Pre- and Postfunctionalized Self-Assembled π-Conjugated Fluorescent Organic Nanoparticles for Dual Targeting

Abstract

There is currently a high demand for novel approaches to engineer fluorescent nanoparticles with precise surface properties suitable for various applications, including imaging and sensing. To this end, we report a facile and highly reproducible one-step method for generating functionalized fluorescent organic nanoparticles via self-assembly of prefunctionalized π-conjugated oligomers. The engineered design of the nonionic amphiphilic oligomers enables the introduction of different ligands at the extremities of inert ethylene glycol side chains without interfering with the self-assembly process. The intrinsic fluorescence of the nanoparticles permits the measurement of their surface properties and binding to dye-labeled target molecules via Förster resonance energy transfer (FRET). Co-assembly of differently functionalized oligomers is also demonstrated, which enables the tuning of ligand composition and density. Furthermore, nanoparticle prefunctionalization has been combined with subsequent postmodification of azide-bearing oligomers via click chemistry. This allows for expanding ligand diversity at two independent stages in the nanoparticle fabrication process. The practicability of the different methods entails greater control over surface functionality. Through labeling with different ligands, selective binding of proteins, bacteria, and functionalized beads to the nanoparticles has been achieved. This, in combination with the absence of unspecific adsorption, clearly demonstrates the broad potential of these nanoparticles for selective targeting and sequestration. Therefore, controlled bifunctionalization of fluorescent π-conjugated oligomer nanoparticles represents a novel approach with high applicability to multitargeted imaging and sensing in biology and medicine.

Recent advances of semiconducting polymer nanoparticles in in vivo molecular imaging

“…The preparation methods, optical properties and bioconjugation chemistry of SPNs have been widely studied,[32, 34–36] and their biological applications have been demonstrated for in vitro sensing,[37–40] bioorthogonal labeling,[41] specific cellular and subcellular imaging,[29, 42–44] drug and gene delivery,[45, 46] and antimicrobial,[47, 48] as examined in a number of recent reviews. [21, 27, 28, 30, 31, 33, 49–53] This short review article will instead focus on recent advances of SPNs as molecular imaging probes in living animals.…”

Soft fluorescent nanomaterials for biological and biomedical imaging

“…In order to avoid the common ACQ effect, AIE-typed 107, 108 fluorophores were used to ensure strong fluorescence for biological imaging. 104, 105 Even without a surfactant, certain hydrophilic dyes with special structure can self-assemble into stable NPs. One example is a perylene diimide derivative.…”

Stark fluoreszierende halbleitende Polymerpunkte für Biologie und Medizin

“…[124][125][126] Konjugierte Polyelektrolyte mit hyperverzweigten Strukturen kçnnen so synthetisiert werden, dass sie in Wasser lçslich sind. [127][128][129] Amphiphile konjugierte Polymere und Oligomere kçnnen sich auch selbst zu sphäri-schen Partikeln oder Micellstrukturen ausordnen, die abstimmbare optische Eigenschaften zeigen [89][90][91] und als Bildgebungssonden und Transportvektoren dienen. [92,93] Darüber hinaus kçnnen herkçmmliche lineare konjugierte Polyelektrolyte oder hydrophile halbleitende Polymere, die stark mit hydrophilen Gruppen funktionalisiert sind, in Gegenwart von Salzen, Säuren oder entgegengesetzt geladenen Spezies ebenfalls in Nanopartikel umgewandelt werden.…”