Mucus membranes, such as those in the intestine, nose, eyes, vagina andmouth, are good targets for therapeutic drug delivery thanks to theirlarge surface area and rich blood supply. But these membranes, whichcan be several hundreds of microns thick, are important barriers todrug penetration. Previous delivery devices focused on microscalestructures that were chemically modified with molecules like lectins sothat they would better adhere to mucus cells. Yet the problem here isthat such devices are eliminated in a matter of hours as the mucusnaturally turns over.
Now, a team led by Tejal Desai and Kayte Fischer of theUniversity of California at San Francisco, has shown that siliconnanowires can penetrate the mucus layer and adhere to the underlyingepithelium. This means that the nanowires remain on the cells for up tothree days (the cell turnover time). "Our result supports the notionthat decreasing the size of surface structures increases adhesion - whether through van der Waals adhesion or other nanoscale interactionswith cells," said Desai.
Source: nanotechweb.orgAdded: 25 February 2009