These enhanced properties could be explained by the introduction of free ? OH, ? NH₂ and ? NHOCOCH₃ groups of the amorphous chitosan in the blends and a network structure through electrostatic interactions between the ammonium ions (? NH³⁺) of the chitosan and the carboxylate ions (? COO^?) of the gelatin. Scanning electron microscopy images of the blend composite films showed homogeneous and smooth surfaces which indicate good miscibility between gelatin and chitosan. The leafy morphologies of the scaffolds indicate a large and homogeneous porous structure, which would cause increased ion diffusion into the gel that could lead to an increase in stability in aqueous solution, buffer and temperature compared to the gelatin/chitosan system. In vivo testing was done in a Wistar rat (Rattus norvegicus) model and the healing efficiencies of the scaffolds containing various compositions of chitosan were measured. The healing efficiencies in Wistar rat of composites with gelatin to chitosan ratios of 10:3 and 10:4 were compared with that of a commercially available scaffold (Eco‐plast). It was observed that, after 5 days of application, the scaffold with a gelatin to chitosan ratio of 10:3 showed 100% healing in the Wistar rat; however, the commercial Eco‐plast showed only a little above 40% healing of the dissected rat wound. Copyright © 2012 Society of Chemical Industry     

Fabrication of protein‐doped PLA composite nanofibrous scaffolds for tissue engineering

BACKGROUND: Electrospinning is known as a novel fabrication method to form nanofibrous scaffolds for tissue‐engineering application. Previously, many natural biopolymers of protein have been electrospun. However, keratin has not attracted enough attention. In this study, keratin and gelatin were co‐electrospun with polylactide (PLA), respectively. RESULTS: The resulting nanofibers were characterized by a field emission scanning electron microscope (FE‐SEM), an attenuated total reflection‐Fourier transform infrared spectroscopy (ATR‐FTIR), and an electron spectroscopy for chemical analysis (ESCA). The biodegradation of mats in the presence of trypsin solution was studied. Cell attachment experiments showed that NIH 3T3 cells adhered more and spread better onto the PLA/keratin and PLA/gelatin nanofibrous mats than that onto the blank PLA mats. MTT and BrdU assay showed that PLA/keratin and PLA/gelatin nanofibrous mats could both accelerate the viability and proliferation of fibroblast cells as compared to PLA nanofibrous mats. CONCLUSION: The present study suggests that the introduction of gelatin and keratin can both improve cell‐material interaction, especially, the former is more effective. Copyright © 2008 Society of Chemical Industry     

A porous hydroxyapatite scaffold for bone tissue engineering: Physico-mechanical and biological evaluations

Polymer sponge replication method was used in this study to prepare the macroporous hydroxyapatite scaffolds with interconnected oval shaped pores of 100-300 μm with pore wall thickness of ∼50 μm. The compression strength of 60 wt.% HA loaded scaffold was 1.3 MPa. The biological response of the scaffold was investigated using human osteoblast like SaOS2 cells. The results showed that SaOS2 cells were able to adhere, proliferate and migrate into pores of scaffold. Furthermore, the cell viability was found to increase on porous scaffold compared to dense HA. The expression of alkaline phosphate, a differentiation marker for SaOS2 cells was enhanced as compared to nonporous HA disc with respect to number of days of culture. The enhanced cellular functionality and the ability to support osteoblast differentiation for porous scaffolds in comparison to dense HA has been explained in terms of higher protein absorption on porous scaffold.     

Production of the biomimetic small diameter blood vessels for cardiovascular tissue engineering

A novel biomimetic vascular graft scaffolds were produced by electrospinning method with the most superior characteristics to be a proper biomimetic small diameter blood vessel using Polycaprolactone(PCL), Ethyl Cellulose(EC) and Collagen Type-1 were used to create the most convenient synergy of a natural and synthetic polymer to achieve similarity to native small diameter blood vessels. Scanning Electron Microscopy(SEM), Fourier Transform Infrared Spectroscopy(FTIR), Differential Scanning Calorimetry Analysis(DSC), tensile measurement tests, and in-vitro and in-vivo applications were performed. Results indicated significant properties such as having 39.33?nm minimum, 104.98?nm average fiber diameter, 3.2?MPa young modulus and 135% relative cell viability.