Robust Waterborne Polyurethane/Wool Keratin/Silk Sericin Freeze-Drying Composite Membrane for Heavy Metal Ions Adsorption

Wool keratin(WK)and silk sericin(SS)have the ability to interact with metal ions.In order to take advantage of this potential,a novel environmentally friendly waterborne polyurethane(WPU)/WK/SS membrane named as WPU&WK&SS membrane with crosslinked structure was constructed by freeze-drying via self-assembly style.Surface morphology and chemical structure characterization were investigated by scanning electron microscopy(SEM)and Fourier transform infrared spectroscopy(FT-IR).In addition,the adsorption experiments of Cu2+and Cr6+were performed to evaluate the adsorption of WPU&WK&SS membrane,including adsorption kinetics,adsorption isotherm models and various factors affecting adsorption.Further investigation indicates that the maximum adsorption capacity of Cu2+and Cr6+can reach 54.21 mg·g-1and 85.21 mg·g-1,respectively,which are higher than most of the reported adsorbents.Through adsorption kinetics and thermodynamic analysis,it is find that the pseudo-second-order kinetic equation and the Langmuir adsorption isotherm model are more suitable for the static adsorption of Cu2+and Cr6+by WPU&WK&SS membrane.

Cell Growth and Desorption on the Surface of Temperature-sensitive Semi-IPNs Hydrogels Based on Silk Sericin

Semi-interpenetrating （semi-IPNs） hydrogels containing biocompatible silk sericin （SS） and poly（N-isopropylacrylamide）（PNIPAM） were prepared as novel cellular matrices. Their maximum swelling degree and basic characteristics for biomedical applications such as mouse ？broblasts （L929） cell proliferation and desorption were investigated. The results showed that the incorporation of high hydrophilic SS into PNIPAM hydrogel increased the maximum swelling degree of the semi-IPNs hydrogels, and the adhesion and growth of the L929 on semi-IPNs hydrogels were at least comparable to, or even better than, that on conventional PNIPAM hydrogel. In addition, L929 cells were found to detach from the hydrogels surface naturally by controlling environmental temperature. These results suggest great potential of semi-IPNs hydrogels in tissue engineering.

Temperature-pH Sensitive IPN Hydrogels Composed of Silk Sericin and Poly(N-isopropylacrylamide)

Interpenetrating polymer network （IPN） composed of silk sericin （SS） and poly（N-isopropylacrylamide） （PNIPAAm） was prepared. The morphology of the IPNs, in which the SS phase was stained with ammonium cuprate, was examined with TEM and a relative homogeneous distribution of the two polymers was exhibited. The swelling behavior of the IPN hydrogels showed both temperature and pH dependences.

Selective Adsorption of Ag(I) from Electronic Waste Leachate Using Modified Silk Sericin

A novel biosorbent was synthesized by grafting bisthiourea(BTU)on a silk sericin(SS)matrix.This biosorbent was denoted as BTU-SS and characterized by Fourier transform infrared spectroscopy(FTIR),zeta potential measurements,elemental analysis,and X-ray photoelectron spectroscopy(XPS).As revealed by the adsorption experiments,both BTU-SS and SS showed low affinity towards coexisting base metallic ions in Ag(I)-Cu(II)-Zn(II)-Ni(II)-Pb(II)electronic waste leachate mixtures,while their adsorption capacities towards Ag(I)reached 30.5 and 10.4 mg∙g-1 at a pH of 5.0,respectively.BTU-SS showed higher selectivity towards Ag(I)than SS,as revealed by the Ag(I)partition coefficients between the biosorbents and the leachate(16634.6 and 403.3,respectively).As further demonstrated by column experiments,BTU-SS allowed the separation of Ag(I)from an electronic waste leachate.Thermodynamic studies showed that the adsorption of Ag(I)was exothermic and spontaneous,while adsorption kinetic experiments revealed that chemisorption dominated the adsorption process with activation energies of 47.67 and 53.27 kJ∙mol-1 for BTU-SS and SS,respectively.FTIR and XPS analyses of fresh and Ag(I)-loaded BTU-SS further revealed an adsorption mechanism mainly involving electrostatic and coordination interactions.

Injectable silk sericin scaffolds with programmable shape-memory property and neuro-differentiation-promoting activity for individualized brain repair of severe ischemic stroke

Severe ischemic stroke damages neuronal tissue,forming irregular-shaped stroke cavities devoid of supporting structure.Implanting biomaterials to provide structural and functional support is thought to favor ingrowth of regenerated neuronal networks.Injectable hydrogels capable of in situ gelation are often utilized for stroke repair,but challenged by incomplete gelation and imprecise control over end-macrostructure.Injectable shape-memory scaffolds might overcome these limitations,but are not explored for stroke repair.Here,we report an injectable,photoluminescent,carbon-nanotubes-doped sericin scaffold(CNTs-SS)with programmable shape-memory property.By adjusting CNTs’concentrations,CNTs-SS′recovery dynamics can be mathematically calculated at the scale of seconds,and its shapes can be pre-designed to precisely match any irregular-shaped cavities.Using a preclinical stroke model,we show that CNTs-SS with the customized shape is successfully injected into the cavity and recovers its pre-designed shape to well fit the cavity.Notably,CNTs-SS’near-infrared photoluminescence enables non-invasive,real-time tracking after in vivo implantation.Moreover,as a cell carrier,CNTs-SS not only deliver bone marrow mesenchymal stem cells(BMSCs)into brain tissues,but also functionally promote their neuronal differentiation.Together,we for the first time demonstrate the feasibility of applying injectable shape-memory scaffolds for stroke repair,paving the way for personalized stroke repair.

Effect of silk sericin on morphology and structure of calcium carbonate crystal

In this paper, silk sericin was employed to regulate the mineralization of calcium carbonate （CaC03）. CaCO3 composite particles were prepared by the precipita- tion reaction of sodium carbonate with calcium chloride solution in the presence of silk sericin. The as-prepared samples were collected at different reaction time to study the crystallization process of CaCO3 by scanning electron microscopy （SEM）, Fourier transform infrared spectroscopy （FTIR）, thermogravimetric analysis （TGA） and X-ray diffraction （XRD）. The results showed that silk sericin significantly affected the morphology and crystallographic polymorph of CaCO3. With increasing the reaction time, the crystal phase of CaCO3 transferred from calcite dominated to vaterite dominated mixtures, while the morphology of CaCO3 changed from disk-like calcite crystal to spherical vaterite crystal. These studies showed the potential of silk sericin used as a template molecule to control the growth of inorganic crystal.

Co-encapsulation efficiency of silk sericin-alginate-prebiotics and the effectiveness of silk sericin coating layer on the survival of probiotic Lactobacillus casei

The use of silk sericin protein as a biomaterial to co-encapsulate probiotic Lactobacillus casei TISTR 1463 with alginate and various prebiotics was determined.In addition,0.2%silk sericin was also evaluated as a coating material to improve the viability of probiotic cells.Silk sericin coating has the potential to enhance probiotic survival in freeze-dried microcapsules.Under refrigerated storage condition of 4℃for 120 days,alginate-silk sericin-maltitol with silk sericin coating(ASM-C)provided the best performance with the lowest inactivation rate(k)and the highestδparameter(the first decimal reduction time)applied by the log-linear and Weibull models,respectively.However,the stability was relatively low at the temperature of 30℃.Co-encapsulation of alginate-silk sericin-prebiotic and coated with silk sericin exerted a protective impact on the strain survival when exposed to high temperatures and transited through the digestive system.

Degumming of Silk Fibers by CO₂Supercritical Fluid

This paper is to study a new method to remove sericin from raw silk fiber. This new process is done using an organic acid as a pretreatment and then using CO2 supercritical fluid to remove sericin from silk fiber. This method would be a huge break from the traditional environmentally unsustainable methods used today. This new processing method keeps the removed sericin in a clean state that can be used as a highly marketable silk protein in the medical and cosmetic industries.

The Application of Ultrasonic in the Refining of Waste Silk Material

The treatment effect of ultrasonic on waste silk material was studied in this paper. The results show that Ultrasonic can emulsify the pupal fat and accelerate the dissolving of sericin. For high pupal fat containing material, high temperature, high pH value and long time which may result in damage to silk fibre are not required and different levels of sericin can be kept according to requirement in ultrasonic refining. In addition, silk fibres are swollen and the breaking elongation of silk fibre is increased on prolonged ultrasonic treatment. But the breaking tenacity is damaged slightly.

蚕丝蛋白对人皮肤成纤维细胞的保湿性能

运用细胞干燥损伤模型、细胞酶联免疫法等方法,向干燥损伤的HSF细胞添加各类蚕丝蛋白液和对含有各类蚕丝蛋白液的HSF细胞做干燥损伤处理,研究各类蚕丝蛋白对干燥损伤HSF细胞的修复与保护功效。基于细胞酶联反应,测定蚕丝蛋白对干燥损伤HSF细胞水通道蛋白3与透明质酸的表达。试验数据表明,全蚕丝蛋白对HSF细胞抗干燥损伤的功效显著,且相较丝素蛋白和丝胶蛋白的功效更明显,其中丝胶蛋白相较丝素蛋白的功效更明显。结果表明蚕丝蛋白对人皮肤成纤维细胞具有良好的屏障功能、保湿功效。

后道拉伸对聚丁二酸丁二醇酯/丝胶蛋白共混纤维结构与性能的影响

为提高纤维的力学性能,采用后道拉伸处理聚丁二酸丁二醇酯(poly(butylene succinate),PBS)/丝胶蛋白(silk sericin,SS)共混纤维,研究拉伸倍数和拉伸温度对纤维形态结构、化学结构、热性能、力学性能与降解性能的影响。结果表明,随着拉伸倍数增加,PBS与丝胶蛋白发生相对位移,纤维表面沿拉伸方向出现明显条纹;随着拉伸温度增加,纤维表面的条纹减少,表明温度的增加提高了PBS分子链的运动能力,使纤维保持致密结构。随着拉伸倍数和拉伸温度的提高,共混纤维的力学性能和结晶度呈现先增加后减小的趋势,在后道拉伸倍数为4倍,拉伸温度为75℃时,纤维的结晶度可达61.30%,此条件下的纤维断裂强度最大为2.0 cN/dtex,接近粘胶纤维的力学强度,可满足纺纱、非织造等纺织加工工艺的要求。

丝胶蛋白基多孔碳的制备及其吸波性能研究

为解决传统多孔碳材料制备工艺繁杂、污染大、成本高等问题,采用活化-碳化法处理废弃的丝胶蛋白,制备原位杂原子掺杂丝胶蛋白基多孔碳材料(Silk sericin-based derived porous carbon,SSC)。采用扫描电镜、X射线衍射仪和拉曼光谱仪对试样的形貌和结构进行表征,通过矢量网络分析仪测试材料电磁参数,探讨热处理温度对材料吸波性能的影响。结果表明:当丝胶蛋白和活化剂KHCO3质量比为2∶1、热处理温度为700℃时,制备的试样SSC-700具有最优吸波性能,且试样在16.55GHz处达到最小反射损耗(-51.30dB),匹配厚度为1.4mm,有效吸波频宽为3.60GHz(14.40~18.00GHz);SSC-700良好的吸波性能归因于材料自身的导电损耗和多种极化机制的协同作用。研究为生物质碳材料的开发和利用提供了新策略,制得的SSC材料在吸波领域具有广泛的应用前景。

蚕丝丝胶蛋白的结构、性能及利用

丝绸厂排放的废水中含有大量的丝胶蛋白。丝胶蛋白是一种球状蛋白 ,含有多种多肽 ,由 18种氨基酸组成 ,含有较多的丝氨酸、天门冬氨酸和甘氨酸 ,极性侧链氨基酸占 74.6 1%。丝胶蛋白具有易溶、吸水、凝胶化、可改性和抗氧化等特性 ,在化妆品、食品。

蚕丝丝胶蛋白的利用研究

丝胶是球状蛋白 ,可从下茧、废丝中经高温脱胶、浓缩、干燥制得 ,也可从丝绸制造厂家排放的废水中大量提取。丝胶二级结构主要以无规卷曲结构为主和部分 β构象 ,含有 74.61%的极性侧链氨基酸。丝胶具有良好的吸放湿性能、抗氧化性、营养及保健功能 ,可用作合成纤维的涂层材料、化妆品和食品的添加剂 ,还可在医药、固定化酶载体、高分子材料和水泥浆添加剂等方面被开发利用。回收利用丝胶 ,对保护环境和增加经济效益具有重要意义。

丝胶蛋白抗氧化肽的酶法制备及功能评价

为进一步开发利用废蚕丝,充分挖掘丝胶蛋白的可利用程度,该文研究了6种蛋白酶水解制备丝胶肽及产品的抗氧化活性。筛选出Alcalase碱性蛋白酶为制备丝胶抗氧化肽的理想蛋白酶,并以ABTS体系评价了丝胶肽的抗氧化活性。通过单因素试验研究了反应时间、底物浓度、反应温度、pH值、酶底物比对酶水解制备丝胶肽的影响;并通过回归正交旋转试验设计对水解条件进行优化,建立各因素与水解度和抗氧化活性的数学模型,确定Alcalase酶水解丝胶蛋白的最佳水解条件为:反应时间240min,底物浓度2%,反应温度55℃,pH8.5,酶底物比2.375%。最佳水解条件下水解度为33.35%,ABTS清除活性为43.19%。该研究为开发丝胶抗氧化肽功能产品提供了技术依据。

再生丝素/丝胶共混蛋白水溶液的静电纺丝

采用静电纺丝方法制备了再生丝素/丝胶共混纤维,分析了共混配比对再生丝素/丝胶水溶液流变性能和静电纺可纺性的影响,通过扫描电镜、拉曼光谱和DSC等手段研究了所得纤维的形态和微细结构及其力学性能。研究结果表明:随着溶液中丝胶含量的增加,体系的表观粘度增大,静电纺纤维的直径减小且直径分布变窄;并且丝胶的存在有利于丝素蛋白从无规卷曲或α-螺旋结构向β-折叠结构转变,由此可提高静电纺纤维的力学性能。

蚕丝丝胶蛋白的抗氧化作用

蚕丝经过高温高压水脱胶处理、高温高压碱性水脱胶处理和中性蛋白酶水解后,制成了6种不同分子量范围的丝胶肽及其水解物。利用家蚕5龄蚕血液进行了丝胶肽抑制黑色素生成试验,研究结果表明这6种丝胶肽都具有抑制黑色素生成的作用。高温高压水处理获得的丝胶肽抗氧化作用最强,高温高压弱碱性水处理获得的丝胶肽抗氧化作用略低,而中性蛋白酶水解的丝胶肽对黑色素形成的抑制率最低。当丝胶质量分数达到0.5%,前二类丝胶的抑制率可分别达到55%和50%,而第三类酶解丝胶对黑色素生成的抑制率为20%￣25%,仅为前二种的一半还不到。这些实验结果说明,高温或高温弱碱性处理的丝胶蛋白更适合于化妆品、护肤品、保健品等领域的应用。

丝胶蛋白及其酶解产物的保湿与抗氧化和抑制酪氨酸酶活性分析

从蚕茧中提取丝胶蛋白并酶解为丝胶蛋白肽，考察丝胶蛋白与不同分子质量丝胶蛋白肽的保湿性能以及对1，1-二苯基-2-三硝基苯肼（DPPH）自由基的清除能力和对酪氨酸酶活性的抑制作用，为高效、合理开发利用丝胶蛋白资源提供基础依据。结果表明：0～14h内，质量分数为5％、10％和15％的丝胶蛋白肽的保湿性能可与相同质量分数的甘油相媲美，保湿时间较长，分子质量较大的丝胶蛋白肽溶液的保湿性能也较优；丝胶蛋白及不同分子质量的丝胶蛋白肽均有一定的清除DPPH自由基和抑制酪氨酸酶活性的能力，尤以分子质量较小的丝胶蛋白肽的清除与抑制能力相对较强，同一种分子质量的丝胶蛋白肽，其清除DPPH自由基的能力和抑制酪氨酸酶活性的能力则呈现明显的量效关系。生产上可以根据丝胶蛋白的用途制备不同分子质量的丝胶蛋白酶解产物。

丝胶蛋白/羟基磷灰石复合支架材料的制备及性能研究

羟基磷灰石(HA)是骨组织中无机物的主要成分。利用丝胶蛋白(SS)良好的生物相容性、生物降解性、细胞相容性,以及含有的羧基和羟基能与Ca2+紧密结合的特点,将氢氧化钙和磷酸以湿法合成的羟基磷灰石按一定的比例加入到浓缩后的丝胶蛋白溶液中,经冷冻干燥制备成丝胶蛋白/羟基磷灰石复合支架材料,期望用于骨替代和骨缺损修复。对丝胶蛋白/羟基磷灰石复合支架材料进行扫描电镜(SEM)、X射线衍射(XRD)、红外吸收光谱(FTIR)、热力学性能以及力学性能等检测,并探讨不同原料配比对材料结构与性能的影响。结果表明,丝胶蛋白/羟基磷灰石复合支架材料的孔隙分散均匀,孔隙率33.0%～62.5%;支架材料中的HA呈弱结晶态,与人体骨组织中HA的晶体态相似,丝胶蛋白分子呈β折叠结构;随着复合支架材料中HA的比例不断增加,材料的热分解温度提高,热学性能改善,当HA的质量分数达到50%时,弹性模量增大到15.64MPa,呈现较好的结构性能。

苯乙烯在蚕丝丝胶上接枝共聚的研究

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。