Hydrophilic silica/copolymer nanoparticles of SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) are prepared by silica surface-initiating atom transfer radical polymerization (SI-ATRP) of poly (ethylene glycol) methyl e...Hydrophilic silica/copolymer nanoparticles of SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) are prepared by silica surface-initiating atom transfer radical polymerization (SI-ATRP) of poly (ethylene glycol) methyl ether methacrylate (PEGMA) and poly(ethylene glycol) methacrylate (PEG), by using Three molar ratios of SiO<sub>2</sub>-Br/PEGMA/PEG as 1/42.46/19.44, 1/42.46/38.88 and 1/42.46/77.76. Their temperature sensitive behaviour, pH response and surface properties as protein-resistance coatings are characterized. 220 nm core-shell nanoparticles as P(PEGMA)-b-P(PEG) shell grafted on SiO2 core are formed in water solution, which gained LCST at 60<sup>。</sup>C - 77<sup>。</sup>C and good dispersion in water when pH > 5.0. The water-casted films by SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) obtain a little rough surface (Ra = 26.8 - 29.7 nm). While, the introduction of P(PEG) segments could slight increase the protein-repelling adsorption of SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) films (△f = ?6.96 Hz ~ ?7.25 Hz) compared with SiO2-g-P(PEGMA) films (△f = ?9.5 Hz). Therefore, SiO2-g-P(PEGMA)-b-P(PEG) could be used as protein-resistance coatings.展开更多
In the beginning everything was explained in Biochemistry in terms of hydrogen-bonds (HB). Then, the devastating blow, known as the HB-inventory argument came;hydrogen bonding with water molecules compete with intramo...In the beginning everything was explained in Biochemistry in terms of hydrogen-bonds (HB). Then, the devastating blow, known as the HB-inventory argument came;hydrogen bonding with water molecules compete with intramolecular hydrogen-bonds. As a result, the HBs paradigm fell from grace. The void created was immediately filled by Kauzmann’s idea of hydrophobic (HφO) effect which reigned supreme in biochemical literature for over 50 years (1960-2010). Cracks in the HB-inventory argument on one hand, and doubts about the adequacy of Kauzmann’s model for the HφO effect, have led to a comeback of the HBs, along with a host of new hydrophilic (HφI) effects. The HφO effects lost much of its power - which it never really had - in explaining protein folding and protein-protein association. Instead, the more powerful and richer repertoire of HφI effects took over the reins. The interactions also offered simple and straightforward answers to the problems of protein folding, and protein-protein association.展开更多
A new approach to the problem of cold denaturation is presented. It is based on solvent-induced effects operating on hydrophilic groups along the protein. These effects are stronger than the corresponding hydrophobic ...A new approach to the problem of cold denaturation is presented. It is based on solvent-induced effects operating on hydrophilic groups along the protein. These effects are stronger than the corresponding hydrophobic effects, and they operate on the hydrophilic groups which are plentiful than hydrophobic groups. It is shown that both heat and cold denaturation can be explained by these hydrophilic effects.展开更多
通过使用美国国立生物技术信息中心(National Center for Biotechnology Information,NCBI)数据库检索出斑马鱼Smyd1a蛋白的氨基酸序列信息,对其进行生理生化分析,并通过NBCI寻找同源性高的不同种属的序列构建系统发育树。结果显示:Smy...通过使用美国国立生物技术信息中心(National Center for Biotechnology Information,NCBI)数据库检索出斑马鱼Smyd1a蛋白的氨基酸序列信息,对其进行生理生化分析,并通过NBCI寻找同源性高的不同种属的序列构建系统发育树。结果显示:Smyd1a蛋白的氨基酸数量是489个,分子量是56376.54 Da,理论等电点是6.27;该蛋白中,谷氨酸(Glu)含量最高,为8.4%;其次是亮氨酸(Leu)和丙氨酸(Ala),分别为8.0%和7.0%。Smyd1a是一个亲水蛋白质,但不是一个分泌蛋白,不存在跨膜螺旋区域,存在蛋白质的无规则卷曲等构象,Smyd1a属于SET家族。展开更多
Poly（vinylidenefluoride-hexafluoropropylene） （PVDF-HFP） nanofiber membranes with improved hydrophilicity and protein fouling resistance via surface graft copolymerization of hydrophilic monomers were prepared. The...Poly（vinylidenefluoride-hexafluoropropylene） （PVDF-HFP） nanofiber membranes with improved hydrophilicity and protein fouling resistance via surface graft copolymerization of hydrophilic monomers were prepared. The surface modification involves atmospheric pressure glow discharge plasma （APGDP） pretreatment followed by graft copolymerization of poly（ethylene glycol） methyl ether methacrylate （PEGMA）. The success of the graft modification with PEGMA on the PVDF-HFP fibrous membrane is ascertained by X-ray photoelectron spectroscopy （XPS） and attenuated total reflectance Fourier transform infrared measurements （ATR-FTIR）. The hydrophilic property of the nanofiber membranes is assessed by water contact angle measurements. The results show that the PEGMA grafted PVDF-HFP nanofiber membrane has a water contact angle of 0° compared with the pristine value of 132°. The protein adsorption was effectively reduced after PEGMA grafting on the PVDF-HFP nanofiber membrane surface. The PEGMA polymer grafting density on the PVDF-HFP membrane surface is measured by the gravimetric method, and the filtration performance is characterized by the measurement of water flux. The results indicate that the water flux of the grafted PVDF-HFP fibrous membrane increases significantly with the increase of the PEGMA grafting density.展开更多
文摘Hydrophilic silica/copolymer nanoparticles of SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) are prepared by silica surface-initiating atom transfer radical polymerization (SI-ATRP) of poly (ethylene glycol) methyl ether methacrylate (PEGMA) and poly(ethylene glycol) methacrylate (PEG), by using Three molar ratios of SiO<sub>2</sub>-Br/PEGMA/PEG as 1/42.46/19.44, 1/42.46/38.88 and 1/42.46/77.76. Their temperature sensitive behaviour, pH response and surface properties as protein-resistance coatings are characterized. 220 nm core-shell nanoparticles as P(PEGMA)-b-P(PEG) shell grafted on SiO2 core are formed in water solution, which gained LCST at 60<sup>。</sup>C - 77<sup>。</sup>C and good dispersion in water when pH > 5.0. The water-casted films by SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) obtain a little rough surface (Ra = 26.8 - 29.7 nm). While, the introduction of P(PEG) segments could slight increase the protein-repelling adsorption of SiO<sub>2</sub>-g-P(PEGMA)-b-P(PEG) films (△f = ?6.96 Hz ~ ?7.25 Hz) compared with SiO2-g-P(PEGMA) films (△f = ?9.5 Hz). Therefore, SiO2-g-P(PEGMA)-b-P(PEG) could be used as protein-resistance coatings.
文摘In the beginning everything was explained in Biochemistry in terms of hydrogen-bonds (HB). Then, the devastating blow, known as the HB-inventory argument came;hydrogen bonding with water molecules compete with intramolecular hydrogen-bonds. As a result, the HBs paradigm fell from grace. The void created was immediately filled by Kauzmann’s idea of hydrophobic (HφO) effect which reigned supreme in biochemical literature for over 50 years (1960-2010). Cracks in the HB-inventory argument on one hand, and doubts about the adequacy of Kauzmann’s model for the HφO effect, have led to a comeback of the HBs, along with a host of new hydrophilic (HφI) effects. The HφO effects lost much of its power - which it never really had - in explaining protein folding and protein-protein association. Instead, the more powerful and richer repertoire of HφI effects took over the reins. The interactions also offered simple and straightforward answers to the problems of protein folding, and protein-protein association.
文摘A new approach to the problem of cold denaturation is presented. It is based on solvent-induced effects operating on hydrophilic groups along the protein. These effects are stronger than the corresponding hydrophobic effects, and they operate on the hydrophilic groups which are plentiful than hydrophobic groups. It is shown that both heat and cold denaturation can be explained by these hydrophilic effects.
文摘通过使用美国国立生物技术信息中心(National Center for Biotechnology Information,NCBI)数据库检索出斑马鱼Smyd1a蛋白的氨基酸序列信息,对其进行生理生化分析,并通过NBCI寻找同源性高的不同种属的序列构建系统发育树。结果显示:Smyd1a蛋白的氨基酸数量是489个,分子量是56376.54 Da,理论等电点是6.27;该蛋白中,谷氨酸(Glu)含量最高,为8.4%;其次是亮氨酸(Leu)和丙氨酸(Ala),分别为8.0%和7.0%。Smyd1a是一个亲水蛋白质,但不是一个分泌蛋白,不存在跨膜螺旋区域,存在蛋白质的无规则卷曲等构象,Smyd1a属于SET家族。
基金supported by the National Natural Science Foundation of China(No.50673019).
文摘Poly（vinylidenefluoride-hexafluoropropylene） （PVDF-HFP） nanofiber membranes with improved hydrophilicity and protein fouling resistance via surface graft copolymerization of hydrophilic monomers were prepared. The surface modification involves atmospheric pressure glow discharge plasma （APGDP） pretreatment followed by graft copolymerization of poly（ethylene glycol） methyl ether methacrylate （PEGMA）. The success of the graft modification with PEGMA on the PVDF-HFP fibrous membrane is ascertained by X-ray photoelectron spectroscopy （XPS） and attenuated total reflectance Fourier transform infrared measurements （ATR-FTIR）. The hydrophilic property of the nanofiber membranes is assessed by water contact angle measurements. The results show that the PEGMA grafted PVDF-HFP nanofiber membrane has a water contact angle of 0° compared with the pristine value of 132°. The protein adsorption was effectively reduced after PEGMA grafting on the PVDF-HFP nanofiber membrane surface. The PEGMA polymer grafting density on the PVDF-HFP membrane surface is measured by the gravimetric method, and the filtration performance is characterized by the measurement of water flux. The results indicate that the water flux of the grafted PVDF-HFP fibrous membrane increases significantly with the increase of the PEGMA grafting density.
