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广东快乐十分稳赢大双:Physical immobilization of particles inspired by pollination
广东快乐十分投注下载 www.hmclip.net Edited by David Quéré, Ecole Supérieure de Physique et de Chimie Industrielles, Paris, France, and accepted by Editorial Board Member Pablo G. Debenedetti January 25, 2019 (received for review August 2, 2018)
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Honey bees present a peculiar hairy structure that covers the surface of their body, which is able to transport large quantities of pollen particles for pollination purposes. Inspired by this natural phenomenon and to overcome the current problems associated with drug patches with passive delivery, we propose the concept of a micropatterned surface featuring micropillars with defined spacing and height to mimic the hair of bees for the entrapment of a large quantity of microparticles. We believe that such substrates could be extended to diverse applications that require reversible immobilization of solid particulate objects. In particular, high drug content is required for obtaining more effective drug patches, enabling more sustained and targeted release of the drug.
Biomimetic systems often exhibit striking designs well adapted to specific functions that have been inspiring the development of new technologies. Herein, we explored the remarkable ability of honey bees to catch and release large quantities of pollen grains. Hair spacing and height on bees are crucial for their ability to mechanically fix pollen grains. Inspired by this, we proposed the concept of a micropatterned surface for microparticle entrapment, featuring high-aspect-ratio elastic micropillars spaced to mimic the hairy surface of bees. The hypothesis was validated by investigating the ability of polydimethylsiloxane microfabricated patches to fix microparticles. The geometrical arrangement, spacing, height, and flexibility of the fabricated micropillars, and the diameter of the microparticles, were investigated. Higher entrapment capability was found through the match between particle size and pillar spacing, being consistent with the observations that the diameter of pollen grains is similar to the spacing between hairs on bees’ legs. Taller pillars permitted immobilization of higher quantities of particles, consistent with the high aspect ratio of bees’ hairs. Our biomimetic surfaces were explored for their ability to fix solid microparticles for drug-release applications, using tetracycline hydrochloride as a model antibiotic. These surfaces allowed fixation of more than 20 mg/cm2 of antibiotic, about five times higher dose than commercialized patches (5.1 mg/cm2). Such bioinspired hairy surfaces could find applications in a variety of fields where dry fixation of high quantities of micrometer-sized objects are needed, including biomedicine, agriculture, biotechnology/chemical industry, and cleaning utensils.
?1L.F.S. and A.S.S. contributed equally to this work.
- ?2To whom correspondence should be addressed. Email: .
Author contributions: L.F.S., A.S.S., and J.F.M. designed research; L.F.S. and A.S.S. performed research; C.R.C. contributed new reagents/analytic tools; and L.F.S., A.S.S., C.R.C., and J.F.M. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission. D.Q. is a guest editor invited by the Editorial Board.
This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10.1073/pnas.1813336116/-/DCSupplemental.
Published under the PNAS license.