https://phys.org/news/2018-07-soundwave-surfing-droplets.html

Automated fluid handling has driven the development of many scientific fields. Robotic pipetting systems have, for example, revolutionized the preparation of sequencing libraries, clinical diagnostics and large-scale compound screening. While ubiquitous in the modern biomedical research and pharmaceutical industries, these systems are bulky, expensive and do not handle small volumes of liquids well.

Lab-on-a-chip systems have been able to fill this space to some extent, but most are hindered by one major drawback—surface absorption. Because these devices rely on solid surfaces, the samples being transported inevitably leave traces of themselves that can lead to contamination.