Glass-based microchip with finger electrodes for the formation, collection, and biointeractions of liposomes

Abstract

A concept using a glass-based microchip with finger electrodes, under a two-step voltage-controlled manner, to accomplish the formation and collection of liposomes is presented. By the actions of electro-osmotic and electrolytic bubbles in low and high applied voltages, respectively, the liposomes were first formed in an electrolyte reservoir; then, they were successfully moved to a collected reservoir, which is helpful for subsequent on-chip processing. This study evaluated the distribution of an electric field for different couple-finger distances using finite-element analysis software. The simulation result shows that the electric field density increases rapidly with the decrease of finger distance, with a quadratic relationship. Experiment results show that, when the applied AC voltage is 1 Vp-p, at a driving frequency of 10 Hz, the liposomes are first formed near the boundary of the electrolyte reservoir, and when the voltage is higher, the mass production of liposomes is achieved. When the voltage is higher than 4 Vp-p, the electrolytic bubbles grow cyclically to separate the liposomes from the electrolyte reservoir and therefore collect in a specific reservoir. Liposomes encapsulate doxorubicin, and their drug release to the lung cancer cell line H1299 was also implemented to verify their biointeraction characteristics. These experimental results were all identified using an inverted fluorescence microscope.