Manipulation of massive droplets, particles, as well as cells has enabled wide applications. However, most existing technologies require complicated processes, operations, or external setup. This article demonstrates the employment of biomimetic Nepenthes peristome surfaces (NPS) in achieving ultrafast microdroplet generation and high-density microparticle arraying, with the assistance of curvature-induced Laplace pressure in slipping mode and evaporation-driven Marangoni effect in climbing mode, respectively. Different wetting phenomena on the biomimetic NPS were observed under variable contact angles and tilting angles, strongly affecting the microdroplet generation and microparticle array. As the optimal results, 5 μm-size microparticles were arrayed with 85% coverage rate in 65 s and 20 μm-size microdroplets were arrayed with 100% coverage rate in 3 s. In this study, this well-designed bionic surface shows excellent performances as an ultrafast, universal, and straightforward approach to capture and array micro-objects in aqueous solutions for various biological and chemical analyses.
Keywords: Marangoni flow; microdroplet; microparticle; nepenthes peristome; planar microfluidics.