Smearing Observation of Picoliter Droplets Pinning on Bio-Inspired Negative Lotus Leaf Replicas

摘要

Separating aqueous samples into large numbers of independent micro-droplets enables efficient study of single cells and detection of single molecules. However, as the droplet size becomes smaller, the reinforced handling process is possibly required to ensure droplets operability, resulting in increased experimental complexity. Herein, we propose a method of imitating the bio-structure of lotus leave reversal to generate a picoliter droplet array effectively. This bio-inspired structure is made of a single material PDMS (polydimethylsiloxane) without any additional chemical surface treatments. Only smearing is required for embedding liquid samples in such microwells with splayed walls. In the present experiments, we have obtained a regular array of 2 pL droplets with a density of 62,500 droplets/cm(2), which equivalents to 5.4 million droplets on the surface a 96 well plate. We believe that such a method contributes to the development of the efficient micro-droplet generator with a pure physical interface and thus it is applicable to biological and medical analysis.