Microscopy and optical manipulation of dendrimer-built vesicles

Gensch, T.; Tsuda, K.; Dol, G. C.; Latterini, L.; Weener, J. W.; Schenning, A. P. H. J.; Hofkens, J.; Meijer, E. W.; De Schryver, F. C.

doi:10.1351/pac200173030435

Pure Appl. Chem., 2001, Vol. 73, No. 3, pp. 435-441

http://dx.doi.org/10.1351/pac200173030435

Microscopy and optical manipulation of dendrimer-built vesicles

T. Gensch¹*, K. Tsuda¹, G. C. Dol¹, L. Latterini¹, J. W. Weener², A. P. H. J. Schenning², J. Hofkens¹, E. W. Meijer² and F. C. De Schryver¹

¹ Department of Chemistry, Katholieke Universiteit Leuven, Celestijnenlaan 200F, 3001 Heverlee, Belgium
² Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands

Abstract: A fifth-generation poly(propylene imine) dendrimer decorated with palmitoyl- and azobenzene-containing alkyl groups forms giant vesicles in aqueous solutions with diameters from 50 nm up to 20 mm and a multilaminar onion-like structure. Dense and ordered arrangement of the azobenzene chromophores in the bilayer structure leads to fluorescence with lmax= 600 nm. The fluorescence intensity can be increased by irradiation with blue light, and at low pH a distinctive blue shift of the spectrum is observed. With the aid of a single-beam optical tweezers it is possible to trap vesicles and direct them in a billiard-like fashion against each other using forces in the range of several pN. In collision experiments, the vesicles behave like hard spheres, and merging is not observed.