Pattarapond GonilWarayuth SajomsangUracha Rungsardthong RuktanonchaiPreeyawis Na UbolAlongkot TreetongPraneet OpanasopitSatit PuttipipatkhachornThailand National Science and Technology Development AgencySilpakorn UniversityMahidol University2018-11-092018-11-092014-08-11Biomacromolecules. Vol.15, No.8 (2014), 2879-288815264602152577972-s2.0-84905822755https://repository.li.mahidol.ac.th/handle/20.500.14594/33561Highly 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 f decreasing as DS and molecular weight were increased. At similar DS values, CBI-CS exhibited 26 times higherf 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 0.1-1000μg/mL, while an increased cytotoxicity level was evident in CBI-CS/TPP nanoparticles at concentrations greater than 100μg/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. © 2014 American Chemical Society.Mahidol UniversityChemical EngineeringMaterials ScienceMedicineArticleSCOPUS10.1021/bm5004459