Dang Fuquan, Kakehi Kazuaki, Cheng Jingjun, Tabata Osamu, Kurokawa Masaya, Nakajima Kazuki, Ishikawa Mitsuru, Baba Yoshinobu
Nano-bioanalysis Team, Health Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Hayashi-cho 2217-14, Takamatsu 761-0395, Japan.
Anal Chem. 2006 Mar 1;78(5):1452-8. doi: 10.1021/ac051702f.
Hybrid dynamic coating using n-dodecyl beta-d-maltoside (DDM) and methyl cellulose (MC) has been developed for suppression of analyte adsorption and electroosmotic flow (EOF) in a poly(methyl methacrylate) (PMMA) channel. The adsorption of APTS-labeled sugars in a PMMA channel was obviously suppressed with DDM dynamic coating; however, EOF was reduced only by a factor of approximately 25%, resulting in irreproducible separations. In contrast, both analyte adsorption and EOF in a PMMA channel were efficiently minimized with MC coating; however, concentrated MC above 0.3% was required to achieve high-performance separations, which greatly increased viscosity of the solution and caused difficulties during buffer loading and rinsing. In addition, n-dodecyltrimethylammonium chloride did not show observable effects on reducing analyte adsorption, although it has the same hydrophobic alkyl chain as DDM. These results strongly indicated that the polysaccharide moiety of surface modifiers has a specific affinity to surface charges and is crucial to achieving efficient and stable dynamic coating on the PMMA surface. Hybrid dynamic coating with 0.25% DDM and 0.03% MC was found to minimize both analyte adsorption and EOF in a PMMA channel to a negligible level, while still keeping a low viscosity of the solution. High-speed and high-throughput profiling of the N-linked glycans derived from alpha1-acid glycoprotein, fetuin, and ribonuclease B was demonstrated in both single-channel and 10-channel PMMA chips using DDM-MC hybrid coating. We propose that DDM-MC hybrid coating might be a general method for suppressing analyte adsorption and EOF in polymer MCE devices. The current MCE-based method might be a promising alternative for high-throughput screening of carbohydrate alterations in glycoproteins.
已开发出使用正十二烷基-β-D-麦芽糖苷（DDM）和甲基纤维素（MC）的混合动态涂层，用于抑制聚甲基丙烯酸甲酯（PMMA）通道中分析物的吸附和电渗流（EOF）。在PMMA通道中，DDM动态涂层明显抑制了APTS标记糖的吸附；然而，EOF仅降低了约25%，导致分离结果不可重现。相比之下，MC涂层可有效最小化PMMA通道中的分析物吸附和EOF；然而，需要高于0.3%的浓缩MC才能实现高效分离，这大大增加了溶液的粘度，并在缓冲液加载和冲洗过程中造成困难。此外，尽管十二烷基三甲基氯化铵与DDM具有相同的疏水烷基链，但在减少分析物吸附方面未显示出明显效果。这些结果有力地表明，表面改性剂的多糖部分对表面电荷具有特定亲和力，对于在PMMA表面实现高效稳定的动态涂层至关重要。发现0.25% DDM和0.03% MC的混合动态涂层可将PMMA通道中的分析物吸附和EOF都最小化到可忽略的水平，同时仍保持溶液的低粘度。使用DDM-MC混合涂层在单通道和10通道PMMA芯片中展示了源自α1-酸性糖蛋白、胎球蛋白和核糖核酸酶B的N-连接聚糖的高速高通量分析。我们提出，DDM-MC混合涂层可能是抑制聚合物微流控芯片电泳（MCE）装置中分析物吸附和EOF的通用方法。当前基于MCE的方法可能是用于糖蛋白中碳水化合物变化高通量筛选的有前途的替代方法。
