PAMAM Structure‐Based Multifunctional Fluorescent Conjugates for Improved Fluorescent Labelling of Biomacromolecules

Abstract

Fluorescent probes are of increasing interest in medicinal and biological applications for the elucidation of the structures and functions of healthy as well as tumour cells. The quality of these investigations is determined by the intensity of the fluorescence signal. High dye/carrier ratios give strong signals. However, these are achieved by the occupation of a high number of derivatisation sites and therefore are accompanied by strong structural alterations of the carrier. Hence, polyvalent substances containing a high number of fluorescent dyes would be favourable because they would allow the introduction of many dyes at one position of the compound to be labelled.A large number of different dyes have been investigated to determine the efficiency of coupling to a dendrimer scaffold and the fluorescence properties of the oligomeric dyes, but compounds that fulfil the requirements of both strong fluorescence signals and reactivities are rare. Herein we describe the synthesis and characterisation of dye oligomers containing dansyl-, 7-nitro-2,1,3-benzoxadiazol-4-yl- (NBD), coumarin-343, 5(6)-carboxyfluorescein and sulforhodamine B2 moieties based on polyamidoamine (PAMAM) dendrimers. The PAMAM dendrimers were synthesised by an improved protocol that yielded highly homogeneous scaffolds with up to 128 conjugation sites. When comparing the fluorescent properties of the dye oligomers it was found that only the dansylated dendrimers met the requirements of enhanced fluorescence signals. The dendrimer containing 16 fluorescent dyes was conjugated to the anti-epidermal-growth-factor receptor (EGFR) antibody hMAb425 as a model compound to show the applicability of the dye multimer compounds. This conjugate revealed a preserved immunoreactivity of 54%.We demonstrate the applicability of the dye oligomers to the efficient and applicable labelling of proteins and other large molecules that enables high dye concentrations and therefore high contrasts in fluorescence applications.

Application of 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole in analysis: Fluorescent dyes and unexpected reaction with tertiary amines

“…NBD fragments are applied in the synthesis of fluorescent nanoparticles [23][24][25][26] as a tool of nanoparticles investigation and also for design of fluorescent nanoprobes, thermal sensors and optical devices.…”

Silica nanoparticle-based dual imaging colloidal hybrids: cancer cell imaging and biodistribution

“…[31][32][33][34][35][36][37][38][39][40] Timely multi-functional MR imaging contrast-enhancing nanoparticles have been studied in biomedical applications. [41][42][43][44][45][46][47][48][49][50][51][52] With the above in mind, we designed silica nanoparticles to have a dual imaging mode, ie, (MR) imaging and fluorescent optical imaging. Poly(ethylene glycol) (PEG) and PEG-containing block copolymers, with very flexible and hydrophilic properties, were conjugated onto the silica nanoparticles to enable them to escape uptake by the mononuclear phagocyte system.…”

Mono-, di-, and tri-nuclear gold(I) complexes with dansyl moiety: Synthesis, characterization, and photophysical properties

“…The lowestlying emissive excited states for metal complexes are dependent on the nature of metal centers and ligands. 5-Dimethylamino-naphthalene-1-sulfonyl (dansyl) group is one of the most important chromophores used in molecular sensing and labeling [5][6][7][8][9]. It exhibits intense absorption in the UV region and emits in the visible regime with high fluorescence quantum yield as well as high resistance to photo-bleaching.…”

“…It exhibits intense absorption in the UV region and emits in the visible regime with high fluorescence quantum yield as well as high resistance to photo-bleaching. In addition, its modification can be easily carried out by organic synthesis [7][8][9].We have a long-term interest in studying the lowest-lying emissive excited states of metal complexes with d 10 configuration [10][11][12][13]. In view of the isolobal concept [14], in which Ph 3 PAu + is isolobal to H + , we envisaged that if the proton (or protons) of dansylamide (5-dimethylamino-naphthalene-1-sulfonamide) can be replaced by Ph 3 PAu + , it would be interesting to study the luminescence properties of the "gilded" dansylamides.…”