The nanoscale architecture of force-bearing focal adhesions.

TitleThe nanoscale architecture of force-bearing focal adhesions.
Publication TypeJournal Article
Year of Publication2014
Authorsvan Hoorn, H., Harkes R., Spiesz E.M., Storm C., van Noort D., Ladoux B., Schmidt T.
JournalNano Lett
Volume14
Pagination4257-62
Date Published2014 Aug 13
ISSN1530-6992
Abstract

The combination of micropillar array technology to measure cellular traction forces with super-resolution imaging allowed us to obtain cellular traction force maps and simultaneously zoom in on individual focal adhesions with single-molecule accuracy. We achieved a force detection precision of 500 pN simultaneously with a mean single-molecule localization precision of 30 nm. Key to the achievement was a two-step etching process that provided an integrated spacer next to the micropillar array that permitted stable and reproducible observation of cells on micropillars within the short working distance of a high-magnification, high numerical aperture objective. In turn, we used the technology to characterize the super-resolved structure of focal adhesions during force exertion. Live-cell imaging on MCF-7 cells demonstrated the applicability of the inverted configuration of the micropillar arrays to dynamics measurements. Forces emanated from a molecular base that was localized on top of the micropillars. What appeared as a single adhesion in conventional microscopy were in fact multiple elongated adhesions emanating from only a small fraction of the adhesion on the micropillar surface. Focal adhesions were elongated in the direction of local cellular force exertion with structural features of 100-280 nm in 3T3 Fibroblasts and MCF-7 cells. The combined measure of nanoscale architecture and force exerted shows a high level of stress accumulation at a single site of adhesion.

DOI10.1021/nl5008773
Alternate JournalNano Lett.
PubMed ID24998447
05/03/2015