High‐Throughput Continuous‐Flow Separation in a Micro Free‐Flow Electrophoresis Glass Chip Based on Laser Microfabrication

Abstract

Micro free‐flow electrophoresis (μFFE) provides a rapid and straightforward route for the high‐performance online separation and purification of targeted liquid samples in a mild manner. However, the facile fabrication of a μFFE device with high throughput and high stability remains a challenge due to the technical barriers of electrode integration and structural design for the removal of bubbles for conventional methods. To address this, the design and fabrication of a high‐through-put μFFE chip are proposed using laser‐assisted chemical etching of glass followed by electrode integration and subsequent low‐temperature bonding. The careful design of the height ratio of the separation chamber and electrode channels combined with a high flow rate of buffer solution allows the efficient removal of electrolysis‐generated bubbles along the deep electrode channels during continuous‐flow separation. The introduction of microchannel arrays further enhances the stability of on‐chip high‐throughput separation. As a proof‐of‐concept, high‐performance purification of flu-orescein sodium solution with a separation purity of ~97.9% at a voltage of 250 V from the mixture sample solution of fluorescein sodium and rhodamine 6G solution is demonstrated.