title: Singlet oxygen imaging in polymeric nanofibers by delayed fluorescence.
abstract: Polymeric nanofiber materials loaded with photosensitizers exhibit significant antibacterial activity due to their generation of cytotoxic singlet oxygen O(2)((1)Δ(g)). A time-gated fluorescence imaging technique was used to monitor the photosensitized processes in polystyrene (PS) and gelatin (GE) nanofibers loaded with 0.1 wt % tetraphenylporphyrin (TPP) photosensitizer. The fluorescence decay of TPP at the periphery of the PS nanofibers was single exponential. Increased fluorescence quenching was observed in the domains with higher TPP loading, located in the center of the nanofibers, and added a shorter lifetime component to the kinetics. The domains exhibiting singlet oxygen activity within the nanofibers were visualized and analyzed by singlet oxygen-sensitized delayed fluorescence imaging (SODF). Whereas O(2)((1)Δ(g)) was produced in PS nanofibers, its production in GE nanofibers was limited. These results were confirmed by time-resolved phosphorescence measurements at 1270 nm.
authors.affiliation: Faculty of Science, Charles University in Prague, Hlavova 2030, 128 43 Praha 2, Czech Republic.
authors.forename: Jiří
authors.initials: J
authors.lastname: Mosinger
authors.forename: Kamil
authors.initials: K
authors.lastname: Lang
authors.forename: Jiří
authors.initials: J
authors.lastname: Hostomský
authors.forename: Jiří
authors.initials: J
authors.lastname: Franc
authors.forename: Jan
authors.initials: J
authors.lastname: Sýkora
authors.forename: Martin
authors.initials: M
authors.lastname: Hof
authors.forename: Pavel
authors.initials: P
authors.lastname: Kubát
mesh_terms: D005453:Fluorescence; D008856:Microscopy, Fluorescence; D057139:Nanofibers / Q000737:chemistry*; D010316:Particle Size; D011108:Polymers / Q000737:chemistry*; D026082:Singlet Oxygen / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors
chemical_list: D011108:Polymers; D026082:Singlet Oxygen