Lincopan Nilton, Carmona-Ribeiro Ana Maria
Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo,Caixa Postal 26077, São Paulo-SF, Brazil.
J Nanosci Nanotechnol. 2009 Jun;9(6):3578-86. doi: 10.1166/jnn.2009.ns33.
Cationic supported bilayers on latex are useful to isolate and immobilize oppositely charged proteins as a monomolecular layer over a range of low protein concentrations and particle number densities. Cholera toxin (CT) from Vibrio cholerae, an 87 kDa AB5 hexameric protein and bovine serum albumin (BSA) self-assembled on dioctadecyldimethylammonium bromide (DODAB) supported bilayers with high affinity yielding highly organized and monodisperse particulates at 5 x 10(9) particles/mL, over a range of low protein concentrations (0-0.025 mg/mL BSA or CT). Protein association onto the bilayer-covered polystyrene sulfate (PSS) was determined from adsorption isotherms, dynamic light scattering for size distributions and zeta-potential analysis revealing a monomolecular, thin and highly organized protein layer surrounding each particle with potential for biospecific recognition such as antigen-antibody, receptor-ligand, hybridization of oligonucleotide sequences, all of them important in immunodiagnosis, selective biomolecular chromatographic separations, microarrays design and others.
乳胶上的阳离子支撑双层对于在一系列低蛋白质浓度和颗粒数密度下，将带相反电荷的蛋白质作为单分子层分离和固定是有用的。来自霍乱弧菌的霍乱毒素（CT），一种87 kDa的AB5六聚体蛋白，以及牛血清白蛋白（BSA），在二辛基二甲基溴化铵（DODAB）支撑双层上以高亲和力自组装，在5×10⁹颗粒/毫升的浓度下，在一系列低蛋白质浓度（0 - 0.025毫克/毫升BSA或CT）范围内产生高度有序且单分散的颗粒。通过吸附等温线、动态光散射分析尺寸分布以及ζ电位分析来确定蛋白质与双层覆盖的聚苯乙烯磺酸盐（PSS）的结合情况，结果显示每个颗粒周围形成了单分子、薄且高度有序的蛋白质层，具有生物特异性识别的潜力，如抗原 - 抗体、受体 - 配体、寡核苷酸序列杂交等，所有这些在免疫诊断、选择性生物分子色谱分离、微阵列设计等方面都很重要。
