title: Synthesis and fluorescence properties of N-substituted 1-cyanobenz[f]isoindole chitosan polymers and nanoparticles for live cell imaging.
abstract: Highly fluorescent N-substituted 1-cyanobenz[f]isoindole chitosans (CBI-CSs) with various degrees of N-substitution (DS) were synthesized by reacting chitosan (CS) with naphthalene-2,3-dicarboxaldehyde (NDA) in the presence of cyanide under mild acidic conditions. Introduction of 1-cyanobenz[f]isoindole moieties into the CS backbone resulted in lowering of polymer thermal stability and crystallinity. The fluorescence quantum yield (Φf) of CBI-CS was found to be DS- and molecular-weight-dependent, with Φf decreasing as DS and molecular weight were increased. At similar DS values, CBI-CS exhibited 26 times higher Φf in comparison with fluorescein isothiocyanate-substituted chitosan (FITC-CS). CBI-CS/TPP nanoparticles were fabricated using an ionotropic gelation method in which pentasodium triphosphate (TPP) acted as a cross-linking agent. CS and CBI-CS exhibited low cytotoxicity to normal skin fibroblast cells over a concentration range of 0.1-1000 μg/mL, while an increased cytotoxicity level was evident in CBI-CS/TPP nanoparticles at concentrations greater than 100 μg/mL. In contrast with CBI-CS polymers, the CBI-CS/TPP nanoparticles exhibited lower fluorescence; however, confocal microscopy results showed that living normal skin fibroblast cells became fluorescent on nanoparticle uptake. These results suggest that CBI-CS and fabricated nanoparticles thereof may be promising fluorescence probes for live cell imaging.
authors: National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency (NSTDA) , 111 Thailand Science Park, Phahonyothin Road, Pathum Thani 12120, Thailand.
authors: Pattarapond
authors: P
authors: Gonil
authors: Warayuth
authors: W
authors: Sajomsang
authors: Uracha Rungsardthong
authors: UR
authors: Ruktanonchai
authors: Preeyawis
authors: P
authors: Na Ubol
authors: Alongkot
authors: A
authors: Treetong
authors: Praneet
authors: P
authors: Opanasopit
authors: Satit
authors: S
authors: Puttipipatkhachorn
mesh_terms: D048271:Chitosan / Q000737:chemistry / Q000494:pharmacology; D005347:Fibroblasts / Q000166:cytology*; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D006801:Humans; D008856:Microscopy, Fluorescence / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*
chemical_list: D005456:Fluorescent Dyes; D048271:Chitosan