Deduction of a facile method to construct Antheraea mylitta silk fibroin/gelatin blend films for prospective biomedical applications

Blend films of two types (I and II) were prepared by mixing Antheraea mylitta silk fibroin (AMF) and gelatin solution in various blend ratios via the solution casting method. Two different crosslinkers, namely glutaraldehyde and genipin, were used during blend preparation. The structural characteristics and thermal properties of the blend films were examined by Fourier transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), Thermogravimetric analysis (TGA) and Diffrential scanning calorimetery (DSC). The FTIR spectra showed conformational alterations in type I blend films while type II films attained high β‐sheet crystallinity. The XRD diffractograms presented a high degree of crystallinity in type II blend films compared to type I, which showed an almost amorphous structure. Further, thermal and biological studies were conducted on type II films. According to the TGA thermograms, the degradation temperature of the crosslinked blend films shifted compared to pure gelatin and pure AMF films. Partial miscibility of the two components was indicated by DSC thermograms of the blends. The high water uptake capacity of type II blend films was found to imitate hydrogel behaviour. The blend films did not show any toxicity in 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl tetrazolium bromide (MTT) assay and supported L929 fibroblast cell spreading and proliferation. The biodegradation of the blend films was significantly faster than the pure silk film. © 2020 Society of Industrial Chemistry     

Regulation effect of osteoblasts towards osteocytes by silk fibroin encapsulation

Herein, the rational design micromilieus involved silk fibroin (SF)-based materials have been used to encapsulate the osteoblasts, forming an extracellular coated shell on the cells, which exhibited the high potential to shift the regulation of osteoblasts to osteocytes by encapsulation cues. SF coating treated cells showed a change in cell morphology from osteoblasts-like to osteocytes-like shape compared with untreated ones. Moreover, the expression of alkaline phosphatase (ALP), collagen I (Col I) and osteocalcin (OCN) further indicated a potential approach for inducing osteoblasts regulation, which typically accelerates calcium deposition and cell calcification, presenting a key role for the SF encapsulation in controlling osteoblasts behavior. This discovery showed that SF-based cell encapsulation could be used for osteoblasts behavior regulation, which offers a great potential to modulate mammalian cells’ phenotype involving alternating surrounding cues.     

Research progress on chemical modification of silk fibroin and its applications北大核心CSCD

Mulberry silk is composed of the two major parts of two triangle-like silk fibroin fibers and sericin covering the fibers and a few lipids. After removing the sericin on the raw silk what is left is the silk fibroin fiber. Silk fibroin is the main part of silk accounting for about 75% of the total weight. Silk fibroin contains 18 natural amino acids such as glycine Gly alanine Ala serine Ser serine aspartic acid Asp and tyrosine Tyr . The secondary structure of silk fibroin has three main conformations α-helix β-fold and random coil. Under certain conditions the three conformations can transform into each other and change the mechanical properties of the silk fibroin material. Silk fibroin extracted from silk fiber is a natural polymer with biocompatibility and biodegradability. It can be further processed into different forms of materials nanoparticles films hydrogels sponges etc. It has been applied in many fields such as biomedicine and cosmetics. In order to meet the needs of different fields researchers have conducted further chemical modification treatment based on the original excellent properties of silk fibroin. Meanwhile the active groups on various amino acid residues in silk fibroin also provide chemical reaction sites for the chemical modification of silk fibroin. The chemical modification methods of silk fibroin mainly include amino acid residue modification macromolecular grafting modification and crosslinking reaction modification. Among them amino acid residue modification can modify protein amino acid residues by chemical reagents and some groups can be introduced into the side chains of silk fibroin macromolecules. Grafting modification of silk fibroin macromolecules is one of the main means to bind functional compounds to silk fibroin macromolecular chains. The properties of grafted silk fibroin are affected by the type and grafting rate of the grafts. The chemical crosslinking reaction modification of silk fibroin macromolecules is to make the macromolecular chains connected by covalent bonds and form a network structure by means of crosslinking agents enzymes or ultraviolet irradiation. The cross-linking reaction can not only form covalent bonds within and between the molecular chains of silk fibroin thus changing its structural properties and improving its stability but be used to form covalent bonds with other polymers. At present the chemical modification of silk fibroin is mainly applied in the fields of silk textiles biomedicine and environmental science. In the field of silk textiles graft copolymerization modification of vinyl and other monomers crosslinking agent modification and other methods are used to overcome the shortcomings of silk like being easy to wrinkle. The graft modified monomers mainly include ethylene methacrylate and methylacrylamide. The active groups on crosslinking agents such as polycarboxylic acid / anhydride and epoxide are covalently combined with carboxyl hydroxyl and amino groups on macromolecules of silk fibroin to improve the wrinkle resistance of silk fabrics. In the field of biomedicine silk fibroin materials with appropriate chemical modification have better biological activity drug delivery ability antimicrobial properties and mechanical properties. The optimization of these properties enables silk fibroin materials to show great potential in drug control delivery tissue regeneration and wound repair. The applied research in the field of environmental science mainly focuses on the adsorption separation and catalysis of impurities in water. Therefore the modification of amino acid residues grafting and cross-linking of protein macromolecules can change some important properties of silk fibroin and meet the requirements of various applications and functionalization of silk fibroin. In many fields of chemical modification and application of silk fibroin protein fruitful results have been achieved which has laid a good foundation for the further development of related fields and also shows that the chemical modification of silk fibroin material has great potential and application prospects. However there are still some problems that need to be overcome and further improved in the current chemical modification methods such as mild modification conditions and accurate adjustment of the degree of modification which will be the research direction of related fields in the future. © 2022 Authors. All rights reserved.     

Silk proteins for biomedical applications: Bioengineering perspectives

Biomaterials of either natural or synthetic origin are used to fabricate implantable devices, as carriers for bioactive molecules or as substrates to facilitate tissue regeneration. For the design of medical devices it is fundamental to use materials characterized by non-immunogenicity, biocompatibility, slow and/or controllable biodegradability, non-toxicity, and structural integrity. The success of biomaterial-derived biodevices tends to be based on the biomimetic architecture of the materials. Recently, proteins from natural precursors that are essentially structural and functional polymers, have gained popularity as biomaterials. The silks produced by silkworms or spiders are of particular interest as versatile protein polymers. These form the basis for diverse biomedical applications that exploit their unique biochemical nature, biocompatibility and high mechanical strength. This review discusses and summarizes the latest advances in the engineering of silk-based biomaterials, focusing specifically on the fabrication of diverse bio-mimetic structures such as films, hydrogels, scaffolds, nanofibers and nanoparticles; their functionalization and potential for biomedical applications.     

甲醇、戊二醛交联剂对丝素蛋白/明胶多孔支架的性能影响

为了对比甲醇、戊二醛两种交联剂对丝素蛋白/明胶复合多孔支架的性能影响,采用冷冻干燥法等比例制备该支架,分两组分别用甲醇和戊二醛进行交联。通过观察支架的微观形貌,测量支架的孔隙率、吸水率、溶胀率,测试热稳定性及力学性能,比较经两种交联剂处理后支架结构和性能的变化。结果表明,经戊二醛交联后的支架孔隙分布更加规则、均匀,孔隙率、吸水率、溶胀率更高,力学性能更强。采用戊二醛交联丝素蛋白/明胶复合多孔支架,能够使支架性能更加优良。     

预处理对构建丝素蛋白纤维/磷灰石仿生骨修复材料的影响

利用氯化钙-乙醇-水(n(CaCl2):n(EtOH):n(H2O)=1:2:8)三元溶液对丝素蛋白纤维预处理,再采用交替浸渍法将其分别浸在钙溶液和磷溶液中交替浸渍、仿生矿化制备丝素蛋白纤维/磷灰石复合材料,采用SEM、FTIR、XRD和TGA等技术研究了不同预处理时间对丝素蛋白纤维微结构和构建丝素蛋白纤维/磷灰石的影...     

Drug Delivery: Bio‐inspired Heterostructured Bead‐on‐String Fibers That Respond to Environmental Wetting (Adv. Funct. Mater. 8/2011)

Inspired by the geometric structure of ecribellate spider capture silk and its spinning characteristics, we propose a one‐step electrohydrodynamic method to fabricate bead‐on‐string heterostructured fibers (BSHFs). By combining electrospinning and electrospraying strategies using a sprayable outer fluid with low viscosity and a spinnable inner fluid with high viscosity in a coaxial jetting process, hydrophilic poly(ethylene glycol) beads are successfully imprinted on a hydrophobic polystyrene string. It is demonstrated that the BSHFs are capable of intelligently responding to environmental change. With a change in relative humidity, the fibers show a segmented swelling and shrinking behavior in the “bead” parts whereas the “string” parts remain the same. The elastic BSHFs with alternating hydrophilic and hydrophobic surface characteristics represent a type of mesoscale analogues that block copolymers and may bring about new properties and applications. Moreover, the combined electrohydrodynamic approach developed herein should open new routes to multifunctional one‐dimensional heterostructured materials.