紫外交联改性丝素蛋白的制备及溶胀性能测试

本文采用紫外交联法制备丝素和2-(二甲氨基)丙烯酸乙酯(DMAEA)、丝素和2-羟基乙基丙烯酸酯(HEA)及丝素和季铵盐的改性丝素蛋白凝胶。通过溶胀率、红外光谱表征改性丝素蛋白凝胶的结构特性,通过热重分析研究改性丝素蛋白凝胶的热稳定性。实验结果表明DMAEA改性丝素蛋白凝胶的溶胀性能优于添加HEA和季铵盐的改性丝素蛋白凝胶;盐浓度的影响表明,DMAEA、HEA和季铵盐的改性丝素蛋白凝胶溶胀率均随盐浓度升高而下降。热重分析研究表明,三种紫外聚合的凝胶,在100℃附近开始分解,450℃左右分解完,热稳定较好。三种改性方法中,添加HEA的凝胶的热稳定较好,添加DMAEA的凝胶溶胀率最好。     

可溶性丝素蛋白新型脱盐工艺研究

天然丝素蛋白不溶于水,溶于强酸、强碱和一些中性盐溶液,为获得高纯度的可溶性丝素蛋白,脱盐是关键环节。将丝素蛋白经脱胶后溶解于氯化钙-乙醇-水三元体系溶液制成可溶性丝素蛋白,用扩散渗析和电渗析2种集成膜过程进行脱盐。该工艺较传统的透析袋脱盐方法,具有耗时短、脱盐率高等特点,脱盐率可达99.98%以上,回收率可达90.1%。     

不同溶剂下丝素蛋白膜对药物缓释的影响

分别以LiBr溶液和离子液体为溶剂制备的丝素蛋白膜为载体,利用双膜夹心法将待测的药物包裹在丝素蛋白膜内,然后对目标药物Vc进行缓释研究。结果表明:以离子液体为溶剂制备的丝素蛋白膜结构致密,分子间隙较小,当pH=2.5,释药时间在100min,释药率达到最大,约为79%,释药效果较传统膜好,其优良的性能扩大了在药物缓释上的应用。     

丝素蛋白复合膜材料及其应用研究进展

介绍了丝素蛋白与天然大分子、碳纳米材料、合成聚合物、纳米金属及金属氧化物等材料复合制备丝素蛋白复合膜的方法、性能，总结和分析了丝素蛋白复合膜在生物医药、光电领域和化工分离方面的应用。在此基础上，指出了未来丝素蛋白复合膜的进一步应用研究方向，除了继续在生物医药领域的应用之外，丝素蛋白复合膜材料在光电领域具有很大潜力，同时未来在化工分离领域也有很好的发展前景。     

丝素蛋白-纳米银复合材料在抗菌领域的研究进展

重点总结归纳了丝素蛋白-纳米银复合膜、水凝胶、纤维等多种应用形态在抗菌领域的最新研究进展,阐述了丝素蛋白与纳米银结合的抗菌优势、复合材料目前尚待解决的稳定性与安全性问题,展望了丝素蛋白-纳米银复合材料发展方向。     

离子液体对丝素蛋白溶解性能的影响

合成了一系列碱性离子液体,其中离子液体1-丁基-3-甲基咪唑乙酸盐([Bmim]AC)对丝素蛋白具有良好的溶解性能。考察了丝素蛋白在该离子液体中的溶解特性及在离子液体中的溶解温度和溶解时间,结果表明,在75℃下,溶解840 min,该离子液体对丝素蛋白的溶解能力达到15%(质量分数)。XRD和FTIR分析表明,再生丝素蛋白的构象以α-螺旋为主,丝素蛋白在溶解过程中没有发生衍生化。因此,[Bmim]AC离子液体是丝素蛋白的优良溶剂。     

丝素蛋白改性聚氨酯膜的研制

用预聚体接枝 -扩链法制备了丝素蛋白改性聚氨酯膜 ,考察了反应温度、时间和湿度等因素对膜的力学性能的影响。结果表明改性聚氨酯膜具有良好的柔韧性 ,其力学性能明显优于纯丝素膜。     

不溶性丝素薄膜制备新方法

天然丝素蛋白具有良好的生物相溶性,是一种具有广阔应用前景的生物材料,可用于酶固化、人造皮肤、人造韧带以及组织工程等各个方面。如果将丝素应用于生物材料,需要将蚕丝溶解后再制备成薄膜、管状等形状。而当丝素蛋白溶解在特定溶液中再干燥制备成各种形状后,却变得易溶于水,从而失去其在生物材料领域的应用价值。     

蚕丝蛋白在生物样本保存领域应用的研究进展

蚕丝是一种天然的高分子材料,由60%~80%的丝素、15%~35%的丝胶及约5%的石蜡、色素、糖类等杂质组成。丝素具有良好的生物相容性和降解性,在药物缓释、促进伤口愈合、组织工程支架等生物医药领域及降血糖、抑菌等医疗保健方面均具有广泛应用;丝胶包裹在丝素纤维外层,对丝素起保护作用,其不仅是非常有用的生物材料,还具有许多生物活性和药理作用,如抗氧化性、抗肿瘤活性、物理胃肠功能等作用。近年,蚕丝蛋白在生物样本保存领域的应用备受研究者关注,本文对蚕丝蛋白在生物样本低温保存和常温保存方面的应用和成果、存在的问题及未来的研究方向作一综述,以期为蚕丝蛋白在生物样本保存领域的应用提供参考。     

蚕丝素蛋白及其应用

阐述了丝素蛋白的组成、结构、性质和制备方法 ,及其综合利用现状。丝素作为一种天然蛋白质在医学和食品等行业中的应用开发研究具有深远的意义。     

SF煤/聚苯胺导电复合材料结构表征

采用FTIR，X衍射和SEM等分析测试手段对在位聚合法制得的SF煤／聚苯胺导电复合材料的官能团结构、结晶性、外观形貌以及煤与聚苯胺之间的化学作用进行了分析，SEM分析发现，SF煤／聚苯胺复合物颗粒外型与SF煤相似，这表明聚苯胺是以SF煤为模板聚合的；FTIR分析表明，苯胺在聚合过程中和SF煤发生了化学作用，形成了更大的共轭体系；X衍射分析表明，苯胺在煤中聚合生成了较多低聚合度的聚苯胺晶粒，这些晶粒与SF煤发生了较为稳定的复合。     

Silk fibroin membranes with self-assembled globular structures for controlled drug release

In this paper, we have evaluated the incorporation of a drug model and its release from silk fibroin (SF) membranes, analyzing the morphological, chemical, barrier, and biological properties. SF self-assembled into stable globular structures, encapsulating the drug, when diclofenac sodium (DS) was incorporated into SF solution prior to membranes preparation. The membranes showed biostatic action and prevented microorganism permeation. Kinetic studies indicate that DS was released in 120 min, with Fickian diffusion as the main mechanism of release. Results of this paper emphasize the potential of SF in wound healing, with good barrier and biological properties. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48763.     

Effects of Pressure from High-Pressure Homogenization on the Performance of Soybean Flour Based-Adhesive

A green and sustainable soybean flour (SF) adhesive is considered as a potential alternative to toxic formaldehyde-based resins. Nevertheless, poor bond stability and low bonding strength is caused by the uneven size distribution and low reactivity of SF. Herein, SF adhesives with excellent and stable performance are synthesized via the synergistic action of high-pressure homogenization (HPH) treatment by incorporating a green crosslinker. Specifically, an even distribution of the SF particles is obtained after the HPH treatment, from which large soy protein molecules are broken to several small and even single protein molecules. In this way, the adhesion stability is improved. Additionally, more active groups buried in proteins are exposed after the HPH treatment due to the unfolding of the protein molecules. Therefore, a more reactive SF is obtained and thus forms a denser crosslinking structure of resultant the adhesive, providing an increase in bonding strength. Particularly, the effects of homogenizing pressure on the adhesive performance are investigated. The results show that a 215.6% increase of wet bonding strength (1.01 MPa) is obtained after the HPH treatment with a homogenizing pressure of 20 MPa, meeting the standards (GB/T 9846-2015) for interior applications.     

Modulating properties of chemically crosslinked PEG hydrogels via physical entrapment of silk fibroin

A variety of polymers of synthetic origins (e.g., poly(ethylene glycol) or PEG) and macromolecules derived from natural resources (e.g., silk fibroin or SF) have been explored as the backbone materials for hydrogel crosslinking. Purely synthetic PEG‐based hydrogels are often chemically crosslinked to possess limited degradability, unless labile motifs are designed and integrated into the otherwise non‐degradable macromers. On the other hand, SF produced by Bombyx mori silkworm can be easily formulated into physical hydrogels. These physical gels, however, are less stable than the chemically crosslinked gels. Here, we present a simple strategy to prepare hybrid PEG‐SF hydrogels with chemically crosslinked PEG network and physically entrapped SF. Visible light irradiation initiated rapid thiol‐acrylate gelation to produce a network composed of non‐degradable poly(acrylate‐co‐NVP) chains, hydrolytically labile thioether ester bonds, and interpenetrating SF fibrils. We evaluated the effect of SF entrapment on the crosslinking efficiency and hydrolytic degradation of thiol‐acrylate PEG hydrogels. We further examined the effect of adding soluble SF or sonicated SF (S‐SF) on physical gelation of the hybrid materials. The impacts of SF or S‐SF inclusion on the properties of chemically crosslinked hybrid hydrogels were also studied, including gel points, gel fraction, equilibrium swelling ratio, and mesh size. We also quantified the fraction of SF retention in PEG hydrogels, as well as the influence of remaining SF on moduli and degradation of chemically crosslinked thiol‐acrylate PEG hydrogels. This simple hybrid hydrogel fabrication strategy should be highly useful in future drug delivery and tissue engineering applications. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43075.     

Water-annealing treatment for edible silk fibroin coatings from fibrous waste

Silk fibroin (SF) is an engineered biopolymer with properties that are desirable for the development of food preservation materials, such as edible coatings or packaging. In this study, SF from fibrous waste was assessed for the first time as an edible coating for strawberries. Relationships were established between the structural properties of SF thin films obtained from silk waste, both untreated (SFW) and water annealed (WA-SFW) and their morphology and performance as edible strawberry coatings. According to the results obtained, the water-annealing treatment led to a structural modification in SF films. The strawberries coated with WA-SFW exhibited better performance during storage by reducing weight loss and preserving its visual appearance. The analysis of metal contaminants showed that SFs obtained from fibrous waste are relatively nontoxic. Therefore, using this raw material for the development of edible coatings in perishable fruits is considered promising. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48505.     

Glycerin and ethanol as additives on silk fibroin films: Insoluble and malleable films

Silk fibroin (SF) films have been largely studied as biomaterials due to their biocompatibility and biodegradability. Casting a SF aqueous solution at room temperature is a common technique to produce SF films at relative low cost and processing time; however, their brittleness and solubility in water make them unsuitable for certain biomedical applications. In this study, the incorporation of additives, ethanol and glycerin, are presented as an alternative to both improve mechanical properties of SF films and decrease their solubility in water. SF films with additives were further characterized using scanning electron microscopy, X‐ray diffraction, Fourier transformed infrared spectroscopy with attenuated total reflection, analysis of water solubility, mechanical test of traction, and in vitro cytotoxicity experiments. The results show that SF films containing additives are stable in water due to the effect of glycerin and ethanol, and do not require post‐treatments. Furthermore, great improvements on elongation of the films were achieved, mainly in the presence of both additives. In addition, all films were not toxic to cells, which is a first indication of their biocompatibility. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Fabrication and characterization of silk fibroin/poly(ethylene glycol)/cellulose nanowhisker composite films

The flexible and transparent composite films were fabricated by a mixture of silk fibroin (SF), poly(ethylene glycol), and mulberry cellulose nanowhiskers (CNWs). The CNWs were uniformly dispersed in the matrix when its content was as high as 12 w/w%. The tensile properties of composite films generally depended on the nanowhisker content, but significantly improved when compared to the pure SF film. DMA analysis revealed that the alpha transition temperature increased gradually with the increase of nanowhisker content, probably due to the formation of interactions between the nanowhiskers and the SF molecular chains, leading to the mobility reduction of the amorphous SF. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Investigations on the performance of silica fume-incorporated cement pastes and mortars

Studies on the performance of cementitious products with silica fume (SF) are very important, as it is one of the inevitable additives to produce high-performance concrete (HPC). In this study, some experimental investigations on the influence of SF on various preliminary properties of cement pastes and mortars are reported. The properties included specific gravity and normal consistency (NC) of cement and air content and workability of mortar with different SF contents. Pozzolanic and chemical reactions of SF have been studied on setting times, soundness and shrinkage of cement pastes. Further, strength developments in compression and tension in cement mortars have also been studied at various SF contents. SF was varied from 0% to 30% at a constant increment 2.5/5% by weight of cement. Test results show that the SF changes the behavior of cement pastes and mortars significantly. It has been observed that the water-binder (w/b) (cement+SF) ratio seemed to play an important role for the performance of the products with higher SF contents. NC, soundness and drying shrinkage of cement pastes and the strength of mortar increase as the SF content increases, while the initial setting times of cement pastes and the air content and workability of mortar decrease as the SF content increases. However, hardly any influence has been observed on the final setting times of cement pastes. The early age hydration reactions of C₃A and C₃S increase with the addition of SF. The optimum SF content ranges between 15% and 22%.     

Influence of pozzolanic additives on hydration mechanisms of tricalcium silicate

Pozzolanic mineral additives, such as silica fume (SF) and metakaolin (MK), are used to partially replace cement in concrete. This study employs extensive experimentation and simulations to elucidate and contrast the influence of SF and MK on the early age hydration rates of tricalcium silicate (triclinic C₃S), the major phase in cement. Results show that at low replacement levels (i.e., ≤10%), both SF and MK accelerate C₃S hydration rates via the filler effect, that is, enhanced heterogeneous nucleation of the main hydration product (C–S–H: calcium‐silicate‐hydrate) on the extra surfaces provided by the additive. The filler effect of SF is inferior to that of MK because of agglomeration of the fine particles of SF, which causes significant reduction (i.e., up to 97%) in its surface area. At higher replacement levels (i.e., ≥20%), while SF continues to serve as a filler, the propensity of MK to allow nucleation of C–S–H on its surface is substantially suppressed. This reversal in the filler effect of MK is attributed to the abundance of aluminate [Al(OH)₄^?] ions in the solution—released from the dissolution of MK—which inhibit topographical sites for C–S–H nucleation and impede its subsequent growth. Results also show that in the first 24 hours of hydration, MK is a superior pozzolan compared to SF. However, the pozzolanic activities of both SF and MK are limited and, thus, do not produce significant alterations in the early age hydration kinetics of C₃S. Overall, the outcomes of this study provide novel insights into the mechanistic origins of the filler and pozzolanic effects of SF and MK, and their impact on cementitious reaction rates.