Using “Protruding Nanoballs” and “Recessional Nanosuckers” in the same title is not something easily achievable. Luckily someone managed to do it: http://pubs.acs.org/doi/abs/10.1021/nl4048042
In the paper some more amazing NanoThings:
“shrunken nanoball architectures”
“…produced a great amount of suction when applied to other surfaces, similar to the effect of suckers on an octopus’ tentacles”
“The overall structure changed from a nanosphere to a “nanosnowman”-like structure with a smaller ball affixed atop the larger one.”
“The nanocup structure had a relatively small opening mouth on top of a spherical cavity”
“No matter the length of immersion in acetonitrile or the size of the nanoballs, those nanoballs displayed homogeneity in size and the same period of sequence; that is, smaller nanoballs had larger spaces between them.”
“…the nanosucker design presented in this article is the only octopus- inspired design”
P.S. The research described in the paper is extremely interesting, and achieving such strong adhesion with dry film is quite impressive. Check the videos in the supplementary information for the stress test (and a brutal vertical video).