Binary hairy nanoparticles: Recent progress in theory and simulations

Binary polymer brushes, including mixed homopolymer brushes and diblock copolymer brushes, are an attractive class of environmentally responsive nanostructured materials. Owing to microphase separation of the two chemically distinct components in the brush, multifaceted nanomaterials with functionalized and patterned surfaces can be obtained. This review summarizes recent progress on the theory and simulations related to binary polymer brushes grafted to flat, spherical, and cylindrical substrates, with a focus on patterned morphologies of multifaceted hairy nanoparticles, an intriguing class of hybrid nanostructured particles (e.g., nanospheres and nanorods). In particular, powerful field theory and particle-based simulations suitable for revealing novel structures on these patterned surfaces, including self-consistent field theory and dissipative particle dynamics simulations, are emphasized. The unsolved yet critical issues in this research field, such as dynamic response of binary polymer brushes to environmental stimuli and the hierarchical self-assembly of binary hairy nanoparticles, are briefly discussed. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 1583–1599     

固载脯氨酸的毛发状纳米粒子的合成及其应用研究

毛发状粒子表面的聚合物链是一个具有一定流动性的动态体系,其负载的催化剂综合了均相和非均相负载催化剂的优点,为手性催化剂的负载和实用化提供了一条新的途径。本文利用Si O2纳米粒子表面修饰制得的功能基,通过表面RAFT聚合,并经过氨基去保护后制得负载脯氨酸的毛发状纳米粒子。通过热重、红外和透射电镜对毛发状二氧化硅纳米粒子的结构进行表征,并将获得的毛发状纳米粒子作为催化剂直接催化不对称Aldol反应。     

Successive stepwise evolution of host layer‐stacking framework upon the intercalation of mobile vapor guests within side‐chain layers

For the ordered phases of hairy‐rod semiconductive poly(2,5‐bis(3‐tetradecylthiophene‐2‐yl)thieno[3,2‐b]thiophene) (PBTTT) sandwiched in between crystalline platelets of hexamethylbenzene, the successive stepwise evolution of layer‐stacking framework upon guest intercalation has been studied in this research. The direct consequence of the guest intercalation into side‐chain layers is evaluated to cause the lateral shift of thiophene backbones along π–π stacking, resulting in stepwise shift of ultraviolet absorption wavelength. The thermal motions of vapor guests within disordering side‐chain layers subsequently cause progressive expansion of host stacking framework. With the increase in side‐chain length, thicker layers of disordering side chains in liquid crystals (LCs) accommodate additional vapor guests and larger amplitudes of thermal motions of guests, hence promoting the level of reversible d‐spacing change. The mixing between mobile vapor guests and aliphatic side chains is clarified as the mechanism of guest intercalation, which rationalizes successive guest intercalation during heating and the contribution of disordering side‐chain layers. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 1448–1456     

Datura stramonium hairy roots tropane alkaloid content as a response to changes in Gamborg’s B5 medium

Hairy roots are less susceptible to manipulation by changes in medium composition than callus and cell suspension cultures. However, when the individual components of the Gamborg’s B₅ medium were modified one by one, several of them modified the yield of root cultures. Nitrogen (N) source changes, the absence of phosphorus (P), calcium (Ca), and cobalt (Co), and the increase in the sucrose content of the medium increased the level of alkaloids inDatura stramonium hairy root cultures. The use of ammoniun as N source provoked the alkaloid excretion into the medium. The addition of different auxins inhibited the alkaloid accumulation, but the addition of abscisic acid (ABA) did not change the alkaloid content of the cultures. The use of MeJa increased the content of hyoscyamine to 100%.     

Friction coefficients of spheres having sticky or hairy surfaces

The theoretical equations for friction coefficients of spheres having sticky or hairy surfaces are presented. In the present treatment, the sticky surface is represented by a higher viscosity of fluid in the surface layer and the hairy surface is assumed to have a porous structure. The friction coefficients are given as functions of the thickness of the surface layer, the fluid viscosity in the surface layer and the segmental density of hairy chains.     

Determination of lignans,phenolic acids and antioxidant capacity in transformed hairy root culture of Linum usitatissimum

Hairy root culture is a promising alternative method for the production of secondary metabolites. In this study, transformed root of Linum usitatissimum was established using Agrobacterium rhizogenes A4 strain from root cultures for lignans, phenolic acids and antioxidant capacity determination. Total lignin content (secoisolariciresinol diglucoside, secoisolariciresinol and matairesinol) was 55.5% higher in transformed root cultures than in the non-transformed root culture. Secoisolariciresinol was detected in higher concentration (2.107 μmol/g DM) in the transformed root culture than non-transformed culture (1.099 μmol/g DM). Secoisolariciresinol diglucoside and matairesinol were exclusively detected in the transformed root culture, but were not found in the non-transformed root culture. The overall production of phenolic acids in transformed roots was approximately 3.5 times higher than that of the corresponding non-transformed culture. Free radical scavenging DPPH˙ and ABTS˙⁺ assays showed 2.9-fold and 1.76-fold higher anti-oxidant activity in transformed root culture as compared to non-transformed.     

Overexpression in Catharanthus roseus hairy roots of a truncated hamster 3-hydroxy-3-methylglutaryl-CoA reductase gene

Catharanthus roseus (L.) G. Don hairy roots harboring hamster 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) (EC 1.1.1.88) cDNA without membrane-binding domain were evaluated by quantifying the levels of sterols and some indol-alkaloids. Clone 236, with the highest hybridization signal, had the lowest soluble and microsomal HMGR activity and produced more ajmalicine and catharanthine than the control but had reduced campesterol concentration. Clone 19, with low hybridization signal, had high soluble HMGR activity and produced high levels of campesterol and five to seven times more serpentine than the control but a low level of ajmalicine and no accumulation of catharanthine. These results suggest a possible role for HMGR in indole alkaloid biosynthesis and a possible cosuppression of both the endogenous and foreign HMGR genes in clone 236.     

Studies on mass production of transformed Panax ginseng hairy roots in bioreactor

The growth properties of Panax ginseng hairy roots transformed by Agrobacterium rhizogenes were compared between flask and aerated column or stirred bioreactor. In flask cultures, sucrose, initially 30 g/L, was nearly exhausted after 45 d of culture. The pH of the medium dropped from 5.5 to 4.96 after 10 d, but afterward it gradually increased to 6.4. After 45 d, hairy roots grew about 16-folds. The growth rate of hairy roots in air-bubble column or stirred bioreactor cultures was 1.13 (1.11) to 1.23 (1.20) g fresh wt (dry wt)/(g of cells·d), respectively. For both bioreactors, growth was about three times as high as in the flask cultivation.     

铕对决明发根生长及有效成分生成的作用

以决明发根为材料,在培养基中附加０．００１～１０ｍｇ．Ｌ＾－１Ｅｕ＾３＋（ＥｕＣ１３）,测量发根的鲜重和干重,用高效液相色谱法测定游离蒽醌化合物含量。发有低剂量（０．００１,０．０１,１．０ｍｇ．Ｌ＾－１）Ｅｕ＾３＋抑制生长,０．００１ｍｇ．Ｌ＾－１Ｅｕ＾３＋抑制作用最强,干重比对照降低２２％;较低剂量（１０ｍｇ．Ｌ＾－１）Ｅｕ＾３＋处理的含量高于对照２６＾,高于Ｅｕ＾３＋１．０ｍｇ．Ｌ＾－１处理     

Molecular and Crystal Structure of 7—Hydroxy—6,8—dimethoxyl—coumarin

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