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C. Lamprecht, B. Plochberger, V. Ruprecht, S. Wieser, C. Rankl, E. Heister, B. Unterauer, M. Brameshuber, J. Danzberger, P. Lukanov, E. Flahaut, G. Schütz, P. Hinterdorfer, A. Ebner:
"A single-molecule approach to explore binding, uptake and transport of cancer cell targeting nanotubes";
Nanotechnology, 25 (2014), 1257041 - 1257049.

In the past decade carbon nanotubes (CNTs) have been widely studied as a potential
drugdelivery
system, especially with functionality for cellular targeting. Yet, little is known
about the actual process of docking to cell receptors and transport dynamics after
internalization. Here we performed singleparticle
studies of folic acid (FA) mediated CNT
binding to human carcinoma cells and their transport inside the cytosol. In particular, we
employed molecular recognition force spectroscopy, an atomic force microscopy based
method, to visualize and quantify docking of FA functionalized CNTs to FA binding receptors
in terms of binding probability and binding force. We then traced individual fluorescently
labeled, FA functionalized CNTs after specific uptake, and created a dynamic `roadmap´ that
clearly showed trajectories of directed diffusion and areas of nanotube confinement in the
cytosol. Our results demonstrate the potential of a singlemolecule
approach for investigation
of drugdelivery
vehicles and their targeting capacity.

AFM, molecular recognition, force spectroscopy, carbon nanotubes, particle tracking