ABSTRACT
A great number of studies focus their interest on the photophysical properties of fluorescent hybrid gold nanoparticles for potential applications in biotechnologies such as imaging and/or treatment. Spherical gold nanoparticles are known to quench a chromophore fluorescent signal, when moieties are located in their close vicinity. The use of a polymer spacer on such a system allowed only partial recovery of the dye emission by controlling the surface to dye distance. Gold-based anisotropic sharp nanostructures appear to exhibit more interesting features due to the strong electric field generated at their edges and tips. In this paper, a complete study of hybrid fluorescent bipyramidal-like gold nanostructures is presented. We describe the chemical synthesis of gold bipyramids functionalized with fluorescent water-soluble polymers and their photophysics both in solution and on a single object. We show that the use of a bipyramidal shape instead of a spherical one leads to total recovery of the fluorescence and even to an enhancement of the emission of the dyes by a factor of 1.4.
ABSTRACT
The living cationic polymerization of a saccharidic monomer (1,2:3,4-di-O-isopropylidene-6-O-(2-vinyloxyethyl)-D-galactopyranose, GVE) gives rise to aldehyde end-capped polymers (PGVE--CHO) of low molar masses (<10 000 Da) and low molar mass distribution (<1.2). These polymers were derivatized by selective introduction of either hexamethylenediamine (PGVE-NH2) or 9-fluorenylmethyl carbazate (PGVE-Fmoc) end groups. The resulting polymers were fully characterized by complementary use of nuclear magnetic resonance (1H NMR) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS). The expected structure according to the polymerization mechanism, the occurrence of side reactions and the success of the post-functionalization reactions were confirmed.
