Our work focuses on the development of simpler and effective production of nanofluidic devices for high-throughput charged single nanoparticle trapping in an aqueous environment. Single nanoparticle confinement using electrostatic trapping has been an effective approach to study the fundamental properties of charged molecules under a controlled aqueous environment. Conventionally, geometry-induced electrostatic trapping devices are fabricated using SiOx-based substrates and comprise nanochannels imbedded with nanoindentations such as nanopockets, nanoslits and nanogrids. These geometry-induced electrostatic trapping devices can only trap negatively charged particles, and therefore, to trap positively charged particles, modification of the device surface is required. However, the surface modification process of a nanofluidic device is cumbersome and time consuming. Therefore, here, we present a novel approach for the development of surface-modified geometry-induced electrostatic trapping devices that reduces the surface modification time from nearly 5 days to just a few hours. We utilized polydimethylsiloxane for the development of a surface-modified geometry-induced electrostatic trapping device. To demonstrate the device efficiency and success of the surface modification procedure, a comparison study between a PDMS-based geometry-induced electrostatic trapping device and the surface-modified polydimethylsiloxane-based device was performed. The device surface was modified with two layers of polyelectrolytes (1: poly(ethyleneimine) and 2: poly(styrenesulfonate)), which led to an overall negatively charged surface. Our experiments revealed the presence of a homogeneous surface charge density inside the fluidic devices and equivalent trapping strengths for the surface-modified and native polydimethylsiloxane-based geometry-induced electrostatic trapping devices. This work paves the way towards broader use of geometry-induced electrostatic trapping devices in the fields of biosensing, disease diagnosis, molecular analysis, fluid quality control and pathogen detection.

我们的工作重点是开发更简单有效的纳米流体装置，用于在水性环境中捕获高通量带电单纳米粒子。使用静电捕获的单个纳米粒子限制已成为研究受控水环境下带电分子基本性质的有效方法。通常，几何诱导静电捕获装置是使用基于 SiOx 的衬底制造的，并且包括嵌入纳米压痕的纳米通道，例如纳米袋、纳米狭缝和纳米网格。这些几何诱导的静电捕获装置只能捕获带负电的粒子，因此，要捕获带正电的粒子，需要修改装置表面。然而，纳米流体装置的表面改性过程既繁琐又耗时。因此，在这里，我们提出了一种开发表面改性几何诱导静电捕获装置的新方法，该方法将表面改性时间从近 5 天减少到几个小时。我们利用聚二甲基硅氧烷开发了一种表面改性几何诱导静电捕获装置。为了证明表面改性程序的设备效率和成功，进行了基于 PDMS 几何诱导静电捕获设备和表面改性聚二甲基硅氧烷设备之间的比较研究。器件表面用两层聚电解质（1：聚（乙烯亚胺）和 2：聚（苯乙烯磺酸盐））改性，这导致整体表面带负电。我们的实验表明，流体装置内部存在均匀的表面电荷密度，并且表面改性和基于天然聚二甲基硅氧烷的几何诱导静电捕获装置具有等效的捕获强度。这项工作为在生物传感、疾病诊断、分子分析、流体质量控制和病原体检测领域更广泛地使用几何诱导静电捕获装置铺平了道路。