A pneumatic open-surface microfluidic platform for droplet manipulation

This study presents a simple droplet-based manipulation method on an open-surface microfluidic platform. By using pneumatic suction force to cause a deflection of the flexible polydimethylsiloxane (PDMS)-based superhydrophobic membrane, the droplet on the membrane can be thereby activated. A facile one-step laser micromachining technique is used to fabricate superhydrophobic surface, a contact angle of 145° and hysteresis of 1.6° are achieved without any chemical modification. Relative to previously open-surface microfluidic system, this proposed platform is capable of simultaneous and precise delivery of droplets in 2-dimensional (2D) manipulation. Furthermore, droplets can be manipulated using a suction force, avoiding interference from a driving energy (e.g. heat, light, electricity). According to this approach, the proposed platform is suitable for the biological and chemical applications.