Edman C F, Raymond D E, Wu D J, Tu E, Sosnowski R G, Butler W F, Nerenberg M, Heller M J
Nanogen, 10398 Pacific Center Court, San Diego, CA 92121, USA.
Nucleic Acids Res. 1997 Dec 15;25(24):4907-14. doi: 10.1093/nar/25.24.4907.
Selection and adjustment of proper physical parameters enables rapid DNA transport, site selective concentration, and accelerated hybridization reactions to be carried out on active microelectronic arrays. These physical parameters include DC current, voltage, solution conductivity and buffer species. Generally, at any given current and voltage level, the transport or mobility of DNA is inversely proportional to electrolyte or buffer conductivity. However, only a subset of buffer species produce both rapid transport, site specific concentration and accelerated hybridization. These buffers include zwitterionic and low conductivity species such as: d- and l-histidine; 1- and 3-methylhistidines; carnosine; imidazole; pyridine; and collidine. In contrast, buffers such as glycine, beta-alanine and gamma-amino-butyric acid (GABA) produce rapid transport and site selective concentration but do not facilitate hybridization. Our results suggest that the ability of these buffers (histidine, etc.) to facilitate hybridization appears linked to their ability to provide electric field concentration of DNA; to buffer acidic conditions present at the anode; and in this process acquire a net positive charge which then shields or diminishes repulsion between the DNA strands, thus promoting hybridization.
选择和调整合适的物理参数能够在有源微电子阵列上实现快速的DNA传输、位点选择性富集以及加速杂交反应。这些物理参数包括直流电流、电压、溶液电导率和缓冲液种类。一般来说，在任何给定的电流和电压水平下，DNA的传输或迁移率与电解质或缓冲液的电导率成反比。然而，只有一部分缓冲液种类既能实现快速传输、位点特异性富集又能加速杂交。这些缓冲液包括两性离子和低电导率的物质，如：d-和l-组氨酸；1-和3-甲基组氨酸；肌肽；咪唑；吡啶；和可力丁。相比之下，诸如甘氨酸、β-丙氨酸和γ-氨基丁酸（GABA）等缓冲液能实现快速传输和位点选择性富集，但不能促进杂交。我们的结果表明，这些缓冲液（如组氨酸等）促进杂交的能力似乎与其提供DNA电场富集的能力、缓冲阳极处存在的酸性条件的能力有关；并且在此过程中获得净正电荷，进而屏蔽或减少DNA链之间的排斥力，从而促进杂交。
