Fast advancements of microfabrication processes in past two decades have reached to a fairly matured stage that we can manufacture a wide range of microfluidic devices. At present, the main challenge is the control of nanoscale properties on the surface of lab-on-a-chip to satisfy the need for biomedical applications. For example, poly(dimethylsiloxane) (PDMS) is a commonly used material for microfluidic circuitry, yet the hydrophobic nature of PDMS surface suffers serious nonspecific protein adsorption. Thus the current major efforts are focused on surface molecular property treatments for satisfying specific needs in handling macro functional molecules. Reviewing surface modifications of all types of materials used in microfluidics will be too broad. This review will only summarize recent advances in nonbiofouling PDMS surface modification strategies applicable to microfluidic technology and classify them into two main categories: (1) physical approach including physisorption of charged or amphiphilic polymers and copolymers, as well as (2) chemical approach including self assembled monolayer and thick polymer coating. Pros and cons of a collection of available yet fully exploited surface modification methods are briefly compared among subcategories.

中文翻译：

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基于聚二甲基硅氧烷 (PDMS) 的微流体装置的表面分子特性改性。

过去二十年微制造工艺的快速发展已经达到了一个相当成熟的阶段，我们可以制造各种微流体设备。目前，主要挑战是控制芯片实验室表面的纳米级特性以满足生物医学应用的需求。例如，聚二甲基硅氧烷 (PDMS) 是一种常用的微流体电路材料，但 PDMS 表面的疏水性会受到严重的非特异性蛋白质吸附。因此，当前的主要努力集中在表面分子特性处理上，以满足处理大功能分子的特定需求。审查微流体中使用的所有类型材料的表面改性将过于宽泛。本综述将仅总结适用于微流体技术的非生物污染 PDMS 表面改性策略的最新进展，并将其分为两大类：（1）物理方法，包括带电或两亲性聚合物和共聚物的物理吸附，以及（2）化学方法，包括自组装的单层和厚聚合物涂层。在子类别之间简要比较了一系列可用但已充分利用的表面改性方法的优缺点。