A digital microfluidic platform based on a near-infrared light-responsive shape-memory micropillar array

• Published in: Lab on a chip 2021-03, Vol.21 (6), p.1131-1138
• Main Authors: Ye, Wen-Qi, Wei, Yun-Yun, Wang, Dan-Ni, Yang, Chun-Guang, Xu, Zhang-Run
• Format: Article
• Language: English
• Subjects: Analytical chemistry; Ascorbic acid; Copolymers; Droplets; Ethylene vinyl acetates; Infrared lasers; Infrared radiation; Laser arrays; Laser beam heating; Light; Light irradiation; Microfluidics; Shape memory; Technology assessment
• ISSN: 1473-0197; 1473-0189
• DOI: 10.1039/d0lc01324b

In this work, we developed a digital microfluidic platform based on a shape memory micropillar array responsive to near-infrared light, and the droplets were programmatically manipulated through light-induced micropillar deformation. The micropillar array was constructed on the surface of a poly(ethylene-vinyl acetate) copolymer, a shape memory polymer sensitive to near-infrared light. Before droplet manipulation, the micropillar array was kept temporarily tilted by heating and pressing. Under the irradiation of a near-infrared laser, the micropillar array achieved the transition from the temporary shape to the original shape. Temperature gradient and micropillar deformation caused by near-infrared light irradiation produce the driving force for droplet movement. The movement of the laser mounted on an electronically controlled displacement platform was controlled by a computer to achieve the programmed control of the droplets. Moreover, we demonstrated light-manipulated droplet movement and fusion, and achieved ascorbic acid detection using this digital microfluidic platform. In particular, the micropillar array chip is able to manipulate droplets in a wide range of 0.1 μL to 10 μL. The proposed digital microfluidic platform will broaden the application of digital microfluidic technology in analytical chemistry and biomedicine. Droplet manipulation on a near-infrared light-responsive shape-memory micropillar array.