Novo sistema de liberação de drogas ­ filme de fibroína de seda carregado ou não com insulina para reparo de feridas em mucosa palatina: estudo in vitro e clínico randomizado / A new drug delivery system ­ silk fibroin film loaded or not with insulin on palatal mucosa wound healing: in vitro study and a randomized clinical trial

Several types of periodontal and peri-implant soft tissue defects require surgical treatment to reestablish function and aesthetics. However, local, and systemic factors can jeopardize tissue repair leading to unexpected outcomes and postoperative discomfort. In order to overcome this problem, new devices have been developed to improve surgical procedures outcomes and patient experience. The aim of the present study was to develop a new silk fibroin (SF)/chitosan (CH) film loaded with insulin as a drug delivery system to improve palatal donor area healing after free gingival graft harvesting for ridge preservation. For this, biomaterial development, characterization and in vitro assessment were performed to evaluate the new delivery system. In addition, 3- months outcomes from palatal wound healing following the use of the proposed delivery system were assessed through clinical, patient centered parameters, immunological, microbiological, and histological evaluations. Sixty-nine patients with indication of tooth extraction were enrolled into 3 groups: Control Group (C) (n=23): open wound on palatal mucosa followed by spontaneous healing; SF/CH Film (F) (n=23): open wound on palatal mucosa and silk fibroin film as dressing; Insulin-loaded SF/CH film (IF) (n=23): open wound on palatal mucosa and an insulin- loaded silk fibroin film as a delivery system. : It was verified some characteristics that are favorable to the oral environment, such as mechanical properties, swelling and permeability to water vapor. The biomaterial presented a standard of a controlled release system through diffusion with delivery stability in human saliva, along with an excellent biocompatibility with the absence of cytotoxicity and genotoxicity increasing cell viability in lineage cells (HaCat). F and IF promoted accelerated palatal wound closure on day 7 and 14 after surgery, as well as an early epithelialization, compared to the C group. Both films were capable to reduce pro-inflammatory cytokines (IL-6, TNF-α, IL-1ß) and modulate biomarkers correlated to tissue degradation/remodeling. Spontaneous healing microbiome reported higher genus/species with pathogenic role in the oral mucosa with reduction in health species following this profile until de end of the follow-up. A tendency of eubiosis was observed in F and IF groups throughout healing process. It seems that this new device has a promising application in oral cavity and positively influence wound healing. (AU)

Diversos tipos de defeitos mucogengivais requerem abordagem cirúrgica para o reestabelecimento funcional e estético. Porém, alterações locais e sistêmicas podem prejudicar o processo de reparo gerando resultados inesperados e desconforto ao paciente. Biomateriais vem sendo desenvolvidos para melhorar os resultados dos procedimentos cirúrgicos e a experiência clínica do paciente. O objetivo do presente estudo foi desenvolver um filme de fibroína de seda (FS) e quitosana (QT) carregado com insulina (INS), atuando como um sistema de liberação, para acelerar a cicatrização de feridas na área doadora palatina após procedimento de preservação de rebordo com uso de enxerto gengival livre. Para isso, foi executado o desenvolvimento, caracterização e avaliação in vitro do biomaterial. Ademais, o resultado de 3 meses do reparo das feridas palatinas foi verificado por meio de avaliações clínicas, imunológica, microbiológica, histológica, bem como parâmetros centrados no paciente. Sessenta e nove pacientes foram alocados aleatoriamente nos grupos Controle (C) (n=23): ferida aberta em palato seguido de cicatrização espontânea; Filme de FS/QT (F) (n=23): ferida aberta em palato associada ao filme na área doadora; Filme de FS/QT carregado com INS (IF) (n=23): ferida aberta em palato associada ao filme carregado com INS na área doadora. Verificou-se propriedades mecânicas, bem como de entumecimento e permeabilidade ao vapor de água, favoráveis ao meio bucal sem nenhuma alteração com a inclusão da INS. O dispositivo apresentou liberação controlada por meio de difusão com estabilidade em saliva humana. Excelente biocompatibilidade com ausência de cito e genotoxicidade foi observada em diversos tipos celulares aumentando a viabilidade celular em células de linhagem (HaCat). F e IF favoreceram um fechamento acelerado da ferida palatina aos 7 e 14 dias pós-injuria, assim como uma epitelização precoce destes comparado ao grupo C. F e IF reduziram citocinas pró-inflamatórias (IL6, TNF-α, IL-1ß) além de apresentarem função modulatória na quantificação de biomarcadores relacionados a degradação tecidual. O Grupo C apresentou gênero/espécies com potencial patogênico e redução de microrganismos relacionados a saúde mantendo este perfil aos 14 e 30 dias. Enquanto isso, uma tendência a eubiose foi observado em F e IF ao longo do processo de cicatrização. Deste modo, verifica-se a aplicação promissora do novo dispositivo na cavidade oral bem como capacidade de influenciar positivamente o reparo da mucosa oral. (AU)

Preparation of silk fibroin/hyaluronic acid composite hydrogel based on thiol-ene click chemistry / 浙江大学学报·医学版

OBJECTIVES@#To design and prepare silk fibroin/hyaluronic acid composite hydrogel.@*METHODS@#The thiol modified silk fibroin and the double-bond modified hyaluronic acid were rapidly cured into gels through thiol-ene click polymerization under ultraviolet light condition. The grafting rate of modified silk fibroin and hyaluronic acid was characterized by 1H NMR spectroscopy; the gel point and the internal microstructure of hydrogels were characterized by rheological test and scanning electron microscopy; the mechanical properties were characterized by compression test; the swelling rate and degradation rate were determined by mass method. The hydrogel was co-cultured with the cells, the cytotoxicity was measured by the lactate dehydrogenase method, the cell adhesion was measured by the float count method, and the cell growth and differentiation on the surface of the gel were observed by scanning electron microscope and fluorescence microscope.@*RESULTS@#The functional group substitution degrees of modified silk fibroin and hyaluronic acid were 17.99% and 48.03%, respectively. The prepared silk fibroin/hyaluronic acid composite hydrogel had a gel point of 40-60 s and had a porous structure inside the gel. The compressive strength was as high as 450 kPa and it would not break after ten cycles. The water absorption capacity of the composite hydrogel was 4-10 times of its own weight. Degradation experiments showed that the hydrogel was biodegradable, and the degradation rate reached 28%-42% after 35 d. The cell biology experiments showed that the cytotoxicity of the composite gel was low, the cell adhesion was good, and the growth and differentiation of the cells on the surface of the gel were good.@*CONCLUSIONS@#The photocurable silk fibroin/hyaluronic acid composite hydrogel can form a gel quickly, and has excellent mechanical properties, adjustable swelling rate and degradation degree, good biocompatibility, so it has promising application prospects in biomedicine.

Silk fibroin/collagen composite hydrogels with different matrix stiffness influence the growth and phenotype of human mammary epithelial cells / 生理学报

Extracellular matrix (ECM) stiffness is closely related to the physiological and pathological states of breast tissue. The current study was aimed to investigate the effect of silk fibroin/collagen composite hydrogels with adjustable matrix stiffness on the growth and phenotype of normal breast epithelial cells. In this study, the enzymatic reaction of horseradish peroxidase (HRP) with hydrogen peroxide (H2O2) was used to change the degree of cross-linking of the silk fibroin solution. The rotational rheometer was used to characterize the composite hydrogel's biomechanical properties. Human normal mammary epithelial cell line MCF-10A were inoculated into composite hydrogels with various stiffness (19.10-4 932.36 Pa) to construct a three dimensional (3D) culture system of mammary epithelial cells. The CCK-8 assay was applied to detect the cell proliferation rate and active states in each group. Hematoxylin-Eosin (HE) staining and whole-mount magenta staining were used for histological evaluation of cell morphology and distribution. The results showed that with the increase of matrix stiffness, MCF-10A cells exhibited inhibited proliferation rate, decreased formation of acinus structures and increased branching structures. Meanwhile, with the increase of matrix stiffness, the polarity of MCF-10A cells was impeded. And the increase of matrix stiffness up-regulated the expression levels of mmp-2, mmp-3, and mmp-9 in MCF-10A cells. Among the genes related to epithelial-mesenchymal transition (EMT), the expression level of the epithelial marker gene E-cadherin was significantly down-regulated, while the interstitial cell marker gene Vimentin was up-regulated, and the expression levels of Snail, Wnt5b and Integrin β1 in the Wnt pathway were up-regulated. These results suggest that the silk fibroin/collagen composite hydrogels with adjustable matrix stiffness regulates the proliferation and the phenotype of MCF-10A cells. The effects of increased matrix stiffness may be closely related to the changes of the polar structures and function of MCF-10A cells, as well as the occurrence of ECM-remodeling and EMT.

Recovery of motor function in rats with complete spinal cord injury following implantation of collagen/silk fibroin scaffold combined with human umbilical cord-mesenchymal stem cells

SUMMARY OBJECTIVE: This study aimed to assess the effect of the collagen/silk fibroin scaffolds seeded with human umbilical cord-mesenchymal stem cells on functional recovery after acute complete spinal cord injury. METHODS: The fibroin and collagen were mixed (mass ratio, 3:7), and the composite scaffolds were produced. Forty rats were randomly divided into the Sham group (without spinal cord injury), spinal cord injury group (spinal cord transection without any implantation), collagen/silk fibroin scaffolds group (spinal cord transection with implantation of the collagen/silk fibroin scaffolds), and collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group (spinal cord transection with the implantation of the collagen/silk fibroin scaffolds co-cultured with human umbilical cord-mesenchymal stem cells). Motor evoked potential, Basso-Beattie-Bresnahan scale, modified Bielschowsky's silver staining, and immunofluorescence staining were performed. RESULTS: The BBB scores in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group were significantly higher than those in the spinal cord injury and collagen/silk fibroin scaffolds groups (p<0.05 or p<0.01). The amplitude and latency were markedly improved in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group compared with the spinal cord injury and collagen/silk fibroin scaffolds groups (p<0.05 or p<0.01). Meanwhile, compared to the spinal cord injury and collagen/silk fibroin scaffolds groups, more neurofilament positive nerve fiber ensheathed by myelin basic protein positive structure at the injury site were observed in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group (p<0.01, p<0.05). The results of Bielschowsky's silver staining indicated more nerve fibers was observed at the lesion site in the collagen/silk fibroin scaffolds + human umbilical cord-mesenchymal stem cells group compared with the spinal cord injury and collagen/silk fibroin scaffolds groups (p<0.01, p< 0.05). CONCLUSION: The results demonstrated that the transplantation of human umbilical cord-mesenchymal stem cells on a collagen/silk fibroin scaffolds could promote nerve regeneration, and recovery of neurological function after acute spinal cord injury.

Preparation Method of Silk Fibroin and Its Application in Field of Biomedical Materials / 中国医疗器械杂志

Silk fibroin has the characteristics of good biocompatibility, mechanical properties, degradation performance and easy shaping, which makes silk fibroin become the focus of biomedical material preparation and research, and has received extensive attention. This article reviews the prior art methods of silk fibroin degumming, dissolution and regeneration processing. The specific applications of silk fibroin materials in the field of biomedical materials are reviewed, and the application prospects of silk fibroin in the field of biomedical materials are prospected.

Atividade antimicrobiana das nanoestruturas de fibroína de seda / Antimicrobial activity of silk fibroine nanoparticles

A segurança alimentar e nutricional são fatores que, atualmente, estão em crescente preocupação. Apesar da existência de práticas de higiene na manipulação e produção de alimentos, é necessário aplicar novas metodologias para redução de patologias causadas por contaminação alimentícia que ocorrem por diversas bactérias, que estão relacionados com as Doenças Veiculadas por Alimentos (DVAs). Em especial, temos a Escherichia coli, Enterobacter cloacae, Staphylococcus aureus e Salmonella typhi. O objetivo do trabalho foi de avaliar a atividade antimicrobiana das Nanoestruturas de Fibroína de Seda com tamanho médio de 250,7 ± 10,4 nm sobre as bactérias supracitadas. As concentrações de nanopartículas utilizadas não alcançaram a concentração inibitória mínima, necessitando de estudos posteriores para obter essa concentração.

Analysis of protective mechanism of silk protein based cryoprotectants / 生物医学工程学杂志

Dimethyl sulfoxide (Me SO) supplemented with fetal bovine serum (FBS) is a widely used cryoprotectant combination. However, high concentration of Me SO is toxic to cells, and FBS presents problems related to diseases such as bovine spongiform encephalopathy and viral infections. Silk protein is a kind of natural macromolecule fiber protein with good biocompatibility and hydrophilicity. The aim of this paper is to analyze the cryoprotective mechanism of silk protein as cryoprotectant. Firstly, differential scanning calorimetry (DSC) was used to measure the thermal hysteresis activity (THA) of silk protein. The THA of 10 mg/mL sericin protein was 0.96°C, and the THA of 10% (V/V) fibroin protein was 1.15°C. Then the ice recrystallization inhibition (IRI) of silk protein-PBS solution was observed with cryomicroscope. The cold stage was set at - 7°C, after 40 minutes' incubation, the mean grain size rate (MGSR) of sericin protein and fibroin protein were 28.99% and 3.18%, respectively, which were calculated relative to phosphate buffer saline (PBS) control. It is indicated that sericin and silk fibroin have certain effects of inhibiting recrystallization of ice crystals. Finally, the structure and physicochemical properties of silk protein were analyzed by Fourier transform infrared spectroscopy (FTIR). The results showed that the content of the random coil was 75.62% and the β-sheet structure was 24.38% in the secondary of sericin protein. The content of the β-sheet structure was 56.68%, followed by random coil structure 22.38%, and α-helix 16.84% in the secondary of fibroin protein. The above analysis demonstrates the feasibility of silk fibroin as a cryoprotectant, and provides a new idea for the selection of cryoprotectants in the future.

Lentivirus-mediated BMP-2 overexpression plasmid transfection into bone marrow mesenchymal stem cells combined with silk fibroin scaffold for osteoblast transformation / 中国骨伤

OBJECTIVE@#To explore the effect of lentivirus-mediated BMP-2 overexpression plasmid transfection into bone marrow mesenchymal stem cells and silk fibroin scaffold on osteoblast transformation.@*METHODS@#The lentivirus BMP-2 overexpression vector was constructed, bone marrow mesenchymal stem cells were cultured, and the combined culture system of nuclear scaffolds was constructed. Alizarin red staining and alkaline phosphatase staining were used to detect the osteogenic transformation of bone marrow mesenchymal stem cells in vitro. Ten New Zealand white rabbits, weighing 3.2 to 4.5 kg(averaging 3.9 kg), aged (2.89±0.45) years old, were selected to construct the rabbit tibial defect model by drilling a conical tibial defect (5 mm in length, 2 mm in width and 3 mm in depth) with an oral drill. The repair of the tibial defect in the animal model was observed by HE staining. The experimental group was implanted with silk fibroin scaffold + BMP-2 overexpression vector bone marrow mesenchymal stem cell complex, while the negative control group was implanted with silk fibroin scaffold+non-transfected bone marrow mesenchymal stem cell complex.@*RESULTS@#Compared with the control group(silk fibroin scaffold+non-transfected bone marrow mesenchymal stem cells), the number of adherent cells on the surface of the scaffold in the experimental group(silk fibroin scaffold+transfected BMP-2 overexpression vector BMP-2 complex) increased significantly. Compared with the control group, the ECM secretion in the experimental group increased significantly. EDX analysis showed that the content of calcium ion was 0.22% in the control group and 0.86% in the experimental group, which showed that the ability of inducing calcium ion formation in the experimental group was stronger than that in the control group. Alizarin red staining of calcium nodules showed that there was no obvious change in the naked eye of the control group, and a small amount of calcium nodules could be seen under the microscope. In the experimental group, obvious red area staining was observed by naked eye, and a large number of calcium nodules were observed by microscopy. The results of alkaline phosphatase staining showed that there was no obvious change in the naked eye of the control group, and no obvious change in the microscopic observation. In the experimental group, purple area staining was observed by naked eyes, and ALP staining was strongly positive by microscopy. The combined culture system of silk fibroin scaffold and bone marrow mesenchymal stem cells can repair cartilage defects. The repair effect of BMP-2 bone marrow mesenchymal stem cells after transfection is obviously better than that of non-transfection group. HE staining showed that inflammatory cells decreased and scaffolds disappeared slightly in the control group. In the experimental group, inflammatory cells were significantly reduced, scaffolds disappeared and angiogenesis was observed.@*CONCLUSIONS@#Lentivirus-mediated BMP-2 overexpression plasmid can promote BMSC to differentiate into osteocytes and secrete more extracellular matrix containing Ca²⁺ to promote bone defect repair.

Carbon-Fiber Based Microelectrode Array Embedded with a Biodegradable Silk Support for In Vivo Neural Recording

BACKGROUND: Recently, carbon fibers have been utilized to develop a depth-type microelectrode array for chronic neural recording. Since the diameter of carbon fibers is smaller than the conventional electrodes made of metal wires or microfabricated silicon, the carbon fiber electrodes showed an improved capability for chronic neural recording with less tissue damages. However, the carbon fiber based microelectrodes have a limitation of short insertion depth due to a low stiffness. METHODS: We proposed a carbon fiber based microelectrode array embedded with a mechanical support structure to facilitate the penetration into the deeper brain. The support is made of biodegradable silk fibroin to reduce the reactive tissue responses. The 4-channel carbon fiber based microelectrode arrays were fabricated and accessed in terms of electrochemical impedance, recording capability for 1-month implantation in rat hippocampi. The electrodes with tungsten supports were fabricated and tested as a control group. Immunohistochemical analysis was performed to identify the reactive glial responses. RESULTS: The carbon fiber based electrode arrays with silk supports showed about 2-fold impedance increase 2 weeks after implantation while the number of active electrodes decreased simultaneously. However, after 1 month, the electrode impedance decreased back to its initial value and the percentage of active electrodes also increased above 70%. Immunohistochemical staining clearly showed that the electrodes with silk supports induced less reactive glial responses than that with tungsten supports. CONCLUSION: The proposed carbon fiber based microelectrode array is expected to be used for long-term in vivo neural recording from deep brain regions with the minimized reactive tissue response.

Preparation and characterization of oriented scaffolds derived from cartilage extracellular matrix and silk fibroin / 华西口腔医学杂志

OBJECTIVE@#This study aims to prepare oriented scaffolds derived from a cartilage extracellular matrix (CECM) and silk fibroin (SF) and use to investigate their physicochemical property in cartilage tissue engineering.@*METHODS@#Oriented SF-CECM scaffolds were prepared from 6% mixed slurry (CECM：SF=1：1) through modified temperature gradient-guided thermal-induced phase separation, followed by freeze drying. The SF-CECM scaffolds were evaluated by scanning electron microscopy (SEM) and histological staining analyses and determination of porosity, water absorption, and compressive elastic modulus of the materials.@*RESULTS@#The SEM image showed that the SF-CECM scaffolds contained homogeneous reticular porous structures in the cross-section and vertical tubular structures in the longitudinal sections. Histological staining showed that cells were completely removed, and the hybrid scaffolds retained proteogly can and collagen. The composition of the scaffold was similar to that of natural cartilage. The porosity, water absorption rate, and vertical compressive elastic modulus of the scaffolds were 95.733%±1.010%, 94.309%±1.302%, and (65.40±4.09) kPa, respectively.@*CONCLUSIONS@#The fabricated SF-CECM scaffolds exhibit satisfactory physicochemical and biomechanical properties and thus could be an ideal scaffold in cartilage tissue engineering.

Preparation of Drug Eluting Natural Composite Scaffold Using Response Surface Methodology and Artificial Neural Network Approach

Silk fibroin/xanthan composite was investigated as a suitable biomedical material for controlled drug delivery, and blending ratios of silk fibroin and xanthan were optimized by response surface methodology (RSM) and artificial neural network (ANN) approach. A non-linear ANN model was developed to predict the effect of blending ratios, percentage swelling and porosity of composite material on cumulative percentage release. The efficiency of RSM was assessed against ANN and it was found that ANN is better in optimizing and modeling studies for the fabrication of the composite material. In-vitro release studies of the loaded drug chloramphenicol showed that the optimum composite scaffold was able to minimize burst release of drug and was followed by controlled release for 5 days. Mechanistic study of release revealed that the drug release process is diffusion controlled. Moreover, during tissue engineering application, investigation of release pattern of incorporated bioactive agent is beneficial to predict, control and monitor cellular response of growing tissues. This work also presented a novel insight into usage of various drug release model to predict material properties. Based on the goodness of fit of the model, Korsmeyer–Peppas was found to agree well with experimental drug release profile, which indicated that the fabricated material has swellable nature. The chloramphenicol (CHL) loaded scaffold showed better efficacy against gram positive and gram negative bacteria. CHL loaded SFX55 (50:50) scaffold shows promising biocomposite for drug delivery and tissue engineering applications.

Development of Printable Natural Cartilage Matrix Bioink for 3D Printing of Irregular Tissue Shape

The extracellular matrix (ECM) is known to provide instructive cues for cell attachment, proliferation, differentiation, and ultimately tissue regeneration. The use of decellularized ECM scaffolds for regenerative-medicine approaches is rapidly expanding. In this study, cartilage acellular matrix (CAM)-based bioink was developed to fabricate functional biomolecule-containing scaffolds. The CAM provides an adequate cartilage tissue–favorable environment for chondrogenic differentiation of cells. Conventional manufacturing techniques such as salt leaching, solvent casting, gas forming, and freeze drying when applied to CAM-based scaffolds cannot precisely control the scaffold geometry for mimicking tissue shape. As an alternative to the scaffold fabrication methods, 3D printing was recently introduced in the field of tissue engineering. 3D printing may better control the internal microstructure and external appearance because of the computer-assisted construction process. Hence, applications of the 3D printing technology to tissue engineering are rapidly proliferating. Therefore, printable ECM-based bioink should be developed for 3D structure stratification. The aim of this study was to develop printable natural CAM bioink for 3D printing of a tissue of irregular shape. Silk fibroin was chosen to support the printing of the CAM powder because it can be physically cross-linked and its viscosity can be easily controlled. The newly developed CAM-silk bioink was evaluated regarding printability, cell viability, and tissue differentiation. Moreover, we successfully demonstrated 3D printing of a cartilage-shaped scaffold using only this CAM-silk bioink. Future studies should assess the efficacy of in vivo implantation of 3D-printed cartilage-shaped scaffolds.

Application of a Collagen Patch Derived from Duck Feet in Acute Tympanic Membrane Perforation

We investigated the utility of the duck-feet collagen extraction patching procedure in the traumatic tympanic membrane (TM) perforation via a comparison with spontaneous healing or paper patch. Fifty-six ears of adult male Sprague-Dawley rats, each weighing in the range of 250 to 300 g, were used for the animal studies. Sixteen rats had one-side ear in the control group and the opposite-side ear in the treated groups. The remaining twelve rats had a one-side ear with the duck-feet collagen patch and the opposite-side ear with a paper patch. The proliferating cell nuclear antigen (PCNA) expression cells were calculated among the 200 basal cells, and the expression percentage was identified as the labeling index. The healing of the perforation in the duck-feet collagen patch group was confirmed to be more rapid compared to the healing of the other groups. PCNA staining was observed in the migrating portion of PCNA enhanced cell to collagen scaffold in Post operative day (POD) 7 of collagen patch group. Thus, the adhesive effect of the duck-feet collagen patch to perforated margin was better than that of the paper patch. After completing the healing process, the collagen patch shrank and detached from the tympanic membrane (POD 14). In this study, we confirmed that the use of a duck-feet collagen patch had the advantage of early healing, inducing natural TM contour, and disappearing ability after the patch effect is complete.

Evaluación de la fibroína de seda como biomaterial de soporte para el crecimiento de células mesenquimales estromales de pulpa dental / Evaluation of silk fibroin as a support biomaterial for the growth of stromal mesenchymal cells of dental pulp

La regeneración de tejidos usando células, factores de crecimiento y soportes constituyen una alternativa en la Medicina Regenerativa. La fibroína de seda es un excelente biosoporte, sus propiedades mecánicas únicas le permiten soportar procesos de adhesión y crecimiento celular. Objetivo. Evaluar la fibroína de la seda obtenida del gusano de seda Bombyx mori L como material de soporte para el crecimiento de células mesenquimales estromales de pulpa dental (CMPD). Métodos. La fibroína obtenida a partir de capullos de gusanos de seda Bombyx mori L criados en la Granja El Pílamo, propiedad de la Universidad Tecnológica de Pereira, se empleó para la fabricación de películas de fibroína íntegras y resistentes a condiciones de cultivo. Las CMPD fueron obtenidas a partir de un donante de diente premolar, la pieza dental se cortó con disco de diamante para la obtención de la pulpa que fue sometida a disgregación enzimática. Las células obtenidas se subcultivaron hasta el segundo pase, para posteriormente transferirse a cajas de cultivo que contenían películas de fibroína, se sometieron a condiciones inherentes al proceso de incubación siguiendo su crecimiento y viabilidad celular durante 27 días. Resultados. Al final del periodo de incubación, se observaron películas integras, estables y resistentes que permitieron el crecimiento celular. Conclusión. Se plantea el uso de fibroína como un biopolímero natural que brinda un soporte mecánico, un microambiente óptimo y un mimetismo de la estructura organizacional de los tejidos, postulándose como un potencial biomaterial para procesos de crecimiento celular en Medicina Regenerativa e Ingeniería de Tejidos.(AU)

Tissue regeneration using cells, growth factors and supports are an alternative in Regenerative Medicine. Silk fibroin is an excellent biosupport, its unique mechanical properties allow it to support processes of cell adhesion and growth. Objective: Evaluating the obtained silk´s fibroin from silkworm (Bombyx mori L) as a scaffold material for growth of dental pulp mesenchymal stromal cells (CMPD). Methods: The fibroin was obtained from silkworm (Bombyx mori L) cocoons reared at "The Pilamo" Farm, owned by the Universidad Tecnológica de Pereira. Procedures for obtaining full and resistant fibroin films to culture conditions were performed. The CMPD were obtained from a premolar tooth, the tooth was cut with a diamond blade to obtain the pulp which was subjected to enzymatic digestion. The cells obtained were subcultured until the second pass, and then, transferred to culture dishes containing fibroin films. This cells were cultured in standard conditions and tracking incubation with cell viability and growth for 27 days. Results: At the end of the incubation period, we realize that the fibroin films were intact and also this fibroin films allows cell growth.Conclusion: The use of fibroin as a natural biopolymer provides mechanical support, also an optimal microenvironment and mimic the organizational structure of tissues, so we postulated fibroin as a potential biomaterial for cell growth to be used in regenerative medicine and tissue engineering.(AU)

Fabrication and Characterization of Hydrocolloid Dressing with Silk Fibroin Nanoparticles for Wound Healing

Hydrocolloid dressings have been developed for many types of wound healing. In particular, dressing is a critical component in the successful recover of burn injuries, which causes a great number of people to not only suffer from physical but also psychological and economic anguish each year. Additionally, silk fibroin is the safest material for tissue engineering due to biocompatibility. In this study, we fabricated hydrocolloid dressings incorporating silk fibroin nanoparticles to enhance the efficacy of hydrocolloid dressing and then use this silk fibroin nanoparticle hydrocolloid dressing (SFNHD) in animal models to treat burn wounds. The structures and properties of SFNHD were characterized using tensile strength and Cell Counting Kit-8 assay. The results indicated the structural stability and the cellular biocompatibility of the hydrocolloid dressing suggesting that SFNHD can be applied to the treatment of wounds. To demonstrate the capacity of a silk fibroin hydrocolloid dressing to treat burn wounds, we compared SFNHD to gauze and Neoderm®, a commercially available dressing. This study clearly demonstrated accelerated wound healing with greater wound structural integrity and minimal wound size after treatment with SFNHD. These observations indicate that SFNHD may be an improvement upon current standard dressings such as Gauze and Neoderm® for burn wounds.

Electrospun Fibrous Silk Fibroin/Poly(L-Lactic Acid) Scaffold for Cartilage Tissue Engineering

For successful tissue engineering of articular cartilage, a scaffold with mechanical properties that match those of natural cartilage as closely as possible is needed. In the present study, we prepared a fibrous silk fibroin (SF)/poly(L-lactic acid) (PLLA) scaffold via electrospinning and investigated the morphological, mechanical, and degradation properties of the scaffolds fabricated using different electrospinning conditions, including collection distance, working voltage, and the SF:PLLA mass ratio. In addition, in vitro cell-scaffold interactions were evaluated in terms of chondrocyte adhesion to the scaffolds as well as the cytotoxicity and cytocompatibility of the scaffolds. The optimum electrospinning conditions for generating a fibrous SF/PLLA scaffold with the best surface morphology (ordered alignment and suitable diameter) and tensile strength (~1.5 MPa) were a collection distance of 20 cm, a working voltage of 15 kV, and a SF:PLLA mass ratio of S50P50. The degradation rate of the SF/PLLA scaffolds was found to be determined by the SF:PLLA mass ratio, and it could be increased by reducing the PLLA proportion. Furthermore, chondrocytes spread well on the fibrous SF/PLLA scaffolds and secreted extracellular matrix, indicating good adhesion to the scaffold. The cytotoxicity of SF/PLLA scaffold extract to chondrocytes over 24 and 48 h in culture was low, indicating that the SF/PLLA scaffolds are biocompatible. Chondrocytes grew well on the SF/PLLA scaffold after 1, 3, 5, and 7 days of direct contact, indicating the good cytocompatibility of the scaffold. These results demonstrate that the fibrous SF/PLLA scaffold represents a promising composite material for use in cartilage tissue engineering.

Sensitization to silk allergen among workers of silk filatures in India: a comparative study

BACKGROUND: Sericulture plays an eminent role in development of rural economy in India. Silk filature is a unit where silk is unwound from the cocoons and the strands are collected into skeins. During the process workers are exposed to the high molecular weight proteins like Sericin and Fibroin which are potent allergens leading to sensitization over a period of time and subsequently occupational related health disorders. OBJECTIVE: To identify and compare the magnitude of silk allergen sensitization in workers of silk filatures. METHODS: A community based comparative descriptive study was conducted for a period of 1 year at Ramanagara in south India. One hundred twenty subjects working in the silk filatures formed the study group. For comparison, 2 types of controls were selected viz.120 subjects who were not working in the silk filatures but resided in the same geographical area (control A) and 360 subjects who were not working in silk filatures as well not residing in the same geographical area (control B). Skin prick test was used to identify the silk allergen sensitization. RESULTS: Mean age was 34.14 ± 2.84 years in the study group. Mean age was 40.59 ± 14.40 years and 38.54 ± 12.20 years in control A and control B, respectively. There were 35 males (29.16%) and 85 females (70.84%) in the study group. There were 58 (48.34%) males and 62 (51.66%) females and 152 (42.2%) males and 208 females (57.8%) in control A and control B, respectively. Sensitization to silk allergen was 35.83% in the study group and 20.83% in the control group A and 11.11% in control group B. There was difference in the allergen sensitivity between the study group and control groups and it was statistically significant (chi-square = 38.08; p < 0.001). CONCLUSION: There is high burden of silk allergen sensitization among silk filature workers.

Cell attachment and proliferation of osteoblast-like MG63 cells on silk fibroin membrane for guided bone regeneration / 대한악안면성형재건외과학회지

BACKGROUND: The aim of this study is to verify the feasibility of using silk fibroin (SF) as a potential membrane for guided bone regeneration (GBR). METHODS: Various cellular responses (i.e., cell attachment, viability, and proliferation) of osteoblast-like MG63 cells cultured on an SF membrane were quantified. After culturing on an SF membrane for 1, 5, and 7 days, the attachment and surface morphology of MG63 cells were examined by optical and scanning electron microscopy (SEM), cell viability was determined using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and cell proliferation was quantified using 4',6-diamidino-2-phenylindole (DAPI) fluorescence staining. RESULTS: Optical microscopy revealed that MG63 cells cultured on the SF membrane proliferated over the 7-day observation period. The viability of cells cultured on SF membranes (SF group) and on control surfaces (control group) increased over time (P 0.05). In contrast, cell proliferation was significantly higher in the SF membrane group than in the control group at 7 days (P < 0.05). CONCLUSIONS: These results suggest that silk fibroin is a biocompatible material that could be used as a suitable alternative barrier membrane for GBR.

Uso de biomateriales a partir de la fibroína de la seda de gusano de seda (bombyx mori L. ) para procesos de medicina regenerativa basada en ingeniería de tejidos / Fibroin from silkworm (bombyx mori L ) as biomaterial used in regenrative medicine process based on tissue engineering

La regeneración de tejidos usando células, andamios y factores de crecimiento apropiados es un enfoque clave en las terapias de regeneración de tejido o de órganos. La fibroína de la seda, ha demostrado que puede ser utilizada eficazmente como un material de andamiaje en estos tratamientos. Las fibras de seda se obtienen de diversas fuentes animales, tales como arañas, gusanos de seda, escorpiones, ácaros y las moscas. La seda extraída a partir de capullos del gusano de seda (Bombyx mori L), se caracteriza por sus excelentes propiedades mecánicas, biocompatibilidad y biodegradabilidad que le permiten ser una fuente adecuada para el desarrollo de dispositivos biomédicos. La combinación única de elasticidad, resistencia y compatibilidad con células de mamíferos hace de la fibroína de la seda un material atractivo para la ingeniería de tejidos. Esta revisión aborda el procesamiento de fibroína de la seda en diferentes formas de biomateriales, sus aplicaciones, ventajas y limitaciones como biomaterial de andamiaje en la ingeniería ósea, vascular, de piel, cartílagos, ligamentos, tendones y de tejidos cardíaco, nervioso, ocular y vesical.

Tissue regeneration using cells, scaffolds and appropriate growth factors is a key approach in therapy for tissue or organs regeneration. The fibroin from silk has been shown to be effectively used as a scaffold material in these treatments. Silk fibers are obtained from various animal sources, such as spiders, silkworms, scorpions, mites and flies. The silk extracted from silkworm's (Bombyx mori L.) cocoons, is characterized by its excellent mechanical properties, biocompatibility and biodegradability this characteristics makes silk be a suitable source for the development of biomedical devices. The unique combination of elasticity, strength and compatibility with mammalian cells made of silk fibroin attractive for tissue engineering material. This review addresses the processing of silk fibroin in different forms of biomaterials, applications, advantages and limitations as a biomaterial scaffold in tissue engineering for bone, vascular tissues, skin, cartilage, ligaments, tendons, heart tissue, nervous , eye and bladder.

Clinical Outcomes of Silk Patch in Acute Tympanic Membrane Perforation

OBJECTIVES: The silk patch is a thin transparent patch that is produced from silk fibroin. In this study, we investigated the treatment effects of the silk patch in patients with traumatic tympanic membrane perforation (TTMP). METHODS: The closure rate, otorrhea rate, and closure time in all patients and the closure time in successful patients were compared between the paper patch and silk patch groups. RESULTS: Demographic data (gender, site, age, traumatic duration, preoperative air-bone gap, and perforation size and location) were not significantly different between the two groups. The closure rate and otorrhea rate were not significantly different between the two groups. However, the closure time was different between the two groups (closure time of all patients, P=0.031; closure time of successful patients, P=0.037). CONCLUSION: The silk patch which has transparent, elastic, adhesive, and hyper-keratinizing properties results in a more efficient closure time than the paper patch in the treatment of TTMP patients. We therefore believe that the silk patch should be recommended for the treatment of acute tympanic membrane perforation.