Zeolitic imidazolate frameworks(ZIFs)are an important subclass of metal-organic frameworks(MOFs)with zeolite-type topology,which can be fabricated under ambient synthesis conditions.However,the applications of ZIFs ar...Zeolitic imidazolate frameworks(ZIFs)are an important subclass of metal-organic frameworks(MOFs)with zeolite-type topology,which can be fabricated under ambient synthesis conditions.However,the applications of ZIFs are commonly limited due to the weak hydrostability of their metal–ligand coordination bonds,particularly under humid and aqueous conditions.In this work,as an example,the hydrolysis behaviours of ZIF-L with a special focus on ZIF-L coatings were tested at aqueous conditions with a wide range of pHs to systematically study and fundamentally understand their structural stability and degradation mechanism.Pristine ZIF-L powder and ZIF-L coatings were severely damaged after only 24 h in aqueous media.Interestingly,the ZIF-L coatings showed two distinct hydrolyzation pathways regardless of pH conditions,exhibiting either a ring-shaped etching or unfolding behaviours.While the ZIF-L powders were hydrolyzed almost identically across all pH conditions.With this new understanding,a facile silk fibroin(SF)protein modification method was developed to enhance the hydrostability of ZIF-L coatings in aqueous media.The effect of protein concentration on surface coating was systemically studied.ZIF-L coating retained its surface morphology after soaking in water and demonstrated switchable super wetting properties and superior separation performance for oil/water mixture.As a result,the quick SF protein modification significantly enhanced the stability of ZIF-L coatings under various pHs,while retaining their switchable wetting property and excellent separation performance.展开更多
丝素蛋白是一种从蚕丝中提取的天然高分子纤维蛋白,有很好的抗氧化和减少光损伤的作用。为了研究丝素蛋白对皮肤光损伤的保护作用,以UVB诱导人角质形成细胞(HaCaT)损伤为模型,通过ELISA和荧光检测细胞内活性氧(ROS)和钙离子(Ca^(2+))的...丝素蛋白是一种从蚕丝中提取的天然高分子纤维蛋白,有很好的抗氧化和减少光损伤的作用。为了研究丝素蛋白对皮肤光损伤的保护作用,以UVB诱导人角质形成细胞(HaCaT)损伤为模型,通过ELISA和荧光检测细胞内活性氧(ROS)和钙离子(Ca^(2+))的水平,采用免疫荧光检测瞬时受体电位阳离子通道亚家族V成员1(TRPV1)和Claudin-1的表达。此外,还使用蛋白质印迹分析了紧密连接相关蛋白Occludin和Claudin-1的表达。结果表明,120 m J/cm^(2)的UVB刺激显著降低细胞活力,而100μg/m L丝素蛋白的存在显著增加细胞活力。UVB刺激导致细胞内活性氧水平升高,激活TRPV1通道,诱导细胞内Ca^(2+)水平增加。同时炎症因子白细胞介素1α(IL-1α)(P<0.01)和S100钙结合蛋白A8(S100A8)(P<0.05)水平也显著升高,引发炎症反应。添加丝素蛋白的HaCaT细胞受到UVB的影响则显著降低(P<0.05)。实验证明,UVB会破坏屏障蛋白,导致屏障蛋白Claudin-1和Occludin的表达下降。丝素蛋白的加入可以降低这种影响,保护细胞间紧密连接。因此,丝素蛋白可能具有降低氧化应激、屏障损伤和炎症发生,保护皮肤免受UVB诱导的光损伤的潜在能力。展开更多
Vibrational spectroscopy(ATR-FTIR and Raman) was used to investigate the interaction and conformation transition in the blend films of silk fibroin(SF) and silk-protein like polymers(P1, P2) containing the oligopeptid...Vibrational spectroscopy(ATR-FTIR and Raman) was used to investigate the interaction and conformation transition in the blend films of silk fibroin(SF) and silk-protein like polymers(P1, P2) containing the oligopeptide segments[(Ala) 4, GlyAlaGlyAla] which derived from the crystal region of spider dragline silk and silkworm(Bombyx mori) silk. The results revealed that the intermolecular hydrogen-bond interaction, which was formed between the molecular chains of SF and the oligopeptide segments in P1 and P2, induced a partial random coil/α-helix conformation transfer to β-sheet conformation after blending. And β-sheet and random coil/α-helix conformation coexisted in the SF/P1 and SF/P2 blend films, while the predominant conformations in the pure SF and P1 films were random coil/α-helix. These conclusions would be significant for artificial spinning of the regenerated silk fibroin.展开更多
基金supported by start-up funding from the School of Engineering,at the University of Edinburgh.
文摘Zeolitic imidazolate frameworks(ZIFs)are an important subclass of metal-organic frameworks(MOFs)with zeolite-type topology,which can be fabricated under ambient synthesis conditions.However,the applications of ZIFs are commonly limited due to the weak hydrostability of their metal–ligand coordination bonds,particularly under humid and aqueous conditions.In this work,as an example,the hydrolysis behaviours of ZIF-L with a special focus on ZIF-L coatings were tested at aqueous conditions with a wide range of pHs to systematically study and fundamentally understand their structural stability and degradation mechanism.Pristine ZIF-L powder and ZIF-L coatings were severely damaged after only 24 h in aqueous media.Interestingly,the ZIF-L coatings showed two distinct hydrolyzation pathways regardless of pH conditions,exhibiting either a ring-shaped etching or unfolding behaviours.While the ZIF-L powders were hydrolyzed almost identically across all pH conditions.With this new understanding,a facile silk fibroin(SF)protein modification method was developed to enhance the hydrostability of ZIF-L coatings in aqueous media.The effect of protein concentration on surface coating was systemically studied.ZIF-L coating retained its surface morphology after soaking in water and demonstrated switchable super wetting properties and superior separation performance for oil/water mixture.As a result,the quick SF protein modification significantly enhanced the stability of ZIF-L coatings under various pHs,while retaining their switchable wetting property and excellent separation performance.
文摘丝素蛋白是一种从蚕丝中提取的天然高分子纤维蛋白,有很好的抗氧化和减少光损伤的作用。为了研究丝素蛋白对皮肤光损伤的保护作用,以UVB诱导人角质形成细胞(HaCaT)损伤为模型,通过ELISA和荧光检测细胞内活性氧(ROS)和钙离子(Ca^(2+))的水平,采用免疫荧光检测瞬时受体电位阳离子通道亚家族V成员1(TRPV1)和Claudin-1的表达。此外,还使用蛋白质印迹分析了紧密连接相关蛋白Occludin和Claudin-1的表达。结果表明,120 m J/cm^(2)的UVB刺激显著降低细胞活力,而100μg/m L丝素蛋白的存在显著增加细胞活力。UVB刺激导致细胞内活性氧水平升高,激活TRPV1通道,诱导细胞内Ca^(2+)水平增加。同时炎症因子白细胞介素1α(IL-1α)(P<0.01)和S100钙结合蛋白A8(S100A8)(P<0.05)水平也显著升高,引发炎症反应。添加丝素蛋白的HaCaT细胞受到UVB的影响则显著降低(P<0.05)。实验证明,UVB会破坏屏障蛋白,导致屏障蛋白Claudin-1和Occludin的表达下降。丝素蛋白的加入可以降低这种影响,保护细胞间紧密连接。因此,丝素蛋白可能具有降低氧化应激、屏障损伤和炎症发生,保护皮肤免受UVB诱导的光损伤的潜在能力。
文摘Vibrational spectroscopy(ATR-FTIR and Raman) was used to investigate the interaction and conformation transition in the blend films of silk fibroin(SF) and silk-protein like polymers(P1, P2) containing the oligopeptide segments[(Ala) 4, GlyAlaGlyAla] which derived from the crystal region of spider dragline silk and silkworm(Bombyx mori) silk. The results revealed that the intermolecular hydrogen-bond interaction, which was formed between the molecular chains of SF and the oligopeptide segments in P1 and P2, induced a partial random coil/α-helix conformation transfer to β-sheet conformation after blending. And β-sheet and random coil/α-helix conformation coexisted in the SF/P1 and SF/P2 blend films, while the predominant conformations in the pure SF and P1 films were random coil/α-helix. These conclusions would be significant for artificial spinning of the regenerated silk fibroin.
