Performance measurement of sericin-coated silks during aging

Silks are among the most precious ancient and historic artefacts worldwide. While washing removes the natural gum from the fibres during the fabrication of most silk textiles, for a small proportion of historic silks some or perhaps all of the sericin still remains. This paper investigated the effect of sericin coating on the aging of silk fibroin by means of ATR and tensile testing. The results show that sericin can provide some extent of protection from light and heat aging. However, in high humidity envi...     

蚕丝蒸汽闪爆改性后的形态结构研究

采用蒸汽闪爆技术对蚕丝进行物理改性 ,利用扫描电镜、红外光谱、X射线衍射、热分析等现代分析方法对处理前后的蚕丝进行形态结构表征 ,结果表明经蒸汽闪爆处理后 ,蚕丝表面形态 ,结晶结构 ,溶解性能有较大的改变 ,蚕丝的化学反应性能有了一定的改善 .     

A precise self-built secondary mass database for identifying red dyes and dyeing techniques with UPLC-MS/MS

Dyes on ancient silks have been a worth studying field through human's history, although current reports ignore the connection between natural dyes origin and relevant colour reduction methods, which poses an insurmountable obstacle for restoration of historical silks. In this paper, a series of 12 red hue silks from six natural dyes (sappanwood, Chinese madder, safflower, lac, cochineal, dragon's blood) via three different dyeing techniques were used to establish a self-built precise tandem mass spectrometry (MS/MS) database. With organic solvent extracting on those manual-dyed silks, ultraperformance liquid chromatography - electrospray ionization - quadrupole time of flight mass spectrometry (UPLC-ESI-QTOF-MS) was utilized to form preliminary MS database for screening and identifying of the potential dyes compounds without standard references. Furthermore, combining the targeted MS/MS mode and the matching threshold of 70.00, a self-built secondary MS/MS database was successfully established, which contains 33 compounds, 32 chromatograms and 32 MS/MS fragments. As for real sample application, the self-built precise MS/MS database had revealed that the dyes on two historical silks (Shanghai Museum, China) belong to Chinese madder just with different mordant dyeing ordinal. Additionally, by experimental restoration, visually indistinguishable silks (ΔE_ab* < 1.5 NBS) were successfully restored. This explorative methodology can further inspire the traceability of biological dyestuffs, which lays instructive foundation on protection and restoration of artefacts, connecting the archaeological science and human art.     

In Vivo Characterizations of the Immune Properties of Sericin: An Ancient Material with Emerging Value in Biomedical Applications

The biosafety of sericin remains controversial. The misunderstanding regarding sericin causing adverse biological responses have been clarified by extensively reviewing relevant literatures and experimentally demonstrating that sericin exhibits mild inflammatory responses, negligible allergenicity, and low immunogenicity in vivo. This study supports that sericin is biosafe as a natural biomaterial.     

Treatment of silk production wastewaters by membrane processes for sericin recovery

Sericin protein, although a valuable resource for many industries including cosmetics, pharmaceutical and biomedical, has been discarded as a waste in silk industry, causing environmental pollution. This paper describes determination of a membrane-based process for sericin recovery from cocoon cooking wastewaters (CCW) that will enable value-added utilization of waste sericin. The iso-electric point (pI) of sericin was found as 5–6, whose MW was distributed as 180–200, 70–80, 30–40 and 10–25 kDa. Prior to membrane filtration, sericin was separated from other impurities via centrifugation (CFG) followed by microfiltration (MF) in the pre-treatment stage, which also helped minimize post membrane fouling. Ultrafiltration (UF) and nanofiltration (NF) were adopted at a pH equal to pI of sericin. UF achieved partial recovery of sericin polypeptides at 37–60%, which was attributed to increased transmission of uncharged sericin polypeptides at their pI. On the other hand, NF achieved sericin recovery as high as 94–95%, containing all MW fractions. Severe flux decline was the major problem due to protein–membrane interactions and high sericin concentrations, where concentration polarization mainly had a dominant effect. Although flux declines were as high as 58–88% in UF and 70–75% in NF, flux recovery by at least 83% was achieved by chemical cleaning using NaOH and free chlorine.     

The discovery of free radicals in ancient silk textiles

Protection of ancient silk textiles from further deterioration is of vital importance to the investigation and preservation of ancient Chinese culture. Ancient silk textiles from several different ages (more than 2000 years ago) and regions were studied by means of Raman and electron paramagnetic resonance (EPR) spectroscopy in an attempt to unveil the deterioration mechanism of silk. The Raman spectra showed two peaks (D and G), which are indicative of carbonization. The EPR spectra of the ancient samples showed a characteristic sharp absorption centered at g∼2.0037 without a hyperfine structure, and have been identified as those of carbon radicals. These free radicals had not been discovered in ancient silk fabrics before, and the discovery may shed light on the deterioration mechanisms of ancient silk textiles.     

Oriented nucleation of hydroxylapatite crystals on spider dragline silks

Spider dragline silk as a protein fiber can be pictured as the oriented organization of protein nanocrystals along the long axis with their spacing filled by amorphous protein domains. We used the surface of the spider dragline silk as a biological template to nucleate bone mineral hydroxylapatite (HAP) site-specifically from a HAP-supersaturated solution. HAP crystals were found to be nucleated on the surface of silks with their c axis preferentially oriented at an average angle of 72.9 degrees with respect to the long axis of the silks. The preferred orientation is nearly identical among the different mineralized silks that we studied. Other materials such as Au and CdS could be nucleated on the silks but did not show any preferred orientation. We believe that the oriented nucleation of HAP is directly related to the structures of silks and HAP. The mineralized silks will combine the good mechanical properties of the spider silks and the biocompatibility of HAP and may be assembled into ideal biomaterials as bone implants.     

苯乙烯在蚕丝丝胶上接枝共聚的研究

<正> 蚕丝丝胶(Silk Sercin简写SS)是由十八种氨基酸缩合而成的天然旦白,占蚕茧重量的20—30％,由于它溶于水,在缫丝过程中随废水而流失。我们曾对丝胶-金属络合物的制备及其对DL和L-3,4二羟基苯丙氨酸氧化催化活性进行了研究。本文研究了苯乙烯(St)在丝胶上接枝共聚的机理及规律,用红外光谱、差示扫描量热法、热重     

Voltammetric determination of sericin based on its interaction with carmine

A simple yet sensitive method is developed for the determination of sericin using voltammetry based on the interaction between sericin and carmine for the first time. In the absence of sericin, carmine has a pair of well-defined redox peaks in a pH 1.81 Britton-Robinson buffer solution. Although no new redox peaks appear upon the addition of sericin into a carmine solution, the peak currents of the old peaks reduce while the peak potentials shift positively. This observation is attributed to the decrease in the diffusion coefficient and electrode reaction rate constant of carmine in the presence of sericin. A binding mechanism is proposed and discussed, and the binding constant and binding ratio are calculated as 2.32 × 10⁶ L mol⁻¹ and 1:1, respectively. Furthermore, the decrease in the peak currents is found proportional to the sericin concentration in the range of 32.0-800.0 μg mL⁻¹ with a detection limit of 13.52 μg mL⁻¹. The method is further applied to the determination of sericin in degumming wastewater with satisfied average recoveries from 96.7 to 103.3%. The results are in good agreement with those obtained by the conventional Coomassie brilliant blue G-250 spectrophotometric method.     

基于动物丝蛋白的人工纺丝

动物丝,特别是蜘蛛丝近年来由于其优异的综合力学性能而备受关注。但是天然动物丝的应用由于种种原因而受到各种限制,因此人们期望通过人工纺丝获得性能与天然动物丝相近的人工丝纤维。本文就采用动物丝蛋白进行人工纺丝的历史和现状,从再生蜘蛛丝蛋白、重组蜘蛛丝蛋白和再生蚕丝蛋白等方面进行综述,比较了天然动物丝和人工丝纤维的力学性能,并且探讨了人工生物模拟纺丝制备高性能人工丝纤维(超级纤维)的前景。     

Inhibitory effects of silk protein, sericin on UVB-induced acute damage and tumor promotion by reducing oxidative stress in the skin of hairless mouse

This study was conducted to assess protective effect of an antioxidant protein, sericin, on UVB-induced acute damage and tumor promotion in mouse skin. In experiment 1, HR-1 hairless mice were treated with 180 mJ/cm2 of ultraviolet B light (UVB) once daily for 1 and 7 days. The treatment for 7 days caused red sunburn lesions of the skin. The intensity of red color and area of these lesions were inhibited by the topical application of sericin at the dose of 5 mg after UVB treatment. Immunohistochemical analyses showed that the application of sericin significantly suppressed UVB-induced elevations in 4-hydroxynonenal (4-HNE), expression of cyclooxygenase-2 (COX-2) protein, and proliferating cell nuclear antigen (PCNA)-labeling index in the UVB-exposed epidermis. In experiment 2, HR-1 hairless mice were treated with 200 nmol of 7,12-dimethylbenz [alpha] anthracene (DMBA) followed 1 week later by irradiation with 180 mJ/ cm2 of UVB twice weekly for 22 weeks. The protective effect of sericin was evident in terms of significant reduction in tumor incidence and tumor multiplicity at the dose of 5 mg. The results suggest that sericin possesses photoprotective effect against UVB-induced acute damage and tumor promotion by reducing oxidative stress, COX-2 and cell proliferation in mouse skin.     

Anatase—a pigment in ancient artwork or a modern usurper?

Fragments of wall-paintings from Roman villas in Easton Maudit, which date from ca 150 AD have been studied by Raman spectroscopy. An intact ancient Roman paint pot discovered in the remains of a villa in Castor, Cambridgeshire, still containing a mixture of white and red pigment was also analysed and the pigments identified as haematite and anatase. The discovery of anatase in the intact artist’s paint pot, particularly, and also on fragments of broken paint pots from the Easton Maudit villa site, is a unique contribution to current knowledge of ancient European pigment history, because the presence of this mineral has not hitherto been recognised fully in an ancient artist’s palette. The relative spectral response of anatase and haematite in the Raman data is compared with that of anatase and other red pigments such as minium, cinnabar, and litharge.     

Surface pressure‐area curves compression isotherm of sericin Langmuir monolayer

The Langmuir monolayer of sericin protein was studied by means of surface pressure (π)—molecular area (A) isotherms at different pH subphase. The monolayer of sericin exhibits typical phase transition phenomena at pH 2, pH 4.8, pH 7 and pH 11, respectively, including from gas state to gas‐liquid state and finally to condensed solid state. However, the monolayer of sericin on pH 11 subphase appears to be solid state. Copyright © 2007 John Wiley & Sons, Ltd.     

The Influence of Silkworm Species on Cellular Interactions with Novel PVA/Silk Sericin Hydrogels

Sericin peptides and PVA are chemically modified with methacrylate groups to produce a covalent PVA/sericin hydrogel. Preservation of the sericin bioactivity following methacrylation is confirmed, and PVA/sericin hydrogels are fabricated for both B. mori and A. mylitta sericin. Cell adhesion studies confirm the preservation of sericin bioactivity post incorporation in PVA gels. PVA/A. mylitta gels are observed to facilitate cell adhesion to a significantly greater degree than PVA/B. mori gels. Overall, the incorporation of sericin does not alter the physical properties of the PVA hydrogels but does result in significantly improved cellular interaction, particularly from A. mylitta gels.

     

Ancient biodeterioration: an FT–Raman spectroscopic study of mammoth and elephant ivory

Raman spectra of mammoth ivory specimens have been recorded using near-infrared excitation, and comparisons made with modern Asian and African elephant ivories. Whereas the most ancient mammoth ivory (60–65 ky) showed no evidence for an organic collagen component, more recent samples of mammoth ivory indicated that some preservation had occurred, although with biodeterioration of the protein structure exhibited by the amide I and III bands in the 1200–1700 cm⁻¹ region of the Raman spectrum. The consequent difficulties encountered when applying chemometrics methods to ancient ivory analysis (which are successful for modern specimens) are noted. In the most ancient mammoth ivory specimens, which are extensively fragmented, evidence of mineralization is seen, with the production of gypsum, calcite and limonite; Raman microscopic analysis of crystalline material inside the fissures of the mammoth ivory shows the presence of gypsum as well as cyanobacterial colonisation. The application of Raman spectroscopy to the nondestructive analysis of archaeological materials in order to gain information of relevance to their preservation or restoration is highlighted.     

陶寺、尉迟寺白灰面的测试研究

在XRD和拉曼光谱分析的基础上,借助XRF、ICP-AES和ICP-MS技术,对取自陶寺、尉迟寺遗址的“白灰面”做了相关测试和研究。结果表明,尉迟寺F85号红烧土房墙体表面白灰面为碳酸钙。陶寺“白灰面”有两种,一种为人工烧制的石灰,系石灰石烧制而成,表面打磨得较为光滑,并且有一块样品分4次加工,分为4层,表层主要为方解石和文石,里层则为石英含量略高的粘土和石灰的混合物,具较高的工艺,另外,有一块“白灰面”经检测为二水硫酸钙,这首次表明我国古代先民在4千年前已经开始开采和使用石膏做为建筑材料。     

丝胶-甲基丙烯酸甲酯接枝共聚物的合成与表征

在酸性水介质中,以硝酸铈铵为引发剂合成了丝胶-甲基丙烯酸甲酯接枝共聚物,其结构经1H NMR,IR,SEM和GPC表征。用正交试验法考察了各因素对接枝共聚反应的影响,结果表明,单体浓度对接枝聚合反应的影响最大,反应时间的影响最小。     

丝胶蛋白质与铜(Ⅱ)的配位反应

本文运用pH滴定、光谱法、电子自旋波谱、X射线衍射研究丝胶蛋白质与铜 (Ⅱ )的配位反应及其络合物的高次结构 .当溶液的 pH >9 1时 ,丝胶蛋白质与Cu(Ⅱ )生成了稳定的络合物 ,此络合物具有拉伸八面体Cu(N) 4(OH-) 2 型配位结构 ,高次结构为无规卷曲非晶结构 .     

蜘蛛与蚕的人工强制纺丝研究进展

为制备高性能人造蜘蛛丝和蚕丝,人们在蜘蛛丝蛋白的基因重组、再生蜘蛛丝蛋白或蚕丝蛋白的仿生纺丝,以及蜘蛛与蚕的人工强制纺丝方面开展了大量工作.研究了人工强制纺丝,比较了蜘蛛牵引丝和蚕丝在不同纺丝条件下的力学性能.结果表明:在一定范围内增加纺丝速率有利于提高蜘蛛丝和蚕丝的力学性能,此外,环境温度、纺丝状态等条件对丝的性能也...     

A transparent sericin-polyacrylamide interpenetrating network hydrogel as visualized dressing material

High transparent and biocompatible hydrogel dressing with bioactivity is attractive for clinical skin repair. Here we report a high optically transparent interpenetrating network (IPN) hydrogel that was fabricated by sericin and polyacrylamide. The hydrogels possess pH-dependent degradation as well as high porosity and porous structures with different sized diameters and distribution. Moreover, the swelling behaviors, degradation dynamics, and mechanical strength can be flexibly regulated by adjusting the content of sericin. In addition, the hydrogel system is compatible with hosting cells owing to its excellent cell-adhesive capability, effectively promoting cell attachment, proliferation and long-term survival. Together, our study demonstrates that the sericin-polyacrylamide interpenetrating network hydrogel may serve as a visualized dressing material for real-time monitoring of wounds.