Surface charge, electroosmotic flow and DNA extension in chemically modified thermoplastic nanoslits and nanochannels.
Surface charge, electroosmotic flow and DNA extension in chemically modified thermoplastic nanoslits and nanochannels.
复制标题
DOI：
10.1039/c4an01439a
复制
发表时间：
2015-01-07
期刊：
影响因子：
--
通讯作者：
Soper SA
中科院分区：
文献类型：
--
作者：
Uba FI;Pullagurla SR;Sirasunthorn N;Wu J;Park S;Chantiwas R;Cho YK;Shin H;Soper SA
热塑性塑料已经成为玻璃/石英微流体的有吸引力的替代品，但是热塑性纳米流体器件的实现一直很慢，尽管可以用来生产这些器件的制造技术相当简单。这种缓慢的转变部分归因于对表面电荷对单分子通过热塑性纳米通道传输特性的影响的理解不足。我们报道了热塑性纳米通道的表面改性，并评估了相关的表面电荷密度、ζ电位和电渗透流（EOF）。采用聚甲基丙烯酸甲酯、PMMA制备了混合尺度流控网络。利用氧等离子体制备表面约束羧酸，并采用低温熔合组装器件。用乙二胺（EDA）通过EDC偶联实现羧化表面的胺化。XPS和ATR-FTIR显示在适当制备的表面上存在羧基和胺基。建立了一个修正的纳米通道电导方程来确定其表面电导，并发现与我们的实验结果很好地吻合。这些器件的表面电荷密度和zeta电位均低于玻璃纳米流体器件，并且取决于所采用的表面改性以及通道的大小。这种特性，再加上由于纳米限制导致的流体粘度的明显增加，使得PMMA纳米流体器件中的EOF比微尺度器件的EOF抑制了一个数量级。羧基化PMMA纳米通道对于λ-DNA的运输和延伸是有效的，而这些相同的DNA分子无法通过胺化纳米通道进行转运。
Thermoplastics have become attractive alternatives to glass/quartz for microfluidics, but the realization of thermoplastic nanofluidic devices has been slow in spite of the rather simple fabrication techniques that can be used to produce these devices. This slow transition has in part been attributed to insufficient understanding of surface charge effects on the transport properties of single molecules through thermoplastic nanochannels. We report the surface modification of thermoplastic nanochannels and an assessment of the associated surface charge density, zeta potential and electroosmotic flow (EOF). Mixed-scale fluidic networks were fabricated in poly(methylmethacrylate), PMMA. Oxygen plasma was used to generate surface-confined carboxylic acids with devices assembled using low temperature fusion bonding. Amination of the carboxylated surfaces using ethylenediamine (EDA) was accomplished via EDC coupling. XPS and ATR-FTIR revealed the presence of carboxyl and amine groups on the appropriately prepared surfaces. A modified conductance equation for nanochannels was developed to determine their surface conductance and was found to be in good agreement with our experimental results. The measured surface charge density and zeta potential of these devices were lower than glass nanofluidic devices and dependent on the surface modification adopted, as well as the size of the channel. This property, coupled to an apparent increase in fluid viscosity due to nanoconfinement, contributed to the suppression of the EOF in PMMA nanofluidic devices by an order of magnitude compared to the micro-scale devices. Carboxylated PMMA nanochannels were efficient for the transport and elongation of λ-DNA while these same DNA molecules were unable to translocate through aminated nanochannels.
登录
查看更多内容
影响因子：
3.9
作者：
Chai, JN;Lu, FZ;Kwok, DY
通讯作者：
Kwok, DY
影响因子：
46.2
作者：
Chantiwas R;Park S;Soper SA;Kim BC;Takayama S;Sunkara V;Hwang H;Cho YK
通讯作者：
Cho YK
影响因子：
8.6
作者：
Bakajin, OB;Duke, TAJ;Cox, EC
通讯作者：
Cox, EC
影响因子：
3.9
作者：
Chan-Park, MB;Yan, YH;Yue, CY
通讯作者：
Yue, CY
影响因子：
6.1
作者：
Chantiwas, Rattikan;Hupert, Mateusz L.;Soper, Steven A.
通讯作者：
Soper, Steven A.