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Selective parallel G-quadruplex recognition by a NIR-to-NIR two-photon squaraine

Fluorescence imaging probes for specific G-quadruplex (G4) conformations are of considerable interest in biomedical research. Herein, we present the synthesis and the binding properties of a new water-soluble near-infrared (NIR) amphiphilic squaraine dye (CAS-C1) which is capable of selective detect...

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Detalles Bibliográficos
Autores principales: Grande, Vincenzo, Shen, Chia-An, Deiana, Marco, Dudek, Marta, Olesiak-Banska, Joanna, Matczyszyn, Katarzyna, Würthner, Frank
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Royal Society of Chemistry 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6240894/
https://www.ncbi.nlm.nih.gov/pubmed/30542585
http://dx.doi.org/10.1039/c8sc02882f
Descripción
Sumario:Fluorescence imaging probes for specific G-quadruplex (G4) conformations are of considerable interest in biomedical research. Herein, we present the synthesis and the binding properties of a new water-soluble near-infrared (NIR) amphiphilic squaraine dye (CAS-C1) which is capable of selective detection of parallel over non-parallel and non G4 topologies. The striking changes in its linear optical response upon binding to parallel G4s give rise to high fluorescence quantum yields (Φ(f) ≈ 0.7) and one-photon molecular brightness in the far-red-NIR region. The outstanding recognition process of CAS-C1 for parallel G4s via end-stacking provides binding constants in the nanomolar regime (K(b) = 10(7) to 10(8) M(–1)) awarding it as one of the most potent parallel G4 binders currently available. Moreover, the CAS-C1-parallel G4 system exhibits large two-photon absorption (TPA) cross-sections and molecular brightness in the second NIR biological transparency window (λ ≈ 1275 nm), making it an ideal candidate for NIR-to-NIR ultrasensitive two-photon procedures.