Macrophage responses to silk

Plasma Processes and Polymers, 2013

Silk fibroin biopolymer is anisotropically etched using oxygen and argon/oxygen plasma. At room temperature, silk removal rates are 0.25 mm min À1 . Scanning electron micrographs show that silk fibroin is a heterogeneous material for which plasma etching reveals a silk backbone structure as the matrix is more quickly volatilized. A simple physical model of silk etching accurately predicts the etch rate without any fitting parameters. The model and experimental data show that atomic oxygen, in the absence of ion bombardment, only slowly etches silk (<0.017 mm min À1 ) and does not spontaneously etch silk fibroin backbone structures. Rather, the silk constituents must be removed by first covering the surface with adsorbed atomic oxygen which is then simultaneously desorbed through energetic ion bombardment.

Cells Tissues Organs, 2013

ithelialization compared with the control scaffolds without sericin but lower numbers of macrophages and multinucleated giant cells. These results indicate that the delivery of sericin from the novel genipin-crosslinked scaffolds efficiently healed the wound. Therefore, these genipin-crosslinked sericin/PVA scaffolds represent a promising candidate for the accelerated healing of full-thickness wounds.

Journal of Applied Polymer Science, 2014

Microencapsulation is becoming increasingly important in the food, cosmetics, and medicinal industries due to its potential for stabilization and delivery of volatile and delicate compounds. Novel food-safe techniques for encapsulating oil in silk biomaterials using emulsion-based processes that exploit silk's unique properties (including amphiphilicity, biocompatibility, aqueous and ambient processing, and tunable physical crosslinking behavior) are described. The sonication-induced self-assembly of silk previously applied to hydrogel fabrication replaced the use of the thermal or chemical suspension crosslinking traditionally used to stabilize the aqueous protein phase in emulsions. Stable, physically crosslinked silk micro-and macro-particles loaded with oil or water-soluble dye were produced by aliquoting sonicated silk solutions into an oil bath. Oil micro-droplets emulsified in aqueous silk solutions did not impede the self-assembly of silk into films or hydrogel networks. In O/W/O emulsions, particle morphology and silk permeability to a model lipophilic dye in the interior phase were controllable via processing.

Journal of Tissue Engineering and Regenerative Medicine, 2010

Bombyx mori and is used for fibre distribution. In this study, we used a subcutaneous implantation model in Wistar rats to examine SF scaffolds prepared by treating the degummed cocoon with FA for either 30 or 60 min. The tissue reaction and inflammatory response to SF was assessed by qualitative histology at intervals from 3 to 180 days. Additionally, dynamic biomaterial-induced vascularization and biomaterial degradation were quantified using a technique for analysing an image of the entire implanted biomaterial. Varying the FA treatment time led to different scaffold morphologies and resulted in two distinct peri-implant tissue reactions. The 30 min-treated scaffold was integrated into the surrounding tissue beginning at day 3 after implantation and vascularization increased 10fold from 15 to 180 days, while the scaffold was continuously degraded throughout the first 90 days. In contrast, the 60 min-treated SF scaffold appeared as bulk for the first 90 days after implantation, after which a rapid degradation and vascularization process began. After 180 days, the tissue response was similar for both scaffolds, with eventual formation of a well vascularized connective tissue integrating the SF fibres. This study indicates that by modifying the FA treatment time, the tissue reaction to SF scaffolds can be tailored for different tissue-engineering applications. The tunability and biocompatibility of SF make it an attractive scaffold for exploration in regenerative medicine and clinical tissue engineering.

Textile Research Journal, 2015

The degumming process to remove sericin decreases silk fiber strength; however, the impact of degumming on the mechanical properties of regenerated silk biomaterials has not been established. This study investigated the effect of degumming temperature, time, alkaline component and alkaline concentration on the mechanical properties of silk fibroin films. Sericin removal was estimated using weight loss; 10 samples with 12.2-29.4% weight loss were then further characterized in terms of fiber mechanical properties, fiber surface morphology, molecular weight distribution and film tensile strength. A negative correlation was found between weight loss and fiber tensile strength. This loss of fiber strength under harsher degumming conditions had a direct impact on the tensile strength of regenerated films. Mild degumming conditions (weight loss of 12.2%) led to higher film strength (8.9 MPa), whereas aggressive degumming conditions (with 29.4% weight loss) resulted in significantly weaker films (4.3 MPa). The presence of some residual sericin, after mild degumming, is likely to affect the mechanical properties of the regenerated silk films. These results will assist in the development of materials with mechanical and biocompatibility properties tuned to specific biomedical applications.

Advanced Functional Materials

Corneal blindness is one of the most common causes of vision loss worldwide, affecting millions of people. To treat these patients, researchers have been examining different approaches to engineer corneal scaffolds suitable for transplantation. Scaffolds have been developed to replace part or all of the cornea depending on the patient requirements. Both acellular and cell-seeded scaffolds have been tested in animal models. Materials that have been under investigation for manufacturing scaffolds include collagen, silk fibroin, amniotic membrane, decellularized cornea, fibrin, chitosan, gelatin, agarose, alginate, and hyaluronic acid in addition to several synthetic polymers. Different combinations of materials, fiber crosslinking techniques, and incorporation of bioactive molecules have also been examined. Factors such as the physical properties, cytocompatibility, degradation behavior, and optical characteristics have to be considered when selecting a suitable scaffold material. Recent advancements in materials fabrication techniques such as bioprinting, electrospinning, and different collagen alignment techniques, allow scaffolds to be generated that more accurately mimic the structure of the corneal stroma. A number of scaffolds have commenced clinical trials to determine their suitability for corneal regeneration.

International journal of molecular sciences, 2017

The aim of this study was to exploit silk fibroin&#39;s properties to develop innovative composite microcarriers for mesenchymal stem cell (MSCs) adhesion and proliferation. Alginate microcarriers were prepared, added to silk fibroin solution, and then treated with ethanol to induce silk conformational transition. Microcarriers were characterized for size distribution, coating stability and homogeneity. Finally, in vitro cytocompatibility and suitability as delivery systems for MSCs were investigated. Results indicated that our manufacturing process is consistent and reproducible: silk/alginate microcarriers were stable, with spherical geometry, about 400 μm in average diameter, and fibroin homogeneously coated the surface. MSCs were able to adhere rapidly onto the microcarrier surface and to cover the surface of the microcarrier within three days of culture; moreover, on this innovative 3D culture system, stem cells preserved their metabolic activity and their multi-lineage differe...

Journal of Materials Science: Materials in Medicine, 2013

The objective of this study was to determine a silk-collagen fiber ratio for an anterior cruciate ligament (ACL) reconstruction composite scaffold device. Composite fiber scaffolds with silk volumes C14 % and collagen volume \86 % demonstrated comparable or greater initial ultimate tensile stress relative to the human ACL. Silk scaffolds implanted subcutaneously and intraarticularly in rabbits demonstrated an 84 and 92 % reduction in strength with a 26 and 22 % reduction in volume after 8 weeks, respectively. The mechanical degradation findings of this preliminary study suggest that a composite scaffold with an initial UTS value of at least 129 MPa, or roughly a 48:52 silk to collagen volume ratio meets the minimal mechanical requirements necessary to proceed to a functional ACL reconstruction study in vivo. Abbreviations ACL Anterior cruciate ligament UTS Ultimate tensile stress EDC 1-Ethyl-3-(3-dimethylaminopropyl) carbodiimide TES N-Tris(hydroxymethyl)methyl-2aminoethane sulfonic acid PBS Phosphate-buffered saline

Journal of Applied Biomedicine

In traditional medicine, natural silk is regarded as a cognitive enhancer and a cure for ameliorating the symptoms of heart disease, atherosclerosis, and metabolic disorders. In this review, general characteristics of both silk proteins, fibroin and sericin, extracted from silkworm Bombyx mori and their potential use in the neuronal disorders was discussed. Evidence shows that silk proteins exhibit neuroprotective effects in models of neurotoxicity. The antioxidant, neuroprotective, and acetylcholinesterase inhibitory mechanisms of silk proteins could prove promising in the treatment of neurodegenerative diseases. Owing to their excellent neurocompatibility and physicochemical properties, silk proteins have been used as scaffolds and drug delivery materials in the neuronal tissue engineering. These data support the potential of silk proteins as an effective complementary agent for central and peripheral neurological disorders.

Frontiers in Pediatrics

Several congenital disorders can cause end stage bladder disease and possibly renal damage in children. The current gold standard therapy is enterocystoplasty, a bladder augmentation using an intestinal segment. However, the use of bowel tissue is associated with numerous complications such as metabolic disturbance, stone formation, urine leakage, chronic infections, and malignancy. Urinary diversions using engineered bladder tissue would obviate the need for bowel for bladder reconstruction. Despite impressive progress in the field of bladder tissue engineering over the past decades, the successful transfer of the approach into clinical routine still represents a major challenge. In this review, we discuss major achievements and challenges in bladder tissue regeneration with a focus on different strategies to overcome the obstacles and to meet the need for living functional tissue replacements with a good growth potential and a long life span matching the pediatric population.

Biotechnology and Applied Biochemistry, 2010

The present study investigated the chemical properties and antityrosinase activities of SS (silk sericin) extracted from different Thai silk strains via various extraction methods. Different silk strains contain distinct SS with various amino acid compositions, which are significantly influenced by the extraction method used. Urea extraction of SS was the only method that provided clearly distinguishable bands and had the most significant impact on SS conformation as illustrated by FTIR (Fourier-transform infrared) spectra. The use of urea or either acidic or alkaline chemicals in the extraction process also influenced SS thermal behaviour. With regard to biological activity, SS extracted using urea exhibited the highest antityrosinase activity, whereas alkali-degraded SS showed no inhibition of mushroom tyrosinase. Pigments, primarily flavonoids and carotenoids from silk cocoons, were also found to enhance tyrosinase inhibition of SS.

European Journal of Science and Technology

Öz İpek, fibroin (lifli protein) ve serisin (globüler, zamklama proteini) olarak isimlendirilen iki ana proteinden oluşmaktadır. Fibroin tekstil üretiminde ve çeşitli biyomalzeme uygulamalarında kullanılırken, serisin tekstil endüstrisinde bir atık malzeme olarak kabul edilmektedir. Serisin, belirsiz bir yapıya sahip çok bileşenli bir protein olması nedeniyle, fibroinden daha az dikkat çekmiştir, ancak bu proteinin de biyolojik aktiviteye sahip olduğu ve biyouyumlu olduğu yapılan çalışmalarla gösterilmiştir. Serisin değişken amino asit bileşimi ve çeşitli fonksiyonel grupları ile biyomedikal uygulamalar için ilgi çekici biyoaktif özelliklere sahiptir. Antioksidan karakteri, nemlendirme yeteneği ve memeli hücreleri üzerindeki mitojenik etkisi nedeniyle, serisinin hücre kültürü ve doku mühendisliğinde yararlı olduğu son yıllarda yapılan çalışmalarla gösterilmiştir. Ayrıca, keratinositler ve fibroblastlar üzerindeki olumlu etkileri, başta yara bakım malzemeleri olmak üzere deri dokusu onarımı için serisin bazlı biyomalzemelerin gelişmesine yol açmıştır. Ek olarak, serisin, kemik benzeri hidroksiapatit nükleasyonunu indükleme kabiliyeti nedeniyle kemik doku mühendisliği için kullanılma potansiyeline de sahip olduğu gösterilmiştir. Filmler, süngerler ve hidrojeller gibi kararlı ipek serisin biyomalzemeleri, çapraz bağlama veya diğer polimerler ile karıştırılarak hazırlanmaktadır. Serisin aynı zamanda ilaç salımı için de kullanılma potansiyeline sahiptir, çünkü kimyasal reaktivitesi ve pH yanıtı, serisin bazlı nano-mikropartiküllerin, hidrojellerin ve konjuge moleküllerin üretimini kolaylaştırmakta ve ilaçların biyoaktivitesini arttırmaktadır. Bu çalışmada, önemli bir protein olan ipek serisinin özellikleri ve kullanım alanları özetlenmiştir.

Maxillofacial plastic and reconstructive surgery, 2016

Silk cocoon is composed of multiple layers. The natural silk cocoon containing all layers was cut as a rectangular shape as defined as total group. The inner and outermost layers were removed from the total group and the remained mat was defined as the middle group. The objectives of this study was to compare the total group with the middle group as a barrier membrane for the guided bone regeneration. The effects of these materials on the cellular proliferation and alkaline phosphatase (ALP) expression of MG63 cells were explored. For comparing bone regeneration ability, bilateral bone defects were created in calvarial areas in ten adult New Zealand white rabbits. The defects were covered with silk membranes of the middle group, with silk membrane of the total group used as the control on the contralateral side. The defects were allowed to heal for 4 and 8 weeks. Micro-computerized tomography (μCT) and histological examination were performed. The middle group exhibited a higher MTT ...

Journal of Applied Polymer Science, 2013

Superporous materials based on two proteins, collagen and sericin were synthesized by freeze-drying considering various ratios between the two proteins. To evaluate the influence of sericin content on the structure/properties relationship, the obtained scaffolds were further characterized using spectroscopic analysis, thermal, and mechanical techniques. Scanning electron microscopy was used to investigate the morphological structure of the scaffolds and the swelling properties as well as the stability of the scaffolds were also assessed. V

Cells sense and respond to scaffold pore geometry and mechanical stimuli. Many fabrication methods used in bone tissue engineering render structures with poorly controlled pore geometries. Given that cell-scaffold interactions are complex, drawing a conclusion on how cells sense and respond to uncontrolled scaffold features under mechanical loading is difficult. Here, monodisperse templated scaffolds (MTSC) were fabricated and used as a well-defined porous scaffolds to study the effect of dynamic culture conditions on bone-like tissue formation. Human bone marrow derived stromal cells were cultured on MTSC or conventional salt-leached scaffolds (SLSC) for up to 7 weeks, either under static or dynamic conditions. Spinner flask bioreactors were used to provide dynamic culture conditions to apply mechanical loading on the seeded cells through wall shear stress. The influence of controlled spherical pore geometry of MTSC subjected to static or dynamic conditions on the cell response, sp...

There is significant research dedicated to fibroin and sericin, the two major proteinaceous components of the silk threads produced by the domesticated silkworm, Bombyx mori. While fibroin is accepted as an established biomaterial, sericin (BMSS) has been largely neglected in this respect on the account of a hypothetical allergenic activity. Research over the past decade, including our previous study (Prog Biomater 2:14, 2013), demonstrated the biocompatibility of sericin and feasibility of its use as a biomaterial. However, the current procedures for isolating BMSS from the raw silk cocoons can only provide degraded proteins, where the size and distribution of their molecular masses are significantly altered. Based on the plausible assumption that such effects can have a negative impact on the properties of sericin as a biomaterial, in this study we investigated comparatively four different extraction procedures in order to find the method that would cause the least hydrothermal degradation of BMSS. The products resulting from commonly used procedures (extraction in boiling water, alkaline extraction, and extraction in autoclave) were compared to those resulting from aqueous extraction in mild conditions as described a long time ago by Anderlini. The molecular mass distribution in BMSS resulting from each procedure was examined by electrophoretic analysis performed on sodium dodecyl sulphate-polyacrylamide gel (SDS-PAGE), while the conformational changes pertaining to secondary structure of BMSS were evaluated by Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectrometry. The electrophoretograms indicated that the aqueous extraction in mild conditions conducted at 50°C for durations up to 4 weeks, with/without stirring, afforded the least degraded BMSS. The infrared spectrometric analysis showed that BMSS resulting from the mild extraction method contained predominantly b-sheet conformations, while the more degradative methods (alkaline, autoclave) led to BMSS where the random-coil conformations were preferential. The long-duration aqueous extraction at 50°C (but not at 60°C) appeared as a valid option for obtaining BMSS products where the hydrothermally induced fragmentation of the polypeptidic components is minimized. Keywords Bombyx mori silk Á Silk proteins Á Sericin Á Methods of extraction Á Molecular mass distribution Á Electrophoresis Á FTIR analysis Abbreviations BMSF Bombyx mori silk fibroin BMSS Bombyx mori silk sericin FTIR-ATR Fourier transform infrared-attenuated total reflectance MMCO Molecular-mass cutoff SDS-PAGE Sodium dodecyl sulphate-polyacrylamide gel electrophoresis

The Immune Response to Implanted Materials and Devices

Biomaterials have gained tremendous attention in regenerative medicine and tissue engineering applications due to their ability to enhance functional tissue regeneration. After implantation of biomaterial-based device or drug carrier, it comes in contact with surrounding cells and consequently elicits confi ned and/or chronic infl ammatory responses. The immune responses to biomaterials do not depend only on the method of implantation such as surgery and injection but also depend on source of biomaterials and their physicochemical properties such as molecular weight, chemical composition, mechanical properties and degradation rate. Therefore, it is necessary to thoroughly understand the biological responses to the implanted biomaterials. In this chapter, a brief discussion about different natural and synthetic biomaterials and their infl ammatory responses is provided. Different strategies to minimize the immune response have also been discussed.

Bioengineering, 2022

Governed by established structure–property relationships, peptide motifs comprising major ampullate spider silk confer a balance of strength and extensibility. Other biologically inspired small peptide motifs correlated to specific functionalities can be combined within these units to create designer silk materials with new hybrid properties. In this study, a small basic peptide, (ARKKAAKA) known to both bind heparin and mimic an antimicrobial peptide, was genetically linked to a protease-resistant, mechanically robust silk-like peptide, MaSp2. Purified fusion proteins (four silk domains and four heparin-binding peptide repeats) were expressed in E. coli. Successful fusion of a MaSp2 spider silk peptide with the heparin-binding motif was shown using a variety of analytical assays. The ability of the fusion peptide to bind heparin was assessed with ELISA and was further tested for its anticoagulant property using aPTT assay. Its intrinsic property to inhibit bacterial growth was eval...

Advanced Materials, 2021

Some of the most abundant biomass on earth is sequestered in fibrous biopolymers like cellulose, chitin, and silk. These types of natural materials offer unique and striking mechanical and functional features that have driven strong interest in their utility for a range of applications, while also matching environmental sustainability needs. However, these material systems are challenging to process in cost-competitive ways to compete with synthetic plastics due to the limited options for thermal processing. This results in the dominance of solution-based processing for fibrous biopolymers, which presents challenges for scaling, cost, and consistency in outcomes. However, new opportunities to utilize thermal processing with these types of biopolymers, as well as fibrillation approaches, can drive renewed opportunities to bridge this gap between synthetic plastic processing and fibrous biopolymers, while also holding sustainability goals as critical to long-term successful outcomes.

Journal of biomedical materials research. Part B, Applied biomaterials, 2016

Large osteochondral defects have been difficult to repair via tissue engineering treatments due to the lack of a sufficient number of source cells for repairing the defect and to the severe mechanical stresses affecting the replacement tissue. In the present study, whole-area osteochondral defects of rabbit patella were covered and wrapped with a fibroin sponge containing chondrocytes, with or without Green Fluorescent Protein (GFP) transgenic marking, on the surface facing the osteochondral defect. Five of eight osteochondral defects that were covered with the chondrocyte-seeded fibroin sponges showed hyaline cartilage-like repair containing no fibroin fragments at 6 weeks after surgery. The repaired tissue showed a layer formation, which showed intensive safranin-O and toluidine blue staining, and which showed positive type II collagen immunostaining. The average surface coverage of the repaired cartilage was 53%. On average, 48% of the cells in the repaired tissue were derived fr...

International journal of molecular sciences, 2018

Electrospinning has been used for decades to generate nano-fibres via an electrically charged jet of polymer solution. This process is established on a spinning technique, using electrostatic forces to produce fine fibres from polymer solutions. Amongst, the electrospinning of available biopolymers (silk, cellulose, collagen, gelatine and hyaluronic acid), chitosan (CH) has shown a favourable outcome for tissue regeneration applications. The aim of the current review is to assess the current literature about electrospinning chitosan and its composite formulations for creating fibres in combination with other natural polymers to be employed in tissue engineering. In addition, various polymers blended with chitosan for electrospinning have been discussed in terms of their potential biomedical applications. The review shows that evidence exists in support of the favourable properties and biocompatibility of chitosan electrospun composite biomaterials for a range of applications. Howeve...

Progress in Biomaterials, 2013

Natural biomaterials such as collagen, silk fibroin, and chitosan, and synthetic biopolymers such as polylactic acid, polycaprolactone, polyglycolic acid, and their copolymers are being used as scaffold for tissue engineering applications. In the present work, a fibrous mat was electrospun from eri silk fibroin (ESF). A composite of hydroxyapatite (Hap) and the ESF scaffold was prepared by soaking the ESF scaffold in a solution of calcium chloride and then in sodium diammonium phosphate. The average tensile stress of the pure ESF and hydroxyapatite-coated ESF scaffold (ESF-Hap) was found to be 1.84 and 0.378 MPa, respectively. Pure ESF and ESF-Hap scaffolds were evaluated for their characteristics by a themogravimetric analyzer and Fourier transform infrared spectroscope. The crystallinity and thermal stability of the ESF-Hap scaffold were found to be more than that of uncoated eri silk nanofiber scaffold. The water uptake of the pure ESF and ESF-Hap scaffolds was found to be 69% an...

Journal of Biomedical Materials Research Part A, 2015

Inflammatory responses to biomaterials heavily influence the environment surrounding implanted devices, often producing foreign body reactions. The macrophage is a key immunomodulatory cell type consistently associated with implanted biomaterials and routinely employed in short term in vitro cell studies of biomaterials aiming to reproduce host responses. Inconsistencies within these studies, including differently sourced cells, different durations of culture, and assessment of different activation markers, lead to many conflicting results in vitro that confound consistency and conclusions. We hypothesize that different experimentally popular monocyte-macrophage cell types have intrinsic in vitro culture-specific differences that yield conflicting results. Recent studies demonstrate changes in cultured macrophage cytokine expression over time, leading to the hypothesis that changes in macrophage phenotype also occur in response to extended culture. Here, macrophage cells of different transformed and primary-derived origins were cultured for 21 days on model polymer biomaterials. Cell type-based differences in morphology and cytokine/ chemokine expression as well as changes in cell surface biomarkers associated with differentiation stage, activation state, and adhesion were compared. Results reflect consistent macrophage development towards an M2 phenotype via up-regulation of the macrophage mannose receptor for all cell types following 21-day extended culture. Significantly, implanted biomaterials experiencing the foreign body response and encapsulation in vivo often elicit a shift towards an analogous M2 macrophage phenotype. In vitro "default" of macrophage cultures, regardless of lineage, to this M2 state in the presence of biomaterials at long culture periods is not recognized but has important implications to in vitro modeling of in vivo host response.

Macromolecular Research, 2014

The aim of this study was to evaluate silkworm-cocoon-derived silk membrane (SM) for application in guided bone regeneration (GBR) and to compare it with commercially available GBR membranes, such as collagen membrane (CM) and polytetrafluoroethylene membrane (PM). The SM, CM, and PM membranes were examined via scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) analysis, and tensile strength evaluation. Thirty rats were used for the experiments. Critical-sized parietal bone defects (diameter: 8.0 mm) were divided into three groups according to the applied GBR membrane. The rats were sacrificed 4 or 8 weeks after surgery and evaluated by micro-computerized tomography (μ-CT) and histology. The FTIR analysis of the SM was similar to that of the CM. The SEM images showed that the surface characteristics of the SM differed from those of the CM and PM. The SM showed a complex network structure of silk fibers. The wet SM was also more resistant to tensile stress than the wet CM and PM. The μ-CT results of the animal study showed that the bone volume of the SM group was higher than those of the CM and PM groups 4 weeks after the operation (p<0.05). The histological analysis showed that the new bone regeneration of the SM group was higher than those of the CM and PM groups 4 and 8 weeks after the operation (p<0.05). This study demonstrated that the tensile strength of the wet SM was higher than the tensile strength of the wet CM and PM groups. The bone formation of the SM group was higher than those of the other two groups.

Scientific reports, 2017

To understand the osteogenic effect of the middle layer of the silk cocoon, sericin was examined for its cellular effects associated with tumor necrosis factor-α (TNF-α) signaling in this study. The fragmented sericin proteins in the silk mat were evaluated for the TNF-α expression level in murine macrophages. The concentration of protein released from silk mats was higher in the outermost and the innermost layers than in the middle layers, and the protein released from the silk mat was identified as sericin. The level of TNF-α in murine macrophages was dependent on the applied concentration of sericin, and the expression of genes associated with osteogenesis in osteoblast-like cells was dependent on the applied concentration of TNF-α. In animal experiments, silk mats from the middle layers led to a higher regenerated bone volume than silk mats from the innermost layer or the outermost layer. If TNF-α protein was incorporated into the silk mats from the middle layers, bone regenerat...

Natural Product Communications, 2013

Silk sericin was found to suppress the production of pro-inflammatory cytokines, which are related to the inflammatory reaction. The objectives of this study were to investigate the anti-inflammatory effect of sericin in vivo using the carrageenan-induced rat edema model and changes in the histology of tissues. The effects of sericin on the expression of COX-2 and iNOS were also evaluated. Sericin solutions at 0.004-0.080 mg/mL were applied topically to the top of the hind paw and carrageenan (1.0 mg) was injected subcutaneously to the plantar surface of the right hind paw. Our results indicated that sericin significantly reduced the inflammation in rats’ paw compared with the negative control (water and acetone) and its effect at 0.080 mg/mL was only slightly lower than that of 1.0% w/v indomethacin. Similar numbers of polymorphonuclear and macrophage cells were found in rats’ tissue treated with indomethacin and sericin solution, while the numbers were significantly higher in thei...

BioMed Research International, 2016

Silk sericin is a natural polymer produced by silkworm,Bombyx mori, which surrounds and keeps together two fibroin filaments in silk thread used in the cocoon. The recovery and reuse of sericin usually discarded by the textile industry not only minimizes environmental issues but also has a high scientific and commercial value. The physicochemical properties of the molecule are responsible for numerous applications in biomedicine and are influenced by the extraction method and silkworm lineage, which can lead to variations in molecular weight and amino acid concentration of sericin. The presence of highly hydrophobic amino acids and its antioxidant potential make it possible for sericin to be applied in the food and cosmetic industry. The moisturizing power allows indications as a therapeutic agent for wound healing, stimulating cell proliferation, protection against ultraviolet radiation, and formulating creams and shampoos. The antioxidant activity associated with low digestibility...

Journal of the Indian Institute of Science, 2019

Introduction Biomaterial by definition is any material that is intended for use in the fabrication of medical device or implant/graft to replace function of defective body tissue in a safe, economic and reliable manner 1. An ideal biomaterial endowed with biocompatibility, bioactivity, biodegradability, immuno-compatibility and mechanical resilience determines its suitability for use in various biomedical applications. In addition, the biomaterial must also possess appropriate material processing attributes to yield it into different formats. Advances in the field of material science have led to the discovery of novel biomaterials in the past few decades to fuel the revolutionary concept of bringing an ideal biomaterial to clinical

Applied Microbiology and Biotechnology, 2011

Wound dressings have experienced continuous and significant changes over the years based on the knowledge of the biochemical events associated with chronic wounds. The development goes from natural materials used to just cover and conceal the wound to interactive materials that can facilitate the healing process, addressing specific issues in non-healing wounds. These new types of dressings often relate with the proteolytic wound environment and the bacteria load to enhance the healing. Recently, the wound dressing research is focusing on the replacement of synthetic polymers by natural protein materials to delivery bioactive agents to the wounds. This article provides an overview on the novel protein-based wound dressings such as silk fibroin keratin and elastin. The improved properties of these dressings, like the release of antibiotics and growth factors, are discussed. The different types of wounds and the effective parameters of healing process will be reviewed.

Frontiers in Bioengineering and Biotechnology

Objective: Increasing the mass and/or activity of brown adipose tissue (BAT) is one promising avenue for treating obesity and related metabolic conditions, given that BAT has a high potential for energy expenditure and is capable of improving glucose and lipid homeostasis. BAT occurs either in discrete “classical” depots, or interspersed in white adipose tissue (WAT), termed “inducible/recruitable” BAT, or ‘beige/brite’ adipocytes. We and others have demonstrated that bone morphogenetic protein 7 (BMP7) induces brown adipogenesis in committed and uncommitted progenitor cells, resulting in increased energy expenditure and reduced weight gain in mice. BMP7 is therefore a reliable growth factor to induce browning of WAT.Methods: In this study, we sought to deliver BMP7 specifically to subcutaneous (sc)WAT in order to induce tissue-resident progenitor cells to differentiate into energy-expending recruitable brown adipocytes, without off-target effects like bone formation, which can occu...

Environment Conservation Journal

Silk protein, sericin was isolated from raw silk fabrication in reeling industry and subsequent process of silk throwing. The majority of it is thrown in the waste water from silk manufacturing. Sericin was used in antibacterial, antioxidant, wound healing, moisturising, and antiaging medications and cosmetics. Limited reports on the use of sericin in the treatment of diabetes prompted the current study on the use of sericin in the control of diabetes in rats. Thus, the present study was aimed to investigate the antihyperglycemic activity of sericin protein using rat model. The results indicated that sericin treated groups showed a noteworthy augment in body weight than the standard drug (Metformin) treatment with diabetic control. Sericin @ 400mg/kg showed 152.6 mg/dl and 141.2 mg/dl on 7th and 21st day of treatment. Similarly, Sericin @ 800mg/kg showed 126.0 mg/dl and 114.0 mg/dl on 7th and 21st day of treatment when compared to control (206.0 mg/dl and 203.6 mg/dl). SGOT of 68.4 ...

International Journal of Molecular Sciences, 2021

Tissue engineering (TE) is the approach to combine cells with scaffold materials and appropriate growth factors to regenerate or replace damaged or degenerated tissue or organs. The scaffold material as a template for tissue formation plays the most important role in TE. Among scaffold materials, silk fibroin (SF), a natural protein with outstanding mechanical properties, biodegradability, biocompatibility, and bioresorbability has attracted significant attention for TE applications. SF is commonly dissolved into an aqueous solution and can be easily reconstructed into different material formats, including films, mats, hydrogels, and sponges via various fabrication techniques. These include spin coating, electrospinning, freeze drying, physical, and chemical crosslinking techniques. Furthermore, to facilitate fabrication of more complex SF-based scaffolds with high precision techniques including micro-patterning and bio-printing have recently been explored. This review introduces th...

Progress in Natural Science: Materials International, 2020

Patterning the neuronal cells via inkjet printing of self-assembled peptides on silk scaffolds.

Polymers, 2018

SF/polyurethane composite non-woven sheet was fabricated to evaluate the cardiovascular tissue engineering materials in the wet state. The compatibility and microstructure analyses were carried out on the fabricated SF/polyurethane composite non-woven sheet by thermal analysis and solid-state NMR analysis in the wet state. To evaluate the modulus of elasticity, a tensile test was performed and supported with dynamic viscoelasticity and mechanical analysis. Results showed that SF/polyurethane composites form domains within the non-woven sheet and are in a finely dispersed state while maintaining their structures at a scale of several tens of nm. Moreover, an increase of the loss tangent with low elastic modulus proved that a micromolecular interaction occurs between silk fibroin (SF) and polyurethane molecules.

Materials Today Communications, 2020

The ability of Bombyx mori Thai silk fibroin (SF) to stimulate IL-10 production from peripheral blood mononuclear cells (PBMCs) derived from healthy and atopic subjects was investigated. We evaluated a safety profile and anti-inflammatory properties of Thai SF, compared to two commercially available biomaterials for wound care and implant, Gelfoam® and Ologen®, by incubating them with PBMCs before determining cell viability and cytokine expression. The results demonstrated that Thai SF was neither toxic to PBMCs nor induces the release of inflammatory cytokines (Th1/Th17-related cytokines and Th2-related cytokines). Interestingly, Thai SF, but not other biomaterials, could stimulate IL-10 production from PBMCs harvested from both healthy individuals and atopic subjects. As IL-10 has an anti-inflammatory and scar preventive properties, our findings indicate that Thai SF is a promising biomaterial for wound dressing in both healthy individuals and in patients who are prone to develop allergic reactions.

International Journal of Molecular Sciences

Growth factors, including fibroblast growth factor-7 (FGF-7), are a group of proteins that stimulate various cellular processes and are often used with carriers to prevent the rapid loss of their activities. Sericin with great biocompatibility has been investigated as a proteinaceous carrier to enhance the stability of incorporated proteins. The difficulties in obtaining intact sericin from silkworm cocoons and the handling of growth factors with poor stability necessitate an efficient technique to incorporate the protein into a sericin-based biomaterial. Here, we report the generation of a transgenic silkworm line simultaneously expressing and incorporating FGF-7 into cocoon shells containing almost exclusively sericin. Growth-factor-functionalized sericin cocoon shells requiring simple lyophilization and pulverization processes were successfully used to induce the proliferation and migration of keratinocytes. Moreover, FGF-7 incorporated into sericin-cocoon powder exhibited remark...

PLOS ONE, 2011

Background: In the field of Plastic Reconstructive Surgery the development of new innovative matrices for skin repair is in urgent need. The ideal biomaterial should promote attachment, proliferation and growth of cells. Additionally, it should degrade in an appropriate time period without releasing harmful substances, but not exert a pathological immune response. Spider dragline silk from Nephila spp meets these demands to a large extent. Methodology/Principal Findings: Native spider dragline silk, harvested directly out of Nephila spp spiders, was woven on steel frames. Constructs were sterilized and seeded with fibroblasts. After two weeks of cultivating single fibroblasts, keratinocytes were added to generate a bilayered skin model, consisting of dermis and epidermis equivalents. For the next three weeks, constructs in co-culture were lifted on an originally designed setup for air/liquid interface cultivation. After the culturing period, constructs were embedded in paraffin with an especially developed program for spidersilk to avoid supercontraction. Paraffin cross-sections were stained in Haematoxylin & Eosin (H&E) for microscopic analyses. Native spider dragline silk woven on steel frames provides a suitable matrix for 3 dimensional skin cell culturing. Both fibroblasts and keratinocytes cell lines adhere to the spider silk fibres and proliferate. Guided by the spider silk fibres, they sprout into the meshes and reach confluence in at most one week. A well-balanced, bilayered cocultivation in two continuously separated strata can be achieved by serum reduction, changing the medium conditions and the cultivation period at the air/liquid interphase. Therefore spider silk appears to be a promising biomaterial for the enhancement of skin regeneration.