FIGURE 12.

Schematic of the cascaded FRET QD-dendrimer nanotubes. A) Self-assembled porous alumina membrane is used as a template. B) The pore walls are coated with 3-aminopropyl-dimethylethoxysilane to provide a positive surface charge. C) 3-bilayers of dendrimer polyelectrolytes are then deposited, starting with the negatively charged species. D) Negatively charged QDs are then deposited inside the template starting with QD⁵⁶¹ (with luminescence maximum at k = 561 nm, i.e green), then QD⁵⁹⁴ (orange) and finally QD⁶¹⁴ (red). Five QD/positively charged dendrimer bilayers were deposited for each QD species. E) After activation by N-hydroxysuccinimide (NHS) / 1-ethyl-3-(dimethylamino)propylcarbodiimide (EDC), probe DNA (pDNA) immobilization and hybridization with Cy5-labeled complementary DNA (tDNA) can be achieved inside the NTs. Reproduced and adapted with permission from Feng et al. Adv. Mater. 2007, 19, 1933. Copyright 2007 Wiley-VCH Verlag GmbH & Co. KGaA.