Experimental and Numerical Analysis of High-Resolution Injection Technique for Capillary Electrophoresis Microchip

Chin-Lung Chang,Ting-Fu Hong,Lung-Ming Fu,Jik-Chang Leong,Yao-Nan Wang

doi:10.3390/ijms12063594

Abstract

This study presents an experimental and numerical investigation on the use of high-resolution injection techniques to deliver sample plugs within a capillary electrophoresis (CE) microchip. The CE microfluidic device was integrated into a U-shaped injection system and an expansion chamber located at the inlet of the separation channel, which can miniize the sample leakage effect and deliver a high-quality sample plug into the separation channel so that the detection performance of the device is enhanced. The proposed 45° U-shaped injection system was investigated using a sample of Rhodamine B dye. Meanwhile, the analysis of the current CE microfluidic chip was studied by considering the separation of Hae III digested ϕx-174 DNA samples. The experimental and numerical results indicate that the included 45° U-shaped injector completely eliminates the sample leakage and an expansion separation channel with an expansion ratio of 2.5 delivers a sample plug with a perfect detection shape and highest concentration intensity, hence enabling an optimal injection and separation performance.

Highlights

In recent years, integrated microfluidic devices, known as “Lab-on-a-Chip”, have been utilized for the analysis of chemical or biological assays in biochemistry, biophysics, medicine and life sciences [1,2,3,4,5,6,7,8,9,10]
This study proposes a capillary electrophoresis (CE) microfluidic device with a novel injection structure with a 45°U-shaped injector and an expansion chamber at the inlet of the separation channel to improve the sample plug distribution in the separation step and enhance separation efficiency
This study performed the experimental separation of samples consisting of Rhodamine B fluorescent dye and Hae III digested φx-174 DNA samples to explore the effects of the 45°U-shaped injector and expansion chamber on the sample leakage and separation performance

Summary

Introduction

In recent years, integrated microfluidic devices, known as “Lab-on-a-Chip”, have been utilized for the analysis of chemical or biological assays in biochemistry, biophysics, medicine and life sciences [1,2,3,4,5,6,7,8,9,10]. Tsai et al [33,34,35] presented a microfluidic CE device incorporating a conventional cross-form injection system and an expansion chamber located at the inlet of the separation channel. To achieve high-performance detection in a CE microfluidic device, the sample leakage effect and shape of the sample plugs separated into the separation channel is of great importance. This study presents an integrated CE microfluidic device that combines a 45°U-shaped injection system with an expansion chamber at the inlet of the separation channel to eliminate the sample leakage effect and deliver high-quality sample bands into the separation channel. This study shows that the proposed low leakage injector improves the sample separation and the current expansion chamber advances the high-quality sample bands into the separation channel to enhance the detection performance

Chip Fabrication and Experimental Setup

Numerical Modeling

Results and Discussion

Conclusions