Preparation，characterization，in vitro drug release property and cytotoxicity of Periplaneta americana extract-loaded spider fibroin membrane / 中国药房

OBJECTIVE To prepare spider fibroin membrane loaded with Periplaneta americana extract， and investigate its characterization， in vitro drug release property and cytotoxicity. METHODS Using natural spider silk collected from Chilobrachys guangxiensis as raw material， P. americana extract as model drug， the drug-loaded spider fibroin membrane （hereinafter referred to as drug-loaded membrane） was prepared by solvent casting method. The material matrix spider fibroin membrane without P. americana extract （hereinafter referred to as blank membrane） was prepared with same method. The membrane structure was characterized by static water contact angle， Fourier infrared chromatography， X-ray diffraction and scanning electron microscopy from different angles； drug release characteristics in artificial saliva were simulated in vitro to evaluate the drug sustained-release performance. MTT assay was adopted to validate the cytotoxicity of drug-loaded membrane. RESULTS The drug-loaded membrane was prepared， and the static water contact angle was less than 90°， which was less than that of blank membrane. The drug-loaded membrane showed the characteristic absorption peak to polypeptide of P. americana extract at 1 500-1 700 cm－1. X-ray diffraction and scanning electron microscopy also proved that the drug was successfully loaded into the pellicle. The release time of the pellicle in artificial saliva was more than 200 min. The MTT test results showed that the cell proliferation rates of blank membrane and drug-loaded membrane were 84.6% and 79.4% （both greater than 70%）， respectively， without significant potential cytotoxicity. CONCLUSIONS Drug-loaded membrane prepared with natural spider silk has a certain sustained-release effect in artificial saliva， which can be further developed as a drug sustained-release carrier with excellent biological characteristics and biocompatibility.

Esculent coating of spider silk enhanced the preservation and shelf life of apricot / A cobertura escamada de seda de aranha aumentou a preservação e a vida útil do damasco

Abstract According to the Food and Agriculture Organization (FAO), roughly one-third of the total food produced is lost globally. The major cause of this wastage is the perishability of fruits and vegetables. Therefore, researchers have endeavored to develop an effective preservation technique. Our study explored the potential application of spider silk as an odourless and edible preservative coating for fruits. The spider silk was collected from spiders reared in the laboratory, following by degumming and dissolution to formulate the silk solution. For this study, apricots were selected as the model fruit. The apricots were dip coated with the formulated silk solution and allowed to dry. In order to enhance the beta sheet content of the silk coating, the fruits were exposed to water annealing for varying intervals of time under vacuum condition. The effect of silk coating and water annealing time period on preservation of fruits was then evaluated morphologically and gravimetrically. The results showed that the fruits, which were used as control, exhibited a greater degree of water loss and suffered from fungal attack. In contrast, the silk coated fruits showed less water loss and were protected from fungal attack. Therefore, the study provides compelling evidence regarding the application of spider silk as a preservative coating.

Resumo Segundo a Organização para Alimentação e Agricultura (FAO), cerca de um terço do total de alimentos produzidos é perdido globalmente. A principal causa deste desperdício é a perecibilidade das frutas e legumes. Portanto, os pesquisadores têm se esforçado para desenvolver uma técnica de preservação eficaz. Nosso estudo explorou a potencial aplicação de seda de aranha como um revestimento conservante inodoro e comestível para frutas. A seda da aranha foi coletada de aranhas criadas em laboratório, seguindo-se a degomagem e dissolução para formular a solução de seda. Para este estudo, os damascos foram selecionados como fruto modelo. Os damascos foram revestidos por imersão com a solução de seda formulada e deixados secar. A fim de aumentar o teor de folhas beta do revestimento de seda, os frutos foram expostos a recozimento de água durante vários intervalos de tempo sob condições de vácuo. O efeito do tempo de recobrimento de seda e recozimento de água na preservação de frutos foi então avaliado morfologicamente e gravimetricamente. Os resultados mostraram que os frutos, utilizados como controle, apresentaram maior grau de perda de água e sofreram ataque fúngico. Em contraste, os frutos revestidos de seda mostraram menos perda de água e foram protegidos contra ataques fúngicos. Portanto, o estudo fornece evidências convincentes sobre a aplicação de seda de aranha como um revestimento conservante.

Esculent coating of spider silk enhanced the preservation and shelf life of apricot

Abstract According to the Food and Agriculture Organization (FAO), roughly one-third of the total food produced is lost globally. The major cause of this wastage is the perishability of fruits and vegetables. Therefore, researchers have endeavored to develop an effective preservation technique. Our study explored the potential application of spider silk as an odourless and edible preservative coating for fruits. The spider silk was collected from spiders reared in the laboratory, following by degumming and dissolution to formulate the silk solution. For this study, apricots were selected as the model fruit. The apricots were dip coated with the formulated silk solution and allowed to dry. In order to enhance the beta sheet content of the silk coating, the fruits were exposed to water annealing for varying intervals of time under vacuum condition. The effect of silk coating and water annealing time period on preservation of fruits was then evaluated morphologically and gravimetrically. The results showed that the fruits, which were used as control, exhibited a greater degree of water loss and suffered from fungal attack. In contrast, the silk coated fruits showed less water loss and were protected from fungal attack. Therefore, the study provides compelling evidence regarding the application of spider silk as a preservative coating.

Resumo Segundo a Organização para Alimentação e Agricultura (FAO), cerca de um terço do total de alimentos produzidos é perdido globalmente. A principal causa deste desperdício é a perecibilidade das frutas e legumes. Portanto, os pesquisadores têm se esforçado para desenvolver uma técnica de preservação eficaz. Nosso estudo explorou a potencial aplicação de seda de aranha como um revestimento conservante inodoro e comestível para frutas. A seda da aranha foi coletada de aranhas criadas em laboratório, seguindo-se a degomagem e dissolução para formular a solução de seda. Para este estudo, os damascos foram selecionados como fruto modelo. Os damascos foram revestidos por imersão com a solução de seda formulada e deixados secar. A fim de aumentar o teor de folhas beta do revestimento de seda, os frutos foram expostos a recozimento de água durante vários intervalos de tempo sob condições de vácuo. O efeito do tempo de recobrimento de seda e recozimento de água na preservação de frutos foi então avaliado morfologicamente e gravimetricamente. Os resultados mostraram que os frutos, utilizados como controle, apresentaram maior grau de perda de água e sofreram ataque fúngico. Em contraste, os frutos revestidos de seda mostraram menos perda de água e foram protegidos contra ataques fúngicos. Portanto, o estudo fornece evidências convincentes sobre a aplicação de seda de aranha como um revestimento conservante.

Construction of spider silk functional platform via intein trans-splicing / 生物工程学报

To provide technical support for spider silk functional modification, we developed a simple and efficient functional platform via intein trans-splicing. Small ubiquitin-related modifier protein (SUMO) was fused to the recombinant spider silk protein (W2CT) by peptide bond via S0 split intein Ssp DnaB trans-splicing, resulting in a protein SUMOW2CT. However, incorporation of exogenous protein led to mechanical property defect and lower fiber yield, and also slowed down the fiber assembly velocity but no obvious differences in supercontraction and chemical resistance when compared with fibers from W2CT (W). SUMO protease digestion showed positive results on the fibers, indicating that the SUMO protein kept its native conformation and bioactive. Above all, this work provides a technical support for spider silk high simply and efficient functionalized modification.

Preparation of bilayer spider silk protein vascular scaffold and its biomechanical properties and cell compatibility / 医用生物力学

Objective To prepare a bilayer spider silk protein vascular scaffold using electrospinning, observe microstructure of the vascular scaffold and study its biomechanical properties and cell compatibility. Methods Spinning solution was electrospun to prepare (pNSR16/PCL/CS)/(pNSR16/PCL/Gt) bilayer spider silk protein vascular scaffold using rotating receiving rod as the collection device. The effects of mass fraction and wall thickness on the porosity, bursting strength, tensile properties, suture retention strength and water permeability of the vascular scaffold were investigated, and cytotoxicity and cell adhesion property of the vascular scaffold were tested. Results The vascular scaffold presented three-dimensional porous microstructure with randomly distributed fibers. The bursting strength, tensile strength and suture retention strength were directly proportional to mass fraction and wall thickness, but the porosity, water permeability and elongation at break were inversely proportional to mass fraction and wall thickness. The bursting strength range of vascular scaffold was 43~183 kPa, which was higher than the physiological blood pressure; the suture strength was above 0.19 N, which was consistent with the transplantation requirement in vivo; the tensile strength was higher than that of human radial artery, which met the transplantation requirement in vivo; the range of water permeability was 0.3~0.6 mL•min-1•cm-2. The vascular scaffold had no cytotoxicity and facilitated the adhesion and proliferation of endothelial cells. Conclusions It is feasible to prepare the bilayer spider silk protein vascular scaffold through electrospinning. The superior biomechanical properties and biocompatibility properties show that the bilayer spider silk protein vascular can be used for construction of the tissue engineered blood vessels in vitro, with prospect for further vascular graft study, which lays a foundation for its clinical application.

Structure, composition and mechanical properties of the silk fibres of the egg case of the Joro spider, Nephila clavata (Araneae, Nephilidae).

The silk egg case and orb web of spiders are elaborate structures that are assembled from a number of components. We analysed the structure, the amino acid and fibre compositions, and the tensile properties of the silk fibres of the egg case of Nephila clavata. SEM shows that the outer and inner covers of the egg case consist of thick, medium and thin silk fibres. The silk fibres of the outer cover of the egg case are probably produced by the major and minor ampullate glands. The silk fibres of the inner cover of the egg case from cylindrical glands appears to be distinct from the silk fibres of the major ampullate glands based on their micro-morphology, mole percent amino acid composition and types, and tensile behaviour and properties. Collectively, our investigations show that N. clavata uses silk fibres from relatively few glands in varying combinations to achieve different physical and chemical properties (e.g., color, diameter, morphology and amino acid composition) and functional and mechanical properties in the different layers of the egg case.

Optimization of Fermentation Medium with Lactose as an Inducer for High Molecular Weight Recombinant Spider Silk Protein / 中国生物工程杂志

Based on M9 culture medium,the concentration of ingredients of culture medium was optimized for the fermentation of pNSR32/BL21(DE3),the engineering bacterial with spider silk protein,and lactose as an inducer.The condition of optimum culture medium was obtained for the expression of the high molecular weight recombinant spider silk protein by using orthogonal and individual factor experimental design.The result was showed that the optimum culture medium was consisted of 0.3% glycerol,3% yeast,0.75% tryptone,0.05%(NH_4)_2SO_4 and a little inorganic salt_.It was confirmed that the optimum culture medium will benefit the growth of bacterial and expression of recombinant spider silk protein.The production level of propose protein will attain at 20% of the total proteins in the fermentation.