Wirth M J, Fairbank R W, Fatunmbi H O
Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
Science. 1997 Jan 3;275(5296):44-7. doi: 10.1126/science.275.5296.44.
Chemical separations of many biomolecules and pharmaceuticals are limited by their electrostatic interaction with the surfaces of the separation medium. Mixed self-assembled monolayers of octadecyl and methyl chains organize into a dense, two-dimensionally cross-linked network over the chromatographic silica surface to reduce acid dissociation of the surface silanols. Molecular models predict that two-dimensional cross-linking is sterically possible for pure methylsiloxane monolayers, silicon-29 nuclear magnetic resonance measurements show that cross-linking predominates for mixed monolayers of primarily methylsiloxane, and chromatographic measurements confirm that electrostatic interactions are reduced when the monolayer is primarily methylsiloxane. Chromatographic separation of genetic variants of a highly charged protein, cytochrome c, demonstrates the promise of self-assembled monolayers in separations of biomolecules.
许多生物分子和药物的化学分离受到它们与分离介质表面静电相互作用的限制。十八烷基和甲基链的混合自组装单分子层在色谱硅胶表面形成致密的二维交联网络，以减少表面硅醇的酸解离。分子模型预测，纯甲基硅氧烷单分子层在空间上可能实现二维交联，硅-29核磁共振测量表明，主要为甲基硅氧烷的混合单分子层中交联占主导地位，色谱测量证实，当单分子层主要为甲基硅氧烷时，静电相互作用会减弱。对高电荷蛋白质细胞色素c的遗传变体进行色谱分离，证明了自组装单分子层在生物分子分离中的应用前景。
