Capillary electrophoresis electrochemical (CE-EC) detection on a novel thread-based microfluidic device with 3D sensing electrodes

Abstract

Capillary electrophoresis (CE) has been used in a number of bio-analytical detection in the past decays [1]. This detection scheme has high separation efficiency and rapid detection capability. Fluorescence detection is the most common adopted method in capillary electrophoresis system. However, fluorescence detection approach relies on fluorescence labeling and delicate optical excitation and detection components. Alternatively, electrochemical detection can rapid detect the electrical changes caused by the passing samples [2]. The combination of capillary electrophoresis separation and electrochemical detection (CEEC) has been used in a variety of application. CEEC detection was usually carried out using the amperometric detection method. However, typical CE chips are with closed-channel design which needs a number of microfabrication process including micro-channel forming and chip bonding to form the sealed microfluidic channel. Therefore, the fabrication process for producing typical CE chip is comparable time-consuming and expensive. Consequently, to use polymers as substrates for microchip fabrication is faster and cheaper way than glass device and can be fabricated without accessing the clean-room facilities [3, 4]. One major problem for using the microfluidic chips with physical channels is that these chips may suffer from pollutions or clogging while repeating using these chips. Due to the difficulty for cleaning sealed microfluidic channels. Disposing the chip can simple solve this problem but the cost is another issue. Therefore, it is beneficial to develop microfluidic systems without using physical sealed channels, or so-called non-channel based microfluidic systems.