纳米球形聚电解质刷与蛋白质的相互作用研究
详细信息    本馆镜像全文|  推荐本文 |  |   获取CNKI官网全文
摘要
聚电解质与生物大分子的相互作用研究能为其在蛋白质分离纯化、药物控释、创口修复、生物传感等领域的应用提供理论基础,因而成为当今最热门的科研方向之一。聚合物修饰的纳米粒子可以选择性地吸附蛋白质、酶、核酸、多糖和脂类等,也能注入人体血液中,并到达人脑和细胞。纳米球形聚电解质刷兼具聚电解质和纳米粒子的特性,既能选择性吸附蛋白质,也能通过改变环境条件可控地释放,因而能作为蛋白质固载、纯化、分离的载体,应用于靶向给药、疾病诊断和纳米生物反应器等领域。
     本文采用光乳液聚合方法,在粒径约为100nm的聚苯乙烯核表面上制备了厚度在30至150nm之间的阴离子型(聚丙烯酸)刷、阳离子型(聚2-氨基乙基酯盐酸盐)刷及核内包覆有四氧化三铁纳米粒子的磁性聚丙烯酸刷,研究了聚电解质刷可控吸附及脱附蛋白质的机理和影响因素,比较了阴离子刷与阳离子刷吸附蛋白质的行为差异,并将固载酶的球形聚丙烯酸刷和磁性聚丙烯酸刷作为纳米反应器进行酶促反应,观察了被聚合物刷固载前后酶的催化活性变化。主要的研究内容及结论如下:
     1.以牛血清蛋白(BSA)作为模型蛋白质,研究了其与聚丙烯酸刷(PAA-SPB)的相互作用。结合浊度滴定、动态光散射(DLS)和zeta电位的研究方法,从相态、尺寸和电荷的角度定性地观察了BSA与PAA-SPB相互作用随pH的变化。随着体系pH的降低,蛋白质与刷子呈现出吸附、团聚和脱附三种状态。等温滴定量热法(ITC)则从热力学和动力学角度提供了相互作用的定量信息,包括吸附过程中的热力学参数、结合强度及吸附量。小角X光光散射(SAXS)则观察到刷子吸附蛋白质前后结构上的细微差异,证实了蛋白质吸附于刷子层中。研究表明,蛋白质与聚电解质刷的相互作用主要是静电相互作用。体系的pH和离子强度共同决定了相互作用的强弱及蛋白质吸附量的大小。
     2.研究了阳离子型聚(2-氨基乙基酯盐酸盐)刷(PAEMH-SPB)与蛋白质BSA的相互作用。采用与1.中相同的研究手段,发现随着pH值的增加,阳离子刷与BSA也包含吸附、团聚和脱附三个阶段。但是,阳离子刷与BSA相互作用的pH窗口比阴离子刷更宽。除了pH和离子强度外,蛋白质与刷子的化学计量比和刷子的链长也能影响相互作用的pH窗口大小及吸附量。因此,通过调节体系的pH、离子强度、化学计量比和刷子的链长,阳离子刷能可控地吸附和脱附BSA。
     3.通过比较不同蛋白质与阴/阳离子刷的相互作用,发现阴离子刷与BSA/BLG(β-乳球蛋白)的相互作用行为较为相似,而阳离子刷吸附及脱附BSA/BLG的pH窗口却差别很大。因此,阴离子刷无法将BSA和BLG这两种等电点相近的蛋白质分开,而阳离子刷则能实现BSA和BLG的分离。这是由蛋白质表面电势的差异所致。通过DelPhi软件模拟,发现BLG的负电荷簇尺寸较大且分布很集中,而且具有类似偶极性的正负电荷簇。而BSA的“负电荷补丁”则由几个离散的负电荷簇组成。本文还研究了碱性木瓜蛋白酶与阳离子刷的相互作用。证实与酸性蛋白质相比,碱性蛋白质与阳离子刷的相互作用pH区间更窄并向高pH值迁移,结合较弱,吸附量较小。通过调节体系的pH、离子强度、化学计量比和刷子的链长,阳离子刷能有效地分离BSA、BLG(?)木瓜蛋白酶,而阴离子刷能吸附并固载多种酸性蛋白质。
     4.采用纳米球形聚丙烯酸刷和磁性聚丙烯酸刷吸附和固载葡萄糖糖化酶,并用于催化淀粉水解反应,利用浊度滴定、等温滴定量热法(ITC)和吸附实验分别从定性和定量的角度研究了纳米球形聚丙烯酸刷和磁性聚丙烯酸刷与葡萄糖糖化酶的相互作用随pH和离子强度的变化。将固载葡萄糖糖化酶的聚丙烯酸刷进行酶促淀粉水解反应,发现固定于聚丙烯酸刷和磁性刷中的葡萄糖糖化酶活性并没有降低,反而还略有增加,这可能是因为聚丙烯酸刷与葡萄糖糖化酶间的静电相互作用和氢键缔合使酶能稳定地固定在聚电解质刷的内部,并随聚电解质刷均匀地分散在水溶液中,而刷子内部稳定的pH值和盐浓度环境为酶活性的发挥提供了良好的空间。
In recent years, interaction between polyelectrolyte (PE) and biomacromolecules has attracted many interests in biotechnology, which lead to multiple applications in protein separation, drug delivery, wound healing, and biosensing. PE modified nanoparticles (NPs) can be ideal candidate for selective adsorption of protein, enzyme, nucleic acid, polysaccharide, and lipid. Since NPs are small enough to interact with cellular machinery and potentially to reach previously inaccessible targets, such as the brain and blood. Spherical polyelectrolyte brushes (SPBs) as colloidal NPs can be used as carriers for protein immobilization and separation. Through adjusting surrounding conditions, SPBs can adsorb and desorb proteins tunably. Therefore, SPB should be ideal candidate for protein immobilization, purification, separation, and applied to targeting drug delivery, high-performance diagnostic assays, and nano-bioreactor.
     SPBs were synthesized by photo-emulsion polymerization, consisting of a polystyrene core with a diameter around100nm and a polyelectrolyte shell with a thickness from30to150nm densely grafted on the core surface. The polyelectrolyte shell consists of either weak anionic poly(acrylic acid)(PAA) or weak cationic poly(2-aminoethyl methacrylate hydrochloride)(PAEMH). Magnetic SPBs consist of magnetic nanoparticles in the polystyrene core and PAA chains. In this paper, the interactions between proteins and anionic SPBs as a function of pH and ionic strength have been systematically compared with that for cationic SPB in both qualitative and quantitative ways. Such studies provide valuable insight into the interaction mechanism between proteins and SPBs and effects on interaction. SPB and magnetic SPB were used as carrier for enzyme immobilization and as nano-sized bioreactor for catalytic reaction, and test enzymatic activity before and after the immobilization in SPB. Main work and conclusions as follow:
     1. Bovine serum albumin (BSA) is employed as model protein to investigate their interaction with PAA-SPBs. The pH dependence of phase state, architecture, interaction behavior between proteins and PAA-SPBs were examined by turbidimetric titration, dynamic light scattering (DLS), and zeta potential measurement. Results reveal the existence of three pH regions, corresponding to adsorption, aggregation, and desorption of BSA from SPB upon decreasing pH. Isothermal titration calorimetry (ITC) was applied to determine the amount of adsorption, binding affinity, and thermodynamics of BSA adsorption onto SPBs in quantitative way. Small angle X-ray scattering was employed to investigate the subtle change of shell structure of PAA-SPBs before and after adsorption of BSA, which demonstrated that BSA molecules were distributed inside the shell of SPBs. The interaction between proteins and SPBs is caused mainly by electrostatic interaction. Both pH and ionic strength of system influence the adsorption amount of BSA in PAA-SPBs simultaneously.
     2. Cationic spherical polyelectrolyte brushes were employed as carrier for BSA immobilization. In this section, we continue to investigate the interaction in both qualitative and quantitative ways, following the characterization methods as above. We also found that adsorption, aggregation, and desorption of BSA by cationic SPBs could be tuned by increasing pH. However, the extent of pH range for BSA and cationic SPBs was wider than anionic SPBs. In addition to pH and ionic strength, protein and SPBs stoichiometry, and SPB thickness can influence pH region for adsorption and adsorbed amount as well. Therefore, through modulating pH, ionic strength, bulk stoichiometry of system, and SPB thickness, cationic SPBs can adsorb and desorb BSA effectively under optimized conditions.
     3. Turbidimetric titration, DLS, zeta potential measurement, ITC, and adsorption measurement were used to investigate the interaction between various proteins and anionic/cationic SPBs. Results reveal that interaction behavior between anionic SPBs and BSA is very similar to BLG, while pH window for BSA adsorption by cationic SPBs is significantly different from that of BLG. Therefore, we find that it is difficult to use PAA-SPBs to discriminate these two proteins with similar pls. However, selective adsorption between BSA and BLG can be achieved with cationic SPBs by proper selection of pH, ionic strength, bulk stoichiometry, and SPB thickness. This may arise from the different electrostatic interaction behaviors between SPB and protein "charge patches" or "charge regulation". The larger negative charge patch of BLG distributes centrally. Furthermore, positive and negative charge patches of BLG display dipolar distribution. While, smaller negative charge patches of BSA distribute discretely. We also study the interaction between basic papain and cationic SPBs. Compared to acidic proteins, basic protein adsorption by cationic SPB is in a narrow pH region and shifts to higher pH value. Cationic SPBs adsorb basic protein much weaker than acidic proteins. The sequence of binding affinity and stoichiometry of proteins onto cationic SPBs was observed by ITC as BLG>BSA>papain, which resulted from the size, isoelectric point, and charge anisotropy of proteins. Therefore, through adjusting pH, ionic strength, bulk stoichiometry, and SPB thickness, cationic SPBs have potential applications in separation and selective binding of BSA, BLG, and papain under optimized conditions. While, anionic SPBs provide mild conditions for BSA and BLG co-immobilization.
     4. Spherical poly(acrylic acid) brushes (PAA-SPBs) and magnetic PAA-SPBs were employed as carriers for glucoamylase (GA) to catalyze amylolysis. Firstly, turbidimetric titration, ITC, and adsorption experiment were used to investigate the pH and ionic strength dependent interaction between GA and PAA-SPBs/magnetic PAA-SPBs in both qualitative and quantitative ways. Then, GA immobilization in PAA-SPBs and magnetic PAA-SPBs carried out under optimal conditions. We study the dynamics of amyloysis and activity of GA before and after immobilized in PAA-SPBs and magnetic PAA-SPBs. Experimental results demonstrate that immobilization of GA in PAA-SPBs and magnetic PAA-SPBs does not lead to the loss of activity of GA. The electrostatic attraction and hydrogen bonding between GA and PAA chains grafted on SPBs enhances the enzymatic activity, and SPBs provide stable surrounding such as pH and ionic strength for GA immobilization, so the GA immobilized in PAA-SPBs and magnetic PAA-SPBs displays higher catalytic activity than free GA.
引文
[1]Turgeon S L, Schmitt C, Sanchez C. Protein-polysaccharide complexes and coacervates[J]. Current Opinion in Colloid & Interface Science,2007,12 (4-5):166-178.
    [2]Becker A L, Henzler K, Welsch N, et al. Proteins and polyelectrolytes:A charged relationship[J]. Current Opinion in Colloid & Interface Science,2012,17 (2):90-96.
    [3]Cooper C L, Dubin P L, Kayitmazer A B, et al. Polyelectrolyte-protein complexes[J] Current Opinion in Colloid & Interface Science,2005,10 (1-2):52-78.
    [4]Kopaciewicz W, Rounds M A, Fausnaugh J, et al. Retention model for high-performance ion-exchange chromatography[J]. Journal of Chromatography A,1983,266 (26):3-21.
    [5]Lesin V, Ruckenstein E. Chromatographic probing of protein-sorbent interactions [J]. Journal of Colloid and Interface Science,1989,132 (2):566-577.
    [6]Rosenberg R D. Heparin, antithrombin, and abnormal clotting [J]. Annual Review Medicine,1978,29:367-378.
    [7]Imberty A, Lortat-Jacob H, Perez S. Structural view of glycosaminoglycan-protein interactions[J]. Carbohydrate Research,2007,342 (3-4):430-439.
    [8]Seyrek E, Dubin P L, Tribet C, et al. Ionic strength dependence of protein-polyelectrolyte interactions[J]. Biomacromolecules 2003,4 (2):273-282.
    [9]Roush D J, Gill D S, Willson R C. Electrostatic potentials and electrostatic interaction energies of rat cytochrome b5 and a simulated anion-exchange adsorbent surface[J]. Biophysical Journal,1994,66 (5):1290-1300.
    [10]Boura E, Hurley J H. Structural basis for membrane targeting by the MVB12-associated β-prism domain of the human ESCRT-IMVB12 subunit[J]. Proceedings of the National Academy of Sciences of the United States of America,2012,109 (6):1901-1906.
    [11]Ren Q H, Gorovsky M A. The nonessential H2A N-terminal tail can function as an essential charge patch on the H2A.Z variant N-terminal tail[J]. Molecular and Cellular Biology,2003,23 (8):2778-2789.
    [12]de Vries R, Weinbreck F, de Kruif C G. Theory of polyelectrolyte adsorption on heterogeneously charged surfaces applied to soluble protein-polyelectrolyte complexes[J]. The Journal of Chemical Physics,2003,118 (10):4649-4660.
    [13]Park J M, Muhoberac B B, Dubin P L, et al. Effect of protein charge heterogeneity in protein-polyelectrolyte complexation[J]. Macromolecules,1992,25 (1):290-295.
    [14]Grymonpre K R, Staggemeier B A, Dubin P L, et al. Identification by integrated computer modeling and light scattering studies of an electrostatic serum albumin-hyaluronic acid binding site[J]. Biomacromolecules,2001,2 (2):422-429.
    [15]Seyrek E, Dubin P L, Henriksen J. Nonspecific electrostatic binding characteristics of the heparin-antithrombin interaction[J]. Biopolymers,2007,86 (3):249-259.
    [16]Wiegel F W. Adsorption of a macromolecule to a charged surface[J]. Journal of Physics A:Mathematical and General,1977,10 (2):299-310.
    [17]Kong C Y, Muthukumar M. Monte carlo study of adsorption of a polyelectrolyte onto charged surfaces[J]. The Journal of Chemical Physics,1998,109 (4):1522-1528.
    [18]Evers O A, Fleer G J, Scheutjens J M H M, et al. Adsorption of weak polyelectrolytes from aqueous solution[J]. Journal of Colloid and Interface Science,1986,111 (2):446-454.
    [19]Mcquigg D W, Kaplan J I, Dubin P L. Critical conditions for the binding of polyelectrolytes to small oppositely charged micelles[J]. The Journal of Physical Chemistry, 1992,96(4):1973-1978.
    [20]Zhang H, Ohbu K, Dubin P L. Binding of carboxy-terminated anionic/nonionic mixed micelles to a strong polycation:critical conditions for complex formation[J]. Langmuir,2000, 16 (23):9082-9086.
    [21]Hong Y H, McClements D J. Formation of hydrogel particles by thermal treatment of β-lactoglobulin-chitosan complexes[J]. Journal of Agricultural and Food Chemistry,2007,55 (14):5653-5660.
    [22]Choi Y S, Kang D G, Lim S, et al. Recombinant mussel adhesive protein fp-5 (MAP fp-5) as a bulk bioadhesive and surface coating material [J]. Bio fouling:The Journal of Bioadhesion and Biofilm Research,2011,27 (7):729.
    [23]Aberkane L I, Jasniewski J, Gaiani C, et al. Thermodynamic characterization of acacia gum-β-lactoglobulin complex coacervation[J]. Langmuir,2010,26 (15):12523-12533.
    [24]Lenormand H, Deschrevel B, Tranchepain F, et al. Electrostatic interactions between hyaluronan and proteins at pH 4:How do they modulate hyaluronidase acitivity[J]. Biopolymers,2008,89 (12):1088-1103.
    [25]Kayitmazer B, Seeman D, Baykal B, et al. protein-polyelectrolyte interaction[J]. Soft Matter,2013,9,2553-2583.
    [26]Tang Z, Wang Y, Podsiadlo P, et al. Biomedical applications of layer-by-layer assembly: from biomimetics to tissue engineering[J]. Advanced Materials,2006,18 (24):3203-3224.
    [27]Kozlovskaya V, Kharlampieva E, Mansfield M L, et al. Poly(methacrylic acid) hydrogel films and capsules:response to pH and ionic strength, and encapsulation of macromolecules[J]. Chemistry Materials,2006,18 (2):328-336.
    [28]Dai J, Bao Z, Sun L, et al. High-capacity binding of proteins by poly(acrylic acid) brushes and their derivatives[J]. Langmuir,2006,22(9):4274-4281.
    [29]Yuan W, Dong H, Li C, et al. pH-controlled construction of chitosan/alginate multilayer film:characterization and application for antibody immobilization[J]. Langmuir,2007,23(26): 13046-13052.
    [30]Muller M, Kessler B, Houbenov N, et al. pH dependence and protein selectivity of poly(ethyleneimine)/poly(acrylic acid) multilayers studied by in situ ATR-FTIR spectroscopy[J]. Biomacromolecules,2006,7 (4):1285-1294.
    [31]Zhou X, Zhou J. Protein microarrays on hybrid polymeric thin films prepared by self-assembly of polyelectrolytes for multiple-protein immunoassays[J]. Proteomics,2006, 6(5):1415-1426.
    [32]Shutava T G, Kommireddy D S, Lvov Y M. Layer-by-layer enzyme/ polyelectrolyte films as a functional protective barrier in oxidizing media[J]. Journal of the American Chemical Society,2006,128 (30):9926-9934.
    [33]Xu Y, Mazzawi M, Chen K, et al. Protein purification by polyelectrolyte coacervation: influence of protein charge anisotropy on selectivity[J]. Biomacromolecules,2011,12 (5): 1512-1522.
    [34]Wang X, Wang Y W, Ruengruglikit C, et al. Effect on salt concentration on formation and dissociation of β-lactoglobulin/pectin complexes[J]. Journal of Agricultural and Food Chemistry,2007,55 (25):10432-10436.
    [35]Antonov M, Mazzawi M, Dubin P L. Entering and exiting the protein-polyelectrolyte coacervate phase via nonmonotonic salt dependence of critical conditions[J]. Biomacromolecules,2010,11 (1):51-59.
    [36]Ivanov A E, Nilsson L, Galaev I Y, et al. Boronate-containing polymers form affinity complexes with mucin and enable tight and reversible occlusion of mucosal iumen by polu(vinylalcohol) gel[J]. International Journal of Pharmaceutics,2008,358 (1-2):36-43.
    [37]Tan W S, Cohen R E, Rubner M F, et al. Temperature-induced, reversible swelling transitions in multilayers of a cationic triblock copolymer and a polyacid[J]. Macromolecules, 2010,43(4):1950-1957.
    [38]Kaibara K, Okazaki T, Bohidar H B, et al. pH-induced coacervation in complexes of bovine serum albumin and cationic polyelectrolytes[J]. Biomacromolecules,2000,1 (1): 100-107.
    [39]Kayitmazer A B, Strand S P, Tribet C, et al. Effect of polyelectrolyte structure on protein-polyelectrolyte coacervates:coacervates of bovine serum albumin with poly(diallyldimethylammonium chloride) versus chitosan[J]. Biomacromolecules,2007,8 (11):3568-3577.
    [40]Kim K, Cheng J, Liu Q, et al. Investigation of mechanical properties of soft hydrogel microcapsules in relation to protein delivery using a MEMs force sensor [J]. Journal of Biomedical Materials Research A,2010,92A(1):103-113.
    [41]Laos K, Parker R, Moffat J, et al. The adsorption of globular proteins, bovine serum albumin and (3-lactoglobulin, on poly-L-lysine-furcellaran multilayers [J]. Carbohydrate Polymers,2006,65 (3):235-242.
    [42]Liu H, Hu N. Interaction between myoglobin and hyaluronic acid in their layer-by-layer assembly:quartz crystal microbalance and cyclic voltammetry studies[J]. The Journal of Physical Chemistry B,2006,110 (29):14494-14502.
    [43]Crouzier T, Ren K, Nicolas C, et al. Layer-by-layer films as a biomimetic reservoir for rhBMP-2 delivery:controlled differentiation of myoblasts to osteoblasts[J]. Small 2009,5 (5): 598-608.
    [44]Lee H, Jeong Y, Park T G. Shell cross-linked hyaluronic acid/polylysine layer-by-layer polyelectrolyte microcapsules prepared by removal of reducible hyaluronic acid microgel cores[J]. Biomacromolecules,2007,8 (12):3705-3711.
    [45]Nel A E, Madler L, Velegol D, et al. Understanding biophysicochemical interactions at the nano-bio interface[J]. Nature Materials,2009,8,543-557.
    [46]Moyano D F, Rotello V M. Nano meets biology:structure and function at the nanoparticle interface[J]. Langmuir,2011,27 (17):10376-10385.
    [47]Cukalevski R, Lundqvist M, Oslakovic C, et al. Structural changes in apolipoproteins bound to nanoparticles[J]. Langmuir,2011,27 (23):14360-14369.
    [48]Dobrovolskaia M A, Germolec D R, Weaver J L. Evaluation of nanoparticle immunotoxicity[J]. Nature Nanotechnology,2009,4,411-414.
    [49]Xu X, Lenhoff A M. A predictive approach to correlating protein adsorption isotherms on ion-exchange media[J]. The Journal of Physical Chemistry B,2008,112 (3):1028-1040.
    [50]Klein J. Probing the interactions of proteins and nanoparticles[J]. Proceedings of the National Academy of Sciences of the United States of America,2007,104 (7):2029-2030.
    [51]Monopoli M P, Walczyk D, Campbell A, et al. Physical-chemical aspects of protein corona:relevance to in vitro and in vivo biological impacts of nanoparticles[J]. Journal of the American Chemical Society,2011,133 (8):2525-2534.
    [52]Caracciolo G, Pozzi D, Capriotti A L, et al. Evolution of the protein corona of lipid gene vectors as a function of plasma concentration[J]. Langmuir,2011,27 (24):15048-15053.
    [53]Casals E, Pfaller T, Duschl A, et al. Time evolution of the nanoparticle protein corona[J]. ACS Nano,2010,4 (7):3623-3632.
    [54]Lundqvist M, Stigler J, Cedervall T, et al. The evolution of the protein corona around nanoparticles:a test study [J]. ACS Nano,2011,5 (9):7503-7509.
    [55]Khandare J, Calderon M, Dagia N, et al. Multifunctional dendritic polymers in nanomedicine:opportunities and challenges[J]. Chemical Society Reviews,2012,41: 2824-2848.
    [56]Ganesan R, Kratz K, Lendlein A, Multicomponent protein patterning of material surfaces[J]. Journal of Materials Chemistry,2010,20 (35):7322-7331.
    [57]Scharnagl N, Lee S, Hiebl B, et al. Design principles for polymers as substratum for adherent cells[J]. Journal of Materials Chemistry,2010,20 (40):8789-8802.
    [58]Owens D E, Peppas N A. Opsonization, biodistribution, and pharmacokinetics of polymeric nanoparticles[J]. International Journal of Pharmaceutics,2006,307 (1):93-102.
    [59]Vroman L, Adams A L. Findings with the recording ellipsometer suggesting rapid exchange of specific plasma proteins at liquid/solid interfaces [J]. Surface Science,1969,16: 438-446.
    [60]Noh H, Vogler E A. Volumetric interpretation of protein adsorption:competition from mixtures and the vroman effect[J]. Biomaterials,2007,28 (3):405-422.
    [61]Fang F, Szleifer I. Molecular theoretical approach[J]. Biophysical Journal,2001,80 (6): 2568-2589.
    [62]Xia X R, Monteiro-Riviere N A, Riviere J E. An index for characterization of nanomaterials in biological systems[J]. Nature Nanotechnology,2010,5:671-675.
    [63]Treuel L, Nienhaus G U. Toward a molecular understanding of nanoparticle-protein interactions[J]. Biophysical Reviews,2012,4 (2):137-147.
    [64]Weber M. Bujotzek A, Andrae K, et al. Computational entropy estimation of linear polyether-modified surfaces and correlation with protein resistant properties of such surfaces[J]. Molecular Simulation,2011,37 (11):899-906.
    [65]Chen K, Xu Y, Rana S, et al. Electrostatic Selectivity in Protein-Nanoparticle Interactions[J]. Biomacromolecules,2011,12 (7):2552-2561.
    [66]Zhulina E B, Borisov O V. Structure and interaction of weakly charged polyelectrolyte brushes:self-consistent field theory[J]. The Journal of Chemical Physics,1997,107 (15): 5952-5967.
    [67]de Vos W M, Leermakers F A M, de Keizer A, et al. Field theoretical analysis of driving forces for the uptake of proteins by like-charged polyelectrolyte brushes:effect of charge regulation and patchiness[J]. Langmuir 2010,26 (1):249-259.
    [68]da Silva F L B, Lund M, Jonsson B, et al. On the complexation of proteins and polyelectrolytes[J]. The Journal of Physical Chemistry B,2006,110 (9):4459-4464.
    [69]de Vos W M, Biesheuvel P M, de Keizer A, et al. Adsorption of the protein bovine serum albumin in a planar poly(acrylic acid) brush layer as measured by optical reflectometry[J]. Langmuir,2008,24 (13):6575-6584.
    [70]Mattison K W, Dubin P L, Brittain I J. Complex formation between bovine serum albumin and strong polyelectrolytes:effect of polymer charge density[J]. The Journal of Physical Chemistry B,1998,102 (19):3830-3836.
    [71]Zhulina E B, Borisov O V. Poisson-boltzmann theory of pH-sensitive (annealing) polyelectrolyte brush[J]. Langmuir,2011,27 (17):10615-10633.
    [72]Carnal F, Stoll S. Adsorption of weak polyelectrolytes on charged nanoparticles. Impact of salt valency, pH, and nanoparticle charge density. Monte carlo simulations [J]. The Journal of Physical Chemistry B,2011,115(42):12007-12018.
    [73]Haupt B, Neumann Th, Wittemann A, et al. Activity of enzymes immobilized in colloidal spherical polyelectrolyte brushes[J]. Biomacromolecules,2005,6 (2):948-955.
    [74]Reichhart C, Czeslik C. Native-like structure of proteins at a planar poly(acrylic acid) brush[J]. Langmuir 2009,25 (2):1047-1053.
    [75]Wittemann A, Ballauff M. Temperature-induced unfolding of ribonuclease A embedded in spherical polyelectrolyte brushes[J]. Macromolecular Bioscience,2005,5 (1):13-20.
    [76]Henzler K, Wittemann A, Breininger E, et al. Adsorption of bovine hemoglobin onto spherical polyelectrolyte brushes monitored by small-angle x-ray scattering and fourier transform infrared spectroscopy[J]. Biomacromolecules,2007,8 (11):3674-3681.
    [77]Leermakers F A M, Ballauff M, Borisov O V. On the mechanism of uptake of globular proteins by polyelectrolyte brushes:A two-gradient self-consistent field analysis[J]. Langmuir, 2007,23 (7):3937-3946.
    [78]Uhlmann P. Houbenov N. Brenner N, et al. In-situ investigation of the adsorption of globular model proteins on stimuli-responsive binary polyelectrolyte brushes[J]. Langmuir, 2007,23(1):57-64.
    [79]Kusumo A, Bombalski L, Lin Q, et al. High capacity, charge-selective protein uptake by polyelectrolyte brushes[J]. Langmuir,2007,23(8):4448-4454.
    [80]Bittrich E, Rodenhausen K B, Eichhorn K J, et al. Protein adsorption on and swelling of polyelectrolyte brushes:a simultaneous ellipsometry-quartz crystal microbalance study[J]. Biointerphases,2010,5 (4):159-167.
    [81]Jain P, Dai J, Grajales S, et al. Completely aqueous procedure for the growth of polymer brushes on polymeric substrates[J]. Langmuir,2007,23 (23):11360-11365.
    [82]Betz M, Hormansperger J, Fuchs T, et al. Swelling behavior, charge and mesh size of thermal protein hydrogels as influenced by pH during gelation[J]. Soft Matter,2012,8: 2477-2485.
    [83]Goncalves C, Pereira P, Gama M. Self-assembled hydrogel nanoparticles for drug delivery applications[J]. Materials,2010,3 (2):1420-1460.
    [84]Kwon H J, Gong J P. Negatively charged polyelectrolyte gels as bio-tissue model system and for biomedical application[J]. Current Opinion in Colloid & Interface Science,2006,11 (6):345-350.
    [85]Kwon H J, Osada Y, Gong J P. Polyelectrolyte gels-fundamentals and applications!J]. Polymer Journal,2006,38:1211-1219.
    [86]Welsch N, Wittemann A, Ballauff M. Enhanced Activity of Enzymes Immobilized in Thermoresponsive Core-Shell Microgels [J]. The Journal of Physical Chemistry B,2009,113 (49):16039-16045.
    [87]Welsch N, Becker A L, Dzubiella J, et al. Core-shell microgel as "smart" carriers for enzymes[J]. Soft Matter,2012,8:1428-1436.
    [88]Herrwerth S, Eck W, Reinhardt S, et al. Factors that determine the protein resistance of oligoether self-assembled mono layers-internal hydrophilicity, terminal hydrophilicity, and lateral packing density[J]. Journal of the American Chemical Society,2003,125 (31): 9359-9366.
    [89]Heyes C D, Groll J, Moller M, et al. Synthesis, patterning and applications of star-shaped poly(ethylene glycol) biofunctionalized surfaces[J]. Molecular Biosystems,2007,3:419-430.
    [90]Borisov O V, Ballauff M. Polyelectrolyte brushes[J]. Current Opinion in Colloid & Interface Science,2006,11 (6):316-323.
    [91]Ballauff M. Spherical polyelectrolyte brushes[J]. Progress in Polymer Science,2007,32 (10):1135-1151.
    [92]Hollmann O, Czeslik C. Characterization of a planar poly(acrylic acid) brush as a materials coating for controlled protein immobilization[J]. Langmuir,2006,22 (7): 3300-3305.
    [93]Uhlmann P, Houbenov N, Brenner N, et al. In-situ investigation of the adsorption of globular model proteins on stimuli-responsive binary polyelectrolyte brushes[J]. Langmuir 2007,23(1):57-64.
    [94]Uhlmann P, Merlitz H, Sommer J U, et al. Polymer brushers for surface tuning[J]. Macromolecular Rapid Communications,2009,30 (9-10):732-740.
    [95]Wittemann A, Haupt B, Ballauff M. Adsorption of proteins on spherical polyelectrolyte brushes in aqueous solution[J]. Physical Chemistry Chemical Physics,2003,5:1671-1677.
    [96]Henzler K, Haupt B, Lauterbach K, et al. Adsorption of β-lactoglobulin on spherical polyelectrolyte brushes:direct proof of counterion release by isothermal titration calorimetry[J]. Journal of the American Chemical Society,2010,132 (9):3159-3163.
    [97]Becker A L, Welsch N, Schneider C, et al. Adsorption of RNase A on cationic polyelectrolyte brushes:a study by isothermal titration calorimetry[J]. Biomacromolecules, 2011,12 (11):3936-3944.
    [98]Lindman S, Lynch I, Thulin E, et al. Systematic investigation of the thermodynamics of HAS adsorption to N-iso-propylacrylamide/N-tert-butylacrylamide copolymer nanoparticles. Effect of particle size and hydrophobicity[J]. Nano Letters,2007,7 (4):914-920.
    [99]Cohen Stuart M A C, Huck W T S, Genzer J, et al. Emerging applications of stimuli-responsive polymer materials[J]. Nature Materials,2010,9:101-113.
    [100]Welsch N, Wittemann A, Ballauff M. Enhanced activity of enzymes immobilized in thermoresponsive core-shell microgels[J]. The Journal of Physical Chemistry B,2009,113 (49):16039-16045.
    [101]Lu Y, Ballauff M. Thermo sensitive core-shell microgels:from colloidal model systems to nanoreactors[J]. Progress in Polymer Science,2011,36 (6):767-792.
    [102]Fenley M O, Russo C, Manning G S. Theoretical assessment of the oligolysine model for ionic interactions in protein-DNA complexes[J]. The Journal of Physical Chemistry B, 2011,115 (32):9864-9872.
    [103]Becker A L, Henzler K, Welsch N, et al. Proteins and polyelectrolytes:a charged relationship[J]. Current Opinion in Colloid & Interface Science,2012,17 (2):90-96.
    [104]Wittemann A, Lu Y, Ballauff M. Supramolecular structures generated by spherical polyelectrolyte brushes and their application in catalysis[J]. Macromolecular Rapid Communications,2009,30 (9-10):806-815.
    [105]Lu Y, Ballauff M. "Smart" nanoparticles:preparation, characterization and applications[J]. Polymer,2007,48 (7):1815-1823.
    [106]Behrens S H, Borkovec M, Schurtenberger P. Aggregation in charge-stabilized colloidal suspensions revisited[J], Langmuir,1998,14(8):1951-1954.
    [107]Schneider C, Jusufi A, Farina R, et al. Stability behavior of anionic spherical polyelectrolyte brushes in the presence of La(Ⅲ) counterions[J]. Physical Review E,2010,82 (1):011401-011410.
    [108]Crassous J J, Siebenburger M, Ballauff M, et al. Thermosensitive core-shell particles as model systems for studying the flow behavior of concentrated colloidal dispersions[J]. Journal of Chemical Physics,2006,125 (20):204906-204916.
    [109]Crassous J J, Wittemann A, Siebenburger M, et al. Direct imaging of temperature-sensitive core-shell latexes by cryogenic transmission electron microscopy[J]. Colloid and Polymer Science,2008,286 (6-7):805-812.
    [110]Crassous J J, Rochette C N, Wittemann A, et al. Quantitative analysis of polymer colloids by cryo-transmission electron microscopy [J]. Langmuir,2009,25 (14):7862-7871.
    [111]Hoffmann M, Jusufi A, Schneider Ch, et al. Surface potential of spherical polyelectrolyte brushes in the presence of trivalent counterions[J]. Journal of Colloid and Interface Science,2009,338 (2):566-572.
    [112]Jimenez M L, Delgado A V, Ahualli S, et al. Giant permittivity and dynamic mobility observed for spherical polyelectrolyte brushes[J]. Soft Matter,2011,7:3758-3762.
    [113]Borisov O V, Birshtein T M, Zhulina E B. Polyelectrolyte molecule conformation near a charged surface[J]. Journal of Physics II (France) 1994,4 (6):913-929.
    [114]Pincus P. Colloid stabilization with grafted polyelectrolytes[J]. Macromolecules,1991, 24 (10):2912-2919.
    [115]Biesheuvel P M, Wittemann A. Amodified box model including charge regulation for protein adsorption in spherical polyelectrolyte brush[J]. The Journal of Physical Chemistry B, 2005,109 (9):4209-4214.
    [116]de Vos W M, Biesheuvel P M, de Keizer A, et al. Adsorption of the protein bovine serum albumin in a planar poly(acrylic acid) brush layer as measured by optical reflectomtry[J]. Langmuir 2008,24 (13):6575-6584.
    [117]Wittemann A, Ballauff M. Interaction of proteins with linear polyelectrolytes and spherical polyelectrolyte brushes in aqueous solution[J]. Physical Chemistry Chemical Physics,2006,8:5269-5275.
    [118]Currie E P K, Van der Gucht J, Borisov O V, et al. Stuffed brushes:theory and experiment [J]. Pure Applied Chemistry,1999,71 (7):1227-1241.
    [119]Kokufuta E, Shimizu H, Nakamura I. Stoichiometric complexation of human serum albumin with strongly acidic and basic polyelectrolytes[J]. Macromolecules,1982,15 (6): 1618-1621.
    [120]Xia J, Dubin P L. Protein-polyelectrolyte complexes[J]. Macromolecular Complexes in Chemistry and Biology,1994:247-271.
    [121]Serefoglou E, Oberdisse J, Staikos G. Characterization of the soluble nanoparticles formed through coulombic interaction of bovine serum albumin with anionic graft copolymers at low pH[J]. Biomacromolecules,2007,8 (4):1195-1199.
    [122]Tikhonenko S A, Saburova E A, Durdenko E N, et al. Enzyme-polyelectrolyte complex: salt effects on the reaction of urease with polyallylamine[J]. Russian Journal of Physical Chemistry A,2009,83 (10):1781-1788.
    [123]Xu Y, Seeman D, Yan Y, et al. Effect of heparin on protein aggregation:inhibition versus promotion[J]. Biomacromolecules,2012,13 (5):1642-1651.
    [124]Boeris V, Micheletto Y, Lionzo M, et al. Interaction behavior between chitosan and pepsin[J]. Carbohydrate Polymers,2011,84 (1):459-464.
    [125]Ball V, Maechling C. Isothermal microcalorimetry to investigate non specific interactions in biophysical chemistry[J]. International Journal of Molecular Sciences,2009, 10:3283-3315.
    [126]Hsu C, Lin H, Thomas J L, et al. The microcontact imprinting of proteins:the effect of cross-linking monomers for lysozyme, ribonuclease A and myoglobin[J]. Biosensors and Bioelectronics.2006,22 (4):534-543.
    [127]Baier G, Costa C, Zeller A, et al. BSA adsorption on differently charged polystyrene nanoparticles using isothermal titration calorimetry and the influence on cellular uptake[J]. Macromolecular Bioscience,2011,11 (5):628-638.
    [128]Romanini D, Braia M, Angarten R G, et al. Interaction of lysozyme with negatively charged flexible chain polymers[J]. Journal of Chromatography B,2007,857 (1):25-31.
    [129]Braia M, Porfiri M C, Farruggia B, et al. Complex formation between protein and poly vinyl sulfonate as a strategy of proteins isolation[J]. Journal of Chromatography B,2008,873 (2):139-143.
    [130]Braia M, Tubio G, Nerli B, et al. Analysis of the interactions between eudragit(?)L100 and porcine pancreatic trypsin by calorimetric techniques [J]. International Journal of Biological Macromolecules,2012,50 (1):180-186.
    [131]Channasanon S, Graisuwan W, Kiatkamjornwong S, et al. Alternation bioactivity of multilayer thin films assembled from charged derivatives of chitosan[J]. Journal of Colloid and Interface Science,2007,316 (2):331-343.
    [132]Mao S, Bakowsky U, Jintapattanakit A, et al. Self-assembled polyelectrolyte nanocomplexes between chitosan derivatives and insulin[J]. Journal of Pharmaceutical Sciences,2006,95 (5):1035-1048.
    [133]Olanya G, Thormann E, Varge I, et al. Protein interactions with bottle-brush polymer layers:effect of side chain and charge density ratio probed by QCM-D and AFM[J]. Journal of Colloid and Interface Science,2010,349 (1):265-274.
    [134]Fan Y, Wang Y, Fan Y, et al. Preparation of insulin nanoparticles and their encapsulation with biodegradable polyelectrolytes via the layer-by-layer adsorption[J]. International Journal of Pharmaceutics,2006,324 (2):158-167.
    [135]Winzor D J. Determination of binding constants by analogous procedures in size exclusion chromatography and capillary electrophoresis[J]. Analytical Biochemistry,2008, 383:1-17.
    [136]McKeon J, Holland L A. Determination of dissociation constants for a heparin-binding domain of amyloid precursor protein and heparins or heparin sulfate by affinity capillary electrophoresis[J]. Electrophoresis,2004,25 (9):1243-1248.
    [137]Preising M N, Heegard S. Recent advances in early-onset severe retinal degeneration: more than just basic research?[J]. Trends in Molecular Medicine,2004,10 (2):51-54.
    [138]Anderot M, Nilsson M, Vegvari A, et al. Determination of dissociation constants between polyelectrolytes and proteins by affinity capillary electrophoresis[J]. Journal of Chromatography B,2009,877 (10):892-896.
    [139]Gao J Y, Dubin P L, Muhoberac B B. Measurement of the binding of proteins to polyelectrolytes by frontal analysis continuous capillary electrophoresis[J]. Analytical Chemistry,1997,69 (15):2945-2951.
    [140]Johnson W C. Protein secondary structure and circular dichroism:a practical guide[J]. Proteins,1990,7 (3):205-214.
    [141]Shu S, Zhang X, Wu Z, et al. Gradient cross-linked biodegradable polyelectrolyte nanocapsules for intracellular protein drug delivery[J]. Biomaterials,2010,31 (23): 6039-6049.
    [142]Yoshida K, Sato K, Anzai J. Layer-by-layer polyelectrolyte films containing insulin for pH-triggered release[J]. Journal of Materials Chemistry,2010,20 (8):1546-1552.
    [143]Sperber B L H M, Cohen Stuart M A, Schols H A, et al. Binding of β-lactoglobulin to pectins varying in their overall and local charge density[J]. Biomacromolecules,2009,10 (12): 3246-3252.
    [144]Kudryashova E V, Visser A J W G, van Hoek A, et al. Molecular details of ovalbumin-pectin complexes at the air/water interface:a spectroscopic study[J]. Langmuir, 2007,23 (15):7942-7950.
    [145]Antonov Y A, Moldenaers P. Structure formation and phase-separation behavior of aqueous casein-alginate emulsions in the presence of strong polyelectrolyte[J]. Food Hydrocolloids,2011,25 (3):350-360.
    [146]Ladd J, Zhang Z, Chen S, et al. Zwitterionic polymers exhibiting high resistance to nonspecific protein adsorption from human serum and plasma[J]. Biomacromolecules,2008, 9(5):1357-1361.
    [147]Ayres N, Holt D J, Jones C F, et al. Polymer brushes containing sulfonated sugar repeat units:synthesis, characterization, and in vitro testing of blood coagulation activation[J]. Journal of Polymer Science Part A:Polymer Chemistry,2008,46 (23):7713-7724.
    [148]Zhulina E B, Leermakers F A M. On the polyelectrolyte brush model of neurofilaments[J]. Soft Matter,2009,5:2836-2840. [149] Li F, Park S, Ling D, et al. Hyaluronic acid-conjugated grapheme oxide/photosensitizer nanohybrids for cancer targeted photodynamic therapy[J]. Journal of Materials Chemistry B, 2013,1,1678-1686.
    [150]Giger K, Vanam R P, Seyrek E, et al. Suppression of insulin aggregation by heparin[J]. Biomacromolecules,2008,9 (9):2338-2344.
    [151]Chung K, Kim J, Cho B, et al. How does dextran sulfate prevent heat induced aggregation of protein?:The mechanism and its limitation as aggregation inhibitor[J] Biochimica et Biophysica Acta (BBA)-Proteins and Proteomics,2007,1774 (2):249-257.
    [152]Stogov S, Muronets V, Izumrudov V. Basic guidelines for the selection of polyelectrolytes that can effectively prevent thermal aggregation of enzymes without any substantial loss in their catalytic activity[J]. Polymer Science Series C,2011,53 (1):97-106.
    [153]Sedlak E, Fedunova D, Vesela V, et al. Polyanion hydrophobicity and protein basicity affect protein stability in protein-polyanion complexes[J]. Biomacromolecules,2009,10 (9): 2533-2538.
    [154]Zhange H, Saiani A, Guenet J, et al. Effect of stereoregular polyelectrolyte on protein thermal stability[J]. Macromolecular Symposia,2007,251 (1):25-32.
    [155]Lu Y, Wittemann A, Ballauff M. Supramolecular structures generated by spherical polyelectrolyte brushes and their application in catalysis[J]. Macromolecular Rapid Communications,2009,30 (9-10):806-815.
    [156]Veselova I, Kireiko A, Shekhovtsova T. Catalytic acitivity and the stability of horseradish peroxidase increase as a result of its incorporation into a polyelectrolyte complex with chitosan[J]. Applied Biochemistry and Microbiology,2009,45 (2):125-129.
    [157]Marin A, DeCollibus D P, Andrianov A K. Protein stabilization in aqueous solutions of polyphosphazene polyelectrolyte and non-ionic surfactants [J]. Biomacromolecules,2010,11 (9):2268-2273.
    [158]Holler C, Zhang C. Purification of an acidic recombinant protein from transgenic tobacco[J]. Biotechnology Bioengineering,2008,99 (4):902-909.
    [159]Zhang C, Lillie R, Cotter J, et al. Lysozyme purification from tobacco extract by polyelectrolyte precipitation[J]. Journal of Chromatography A,2005,1069 (1):107-112.
    [160]Li X, Xie Q, Zhang J, et al. The packaging of siRNA within the mesoporous structure of silica nanoparticles[J]. Biomaterials,2013,34,1391-1401.
    [161]Leclercq S, Milo C, Reineccius G A. Effects of cross-linking, capsule wall thickness, and compound hydrophobicity on aroma release form complex coacervate microcapsules[J]. Journal of Agricultural and Food Chemistry,2009,57,1426.
    [162]Bayes-Garcia L, Ventola L, Cordobilla R, et al. Phase change materials (PCM) microcapsules with different shell compositions:preparation, characterization and thermal stability[J]. Solar Energy Materials and Solar Cells,2010,94 (7):1235-1240.
    [163]Shao H, Weerasekare G M, Stewart R J. Controlled curing of adhesive complex coacervates with reversible periodate carbohydrate complexes[J]. Journal of Bio medical Materials Research (Part A),2011,97A (1):46-51.
    [1]Henzler K, Wittemann A, Breininger E, et al. Adsortpion of bovine hemoglobin onto spherical polyelectrolyte brushes monitored by small-angle X-ray scattering and fourier transform infrared spectroscopy[J]. Biomacromolecules,2007,8(11):3674-3681.
    [2]Czeslik C. Factors ruling protein adsorption[J]. Zeitschrift for Physical Chemistry,2004, 218(7):771-801.
    [3]Welsch N, Becker A L, Dzubiella J, et al. Core-shell microgels as "smart" carriers for enzymes[J]. Soft Matter,2012,8(5):1428-1436.
    [4]Haupt B, Neumann Th, Wittemann A, et al. Activity of enzymes immobilized in colloidal spherical polyelectrolyte brushes[J]. Biomacromolecules,2005,6(2):948-955.
    [5]Wittemann A, Ballauff M. Secondary structure analysis of proteins embedded in spherical polyelectrolyte brushes by FT-IR spectroscopy[J]. Analytical Chemistry,2004,76(10): 2813-2819.
    [6]Anikin K, Rocker C, Wittemann A, et al. Polyelectrolyte-mediated protein adsorption: fluorescent protein binding to individual polyelectrolyte nanospheres[J]. The Journal of Physical Chemistry B,2005,109(12):5418-5420.
    [7]Wittemann A, Ballauff M. Interaction of proteins with linear polyelectrolytes and spherical polyelectrolyte brushes in aqueous solution [J]. Physical Chemistry Chemical Physics,2006, 8(45):5269-5275.
    [8]Guo X, Weiss A. Ballauff M. Synthesis of spherical polyelectrolyte brushes by photoemulsion polymerization[J]. Macromolecules,1999,32(19):6043-6046.
    [9]Guo X, Ballauff M. Spatial dimensions of colloidal polyelectrolyte brushes as determined by dynamic light scattering [J]. Langmuir,2000,16(23):8719-8726.
    [10]Wang X, Wu S, Li L, et al. Synthesis of spherical polyelectrolyte brushes by photoemulsion polymerization with different photo initiators [J]. Industrial & Engineering Chemistry Research,2011,50(6):3564-3569.
    [11]Hoffmann M, Jusufi A, Schneider C, et al. Surface potential of spherical polyelectrolyte brushes in the presence of trivalent counterions[J]. Journal of Colloid and Interface Science, 2009,338(2):566-572.
    [12]Schneider C, Jusufi A, Farina R, et al. Stability behavior of anionic spherical polyelectrolyte brushes in the presence of La(III) counterions[J]. Physical Review E,2010, 82(1):011401-011411.
    [13]Jimenez M L, Delgado A V, Ahualli S, et al. Giant permittivity and dynamic mobility observed for spherical polyelectrolyte brushes[J]. Soft Matter,2011,7(8):3758-3762.
    [14]Henzler K, Haupt B, Lauterbach K, et al. Adsorption of β-lactoglobulin on spherical polyelectrolyte brushes:direct proof of counterion release by isothermal titration calorimetry[J]. Journal of American Chemical Society,2010,132(9):3159-3163.
    [15]Becker A L, Welsch N, Schneider C, et al. Adsorption of RNase A on cationic polyelectrolyte brushes:a study by isothermal titration calorimetry[J]. Bio macro molecules, 2011,12(11):3936-3944.
    [16]Welsch N, Dzubiella J, Graebert A, et al. Protein binding to soft polymeric layers:a quantitative study by fluorescence spectroscpy[J]. Soft Mater,2012,8(48):12043-12052.
    [17]Yigit C, Welsch N, Ballauff M, et al. Protein sorption to charged microgels: characterizing binding isotherms and driving forces[J]. Langmuir,2012,28(40): 14373-14385.
    [18]Dingenouts N, Bolze J, Potschke D, et al. Analysis of polymer latexes by small-angle X-ray scattering [J]. Advances in Polymer Science,1999,144,1-47.
    [19]Rosenfeldt S, Wittemann A, Ballauff M, et al. Interaction of proteins with spherical polyelectrolyte brushes in solution as studied by small-angle x-ray scattering[J]. Physical Review E,2004,70(6):061403-061412.
    [20]Henzler K, Rosenfeldt S, Wittemann A, et al. Directed motion of proteins along tethered polyelectrolytes[J]. Physical Review Letters,2008,100(15):158301-158304.
    [21]Henzler K, Haupt B, Rosenfeldt S, et al. Interaction strength between proteins and polyelectrolyte brushes:a small angle X-ray scattering study [J]. Physical Chemistry Chemical Physics,2011,13(39):17599-17605.
    [22]Guo X, Kirton G F, Dubin P L. Carboxylated ficolls:preparation, characterization, and electrophoretic behavior of model charged nanospheres[J]. The Journal of Physical Chemistry B,2006,110(42):20815-20822.
    [23]Guo X, Ballauff M. Spherical polyelectrolyte brushes:comparison between annealed and quenched brushes[J]. Physical Review E,2001,64(5):051406-051414.
    [24]Ballauff M, Borisov O. Polyelectrolyte brushes[J]. Current Opinion in Colloid & Interface Science,2006,11(6):316-323.
    [25]Xia J, Dubin P L, Dautzenberg H. Light scattering, electrophoresis, and turbidimetry studies of bovine serum albumin-poly(dimethyldiallylammonium chloride) complex[J]. Langmuir,1993,9(8):2015-2019.
    [26]Hattori T, Hallberg R, Dubin P L. Roles of electrostatic interaction and polymer structure in the binding of β-lactoglobulin to anionic polyelectrolytes:measurement of binding constants by frontal analysis continuous capillary electrophoresis[J]. Langmuir,2000,16(25): 9738-9743.
    [27]Li Y, Xia J, Dubin P L. Complex formation between polyelectrolyte and oppositely charged mixed micelles:static and dynamic light scattering study of the effect of polyelectrolyte molecular weight and concentration[J]. Macromolecules,1994,27(24): 7049-7055.
    [28]Mattison K W, Dubin P L, Brittain I J. Complex formation between bovine serum albumin and strong polyelectrolytes:effect of polymer charge density[J]. The Journal of Physical Chemistry B,1998,102(19):3830-3836.
    [29]da Silvar F L B, Lund M, Jonsson B. et al. On the complexation of proteins and polyelectrolyte[J]. The Journal of Physical Chemistry B,2006,110(9):4459-4464.
    [30]Kayitmazer A B, Strand S P, Tribet C, et al. Effect of polyelectrolyte structure on protein-polyelectrolyte coacervates:coacervates of bovine serum albumin with poly(diallyldimethylammonium chloride) versus chitosan[J]. Biomacromolecules,2007,8(11): 3568-3577.
    [31]Antonov M, Mazzawi M, Dubin P L. Entering and exiting the protein-polyelectrolyte coacervate phase via nonmonotonic salt dependence of critical conditions [J]. Biomacromolecules,2010,11(1):51-59.
    [32]Mattison K. M, Brittain I J, Dubin P L. Protein-polyelectrolyte phase boundaries[J]. Biotechnology Progress,1995,11(6):632-637.
    [33]Leermakers F A M, Ballauff M, Borisov O V. On the mechanism of uptake of globular proteins by polyelectrolyte brushes:a two-gradient self-consistent field analysis[J]. Langmuir, 2007,23(7):3937-3946.
    [34]Wittemann A, Haupt B, Ballauff M. Controlled release of proteins bound to spherical polyelectrolyte brushes[J]. Zeitschrift for Physical Chemistry,2007,221(1):113-126.
    [35]De M, You C C, Srivastava S. et al. Biomimetic interactions of proteins with functionalized nanoparticles:a thermodynamic study [J]. Journal of American Chemical Society,2007,129,10747-10753.
    [36]De M, Miranda O R, Rana S. et al. Size and geometry dependent protein-nanoparticle self-assembly[J]. Chemical Communications,2009,16:2157-2159.
    [37]Silva R A, Urzua M D, Petri D F S, et al. Protein adsorption onto polyelectrolyte layers: effects of protein hydrophobicity and charge anisotropy[J]. Langmuir,2010,26(17): 14032-14038.
    [1]Senaratne W, Andruzzi L, Ober C K. Self-assembled monolayers and polymer brushes in biotechnology:current applications and future perspectives[J]. Biomacromolecules,2005, 6(5):2427-2448.
    [2]Czeslik C. Factors ruling protein adsorption[J]. Zeitschrift for Physical Chemistry,2004, 218(7):771-801.
    [3]Xu Z, Feng Y, Liu X, et al. Synthesis and characterization of Fe3O4@SiO2@ poly-L-alanine, peptide brush-magnetic microspheres through NCA chemistry for drug delivery and enrichment of BSA[J]. Colloids and Surfaces B:Biointerfaces,2010,81(2): 503-507.
    [4]Slouf M, Hruby M, Bakaeva Z, et al. Preparation of stable Pd nanocubes and their use in biological labeling[J]. Colloids and Surfaces B:Biointerfaces,2012,100(1):205-208.
    [5]Barua S, Konwarh R, Bhattacharya S S, et al. Non-hazardous anticancerous and antibacterial colloidal "green" silver nanoparticles[J]. Colloids and Surfaces B:Biointerfaces, 2013,105(1):37-42.
    [6]Reichhart C, Czeslik C. Native-like structure of proteins at a planar poly(acrylic acid) brush[J]. Langmuir,2009,25(2):1047-1053.
    [7]Hollmann O, Steitz R, Czeslik C. Structure and dynamics of a-lactalbumin adsorbed at a charged brush interface[J]. Physical Chemistry Chemical Physics,2008,10(10):1448-1456.
    [8]Czeslik C, Jackler G, Hazlett T, et al. Salt-induced protein resistance of polyelectrolyte brushes studied using fluorescence correlation spectroscopy and neutron reflectometry[J]. Physical Chemistry Chemical Physics,2004,6(24):5557-5563.
    [9]Kusumo A, Bombalski L, Lin Q, et al. High capacity, charge-selective protein uptake by polyelectrolyte brushes[J]. Langmuir,2007,23(8):4448-4454.
    [10]de Vos W M, Leermakers F A M, de Keizer A, et al. Field theoretical analysis of driving forces for the uptake of proteins by like-charged polyelectrolyte brushes:effects of charge regulation and patchiness[J]. Langmuir,2010,26(1):249-259.
    [11]Henzler K, Wittemann A, Breininger E, et al. Adsortpion of bovine hemoglobin onto spherical polyelectrolyte brushes monitored by small-angle X-ray scattering and fourier transform infrared spectroscopy[J]. Biomacromolecules,2007,8(11):3674-3681.
    [12]Welsch N, Becker A L, Dzubiella J, et al. Core-shell microgels as "smart" carriers for enzymes[J]. Soft Matter,2012,8(5):1428-1436.
    [13]Haupt B, Neumann Th, Wittemann A, et al. Activity of enzymes immobilized in colloidal spherical polyelectrolyte brushes[J]. Biomacromolecules,2005,6(2):948-955.
    [14]Wittemann A, Ballauff M. Secondary structure analysis of proteins embedded in spherical polyelectrolyte brushes by FT-IR spectroscopy[J]. Analytical Chemistry,2004, 76(10):2813-2819.
    [15]Anikin K, Rocker C, Wittemann A, et al. Polyelectrolyte-mediated protein adsorption: fluorescent protein binding to individual polyelectrolyte nanospheres[J]. The Journal of Physical Chemistry B,2005,109(12):5418-5420.
    [16]Guo X, Weiss A. Ballauff M. Synthesis of spherical polyelectrolyte brushes by photoemulsion polymerization[J]. Macromolecules,1999,32(19):6043-6046.
    [17]Guo X, Ballauff M. Spatial dimensions of colloidal polyelectrolyte brushes as determined by dynamic light scattering[J]. Langmuir,2000,16(23):8719-8726.
    [18]Wang X, Wu S, Li L, et al. Synthesis of spherical polyelectrolyte brushes by photoemulsion polymerization with different photoinitiators [J]. Industrial & Engineering Chemistry Research,2011,50(6):3564-3569.
    [19]Schrinner M, Proch S, Mei Y, et al. Stable bimetallic gold-platinum nanoparticles immobilized on spherical polyelectrolyte brushes:synthesis, characterization, and application for the oxidation of alcohols[J]. Advanced Materials,2008,20(10):1928-1933.
    [20]Schrinner M, Ballauff M, Talmon Y, et al. Single nanocrystals of platinum prepared by partial dissolution of Au-Pt nanoalloys[J]. Science,2009,323(5914):617-620.
    [21]Sharma G, Ballauff M. Cationic spherical polyelectrolyte brushes as nanoreactors for the generation of gold particles[J]. Macromolecular Rapid Communications,2004,25(4): 547-552.
    [22]Mei Y, Sharma G, Lu Y, et al. High catalytic activity of platinum nanoparticles immobilized on spherical polyelectrolyte brushes[J]. Langmuir,2005,21(26):12229-12234.
    [23]Mei Y, Ballauff M. Effect of counterions on the swelling of spherical polyelectrolyte brushes[J]. The European Physical Journal E,2005,16(3):341-349.
    [24]Volk N, Vollmer D, Schmidt M, et al. Conformation and phase diagrams of flexible polyelectrolytes[J]. Advances in Polymer Science,2004,166:29-65.
    [25]Wang S, Chen K, Li L, et al. Binding between proteins and cationic spherical polyelectrolyte brushes:effect of pH, ionic strength, and stoichiometry[J]. Biomacromolecules,2013,14(3):818-827.
    [26]Wang S, Chen K, Kayitmazer A B, et al. Tunable adsorption of bovine serum albumin by annealed cationic spherical polyelectrolyte brushes[J]. Colloids and Surfaces B:Bio interfaces, 2013,107(1):251-256.
    [27]De M, You C C, Srivastava S. et al. Biomimetic interactions of proteins with functionalized nanoparticles:a thermodynamic study[J]. Journal of American Chemical Society,2007,129,10747-10753.
    [28]Mattison K M, Brittain I J, Dubin P L. Protein-polyelectrolyte phase boundaries[J]. Biotechnology Progress,1995,11(6):632-637.
    [29]Silva R A, Urzua M D, Petri D F S, et al. Protein adsorption onto polyelectrolyte layers: effects of protein hydrophobicity and charge anisotropy[J]. Langmuir,2010,26(17): 14032-14038.
    [30]Wittemann A, Ballauff M. Interaction of proteins with linear polyelectrolytes and spherical polyelectrolyte brushes in aqueous solution [J]. Physical Chemistry Chemical Physics,2006,8(45):5269-5275.
    [31]Rosenfeldt S, Wittemann A, Ballauff M, et al. Interaction of proteins with spherical polyelectrolyte brushes in solution as studied by small-angle x-ray scattering[J]. Physical Review E,2004,70(6):061403-061412.
    [1]Haupt B, Neumann Th, Wittemann A, et al. Activity of enzymes immobilized in colloidal spherical polyelectrolyte brushes[J]. Biomacromolecules,2005,6(2):948-955. [2] Wittemann A, Ballauff M. Secondary structure analysis of proteins embedded in spherical polyelectrolyte brushes by FT-IR spectroscopy[J]. Analytical Chemistry,2004,76(10): 2813-2819.
    [3]Henzler K, Wittemann A, Breininger E, et al. Adsortpion of bovine hemoglobin onto spherical polyelectrolyte brushes monitored by small-angle X-ray scattering and fourier transform infrared spectroscopy[J]. Biomacromolecules,2007,8(11):3674-3681.
    [4]Anikin K, Rocker C, Wittemann A, et al. Polyelectrolyte-mediated protein adsorption: fluorescent protein binding to individual polyelectrolyte nanospheres[J]. The Journal of Physical Chemistry B,2005,109(12):5418-5420.
    [5]Becker A L, Welsch N, Schneider C, et al. Adsorption of RNase A on cationic polyelectrolyte brushes:a study by isothermal titration calorimetry[J]. Biomacromolecules, 2011,12(11):3936-3944.
    [6]Wittemann A, Ballauff M. Temperature-induced unfolding of ribonuclease A embedded in spherical polyelectrolyte brushes[J]. Macromolecular Bioscience,2005,5(1):13-20.
    [7]De M, Miranda O R, Rana S, et al. Size and geometry dependent protein-nanoparticle self-assembly[J]. Chemical Communications,2009, (16):2157-2159.
    [8]Kayitmazer B, Seeman D, Baykal B, et al. Protein-polyelectrolyte interactions[J]. Soft Matter,2013,9(9):2553-2583.
    [9]Kayitmazer A B, Strand S P, Tribet C, et al. Effect of polyelectrolyte structure on protein-polyelectrolyte coacervates:coacervates of bovine serum albumin with poly(diallyldimethylammonium chloride) versus chitosan[J]. Biomacromolecules,2007,8(11): 3568-3577.
    [10]Kayitmazer B, Quinn B, Kimura K, et al. Protein specificity of charged sequences in polyanions and heparins[J]. Biomacromolecules,2010,11(12):3325-3331.
    [11]Seyrek E, Dubin P L, Tribet C, et al. Ionic strength dependence of protein-polyelectrolyte interactions[J]. Biomacromolecules,2003,4(2):273-282.
    [12]Silva R A, Urzua M D, Petri D F S, et al. Protein adsorption onto polyelectrolyte layers: effects of protein hydrophobicity and charge anisotropy[J]. Langmuir,2010,26(17): 14032-14038.
    [13]Antonov M, Mazzawi M, Dubin P L, Entering and exiting the protein-polyelectrolyte coacervate phase via nonmonotonic salt dependence of critical conditionsfJ]. Biomacromolecules,2010,11(1):51-59.
    [14]Biesheuvel P M, Wittemann A. A modified box model including charge regulation for protein adsorption in a spherical polyelectrolyte brush[J]. The Journal of Physical Chemistry B,2005,109(9):4209-4214.
    [15]Biesheuvel P M, Leermakers F A M, Cohen Stuart M A. Self-consistent field theory of protein adsorption in a non-Gaussian polyelectrolyte brush[J]. Physical Review E,2006,73(1): 011802-011810.
    [16]Leermakers F A M, Ballauff M, Borisov O V. On the mechanism of uptake of globular proteins by polyelectrolyte brushes:a two-gradient self-consistent field analysis[J]. Langmuir, 2007,23(7):3937-3946.
    [17]Xu Y, Seeman D, Yan Y, et al. Effect of heparin on protien aggregation:inhibition versus promotion[J]. Biomacromolecules,2012,13,1642-1651.
    [18]Xu Y, Engel Y, Yan Y, et al. Enhanced electrostatic discrimination of proteins on nanoparticle-coated surfaces[J]. Journal of Materials Chemistry B,2013 (DOI:10.1039)
    [19]Chen K, Xu Y, Rana S, et al. Electrostatic selectivity in protein-nanoparticle interactions[J]. Biomacromolecules,2011,12(7):2552-2561.
    [20]Xu Y, Mazzawi M, Chen K, et al. Protein puridication by polyelectrolyte coacervation: influence of protein charge anisotropy on selectivity[J]. Biomacromolecules,2011,12(5): 1512-1522.
    [21]Majhi P R, Ganta R R, Vanam R P, et al. Electrostatically driven protein aggregation:β-lactoglobulin at low ionic strength[J]. Langmuir,2006,22(22):9150-9159.
    [22]Henzler K, Haupt B, Lauterbach K, et al. Adsorption of β-lactoglobulin on spherical polyelectrolyte brushes:direct proof of counterion release by isothermal titration calorimetry[J]. Journal of the American Chemical Society,2010,132(9):3159-3163.
    [23]De M, You C C, Srivastava S, et al. Biomimetic interactions of proteins with functionalized nanoparticles:a thermodynamic study[J]. Journal of the American Chemical Society,2007,129(35):10747-10753.
    [1]Henzler K, Wittemann A, Breininger E, et al. Adsorption of bovine hemoglobin onto spherical polyelectrolyte brushes monitored by small-angle X-ray scattering and fourier transform infrared spectroscopy[J]. Biomacromolecules,2007,8(11):3674-3681.
    [2]Czeslik C. Factors ruling protein adsorption[J]. Zeitschrift for Physikalische Chemie,2004, 218(7):771-801.
    [3]Guo X, Ballauff M. Spatial dimensions of colloidal polyelectrolyte brushes as determined by dynamic light scattering[J]. Langmuir,2000,16(23):8719-8726.
    [4]Guo X, Ballauff M. Spherical polyelectrolyte brushes:comparison between annealed and quenched brushes[J]. Physical Review E,2001,64(5) 051406-051414.
    [5]Ballauff M, Borisov O. Polyelectrolyte brushes[J]. Current Opinion in Colloid & Interface Science,2006,11(6):316-323.
    [6]Ballauff M. Spherical polyelectrolyte brushes[J]. Progress in Polymer Science,2007, 32(10):1135-1151.
    [7]Chen K, Zhu Y, Zhang Y, et al. Synthesis of magnetic spherical polyelectrolyte brushes[J]. Macromolecules,2011,44(3):632-639.
    [8]Chen K, Zhu Y, Li L, et al. Recyclable spherical polyelectrolyte brushes containing magnetic nanoparticles in core[J].Macromolecular Rapid Communications,2010,31, 1440-1443.
    [9]Wu S, Kaiser J, Guo X, et al. Recoverable platinum nanocatalysts immobilized on magnetic spherical polyelectrolyte brushes[J]. Industrial & Engineering Chemistry Research, 2012,51(15):5608-5614.
    [10]Henzler K, Haupt B, Ballauff M. Enzymatic activity of immobilized enzyme determined by isothermal titration calorimetry[J]. Analytical Biochemistry,2008,378,184-189.
    [11]Welsch N, Wittemann A, Ballauff M. Enhanced activity of enzymes immobilized in thermoresponsive core-shell microgels[J]. The Journal of Physical Chemistry B,2009,113, 16039-16045.
    [12]Haupt B, Neumann Th, Wittemann A, et al. Activity of enzymes immobilized in colloidal spherical polyelectrolyte brushes[J]. Biomacromolecules,2005,6,948-955.
    [13]Lu Y, Ballauff M. Thermosensitive core-shell microgels:from colloidal model systems to nanoreactors[J]. Progress in Polymer Science,2011,36(6):767-792.
    [14]Sharma G, Ballauff M. Cationic Spherical Polyelectrolyte Brushes as Nanoreactors for the Generation of Gold Particles[J]. Macromolecular Rapid Communications,2004,25, 547-552.
    [15]Lu Y, Wittemann A, Ballauff M. Supramolecular Structures Generated by Spherical Polyelectrolyte Brushes and their Application in Catalysis[J]. Macromolecular Rapid Communications,2009,30(9-10):806-815.
    [16]Mei Y, Sharma G, Lu Y, Ballauff M, Drechsler M, Irrgang T, et al. High Catalytic Activity of Platinum Nanoparticles Immobilized on Spherical Polyelectrolyte Brushes[J]. Langmuir,2005,21(26):12229-12234.
    [17]Welsch N, Lu Y, Dzubiella J, et al. Adsorption of proteins to functional polymeric nanoparticles[J]. Polymer,2013, DOI:10.1016.
    [18]Gerhartz W. Enzymes in industry:production and applications[B].1990,321.
    [19]Bernfeld P. Amylases, alpha and beta[J]. Methods in Enzymology,1955:149-158.
    [20]Sheldon R A. Enayme immobilization:the quest for optimum performance[J]. Advanced Synthesis & Catalysis,2007,349(8-9):1289-1307.
    [21]Varavinit S, Chaokasem N, Shobsngob S. Covalent immobilization of a glucoamylase to bagasse dialdehyde cellulose[J]. World Journal of Micobiology and Biotechnology,2001, 17(7):721-725.
    [22]Varavinit S, Chaokasem N, Shobsngob S. Immobilization of a thermostable alpha-amylase[J]. Science Asia,2002,28:247-251.
    [23]Wagner C N J. Direct methods for the determination of atomic-scale structure of amorphous solids (X-ray, electron, and neutron scattering)[J]. Journal of Non-Crystalline Solids,1978,31(1-2):1-40.

© 2004-2018 中国地质图书馆版权所有 京ICP备05064691号 京公网安备11010802017129号

地址:北京市海淀区学院路29号 邮编:100083

电话:办公室:(+86 10)66554848;文献借阅、咨询服务、科技查新:66554700