title: In vitro studies of different irradiation conditions for Photodynamic inactivation of Helicobacter pylori.
abstract: Helicobacter pylori (HP) infections are considered to be the main cause for chronic gastritis and gastric ulcers, whereby more than half of the world's population is nowadays infected. The increased use of antibiotics is leading to an enhanced resistance. Photodynamic inactivation of bacteria seems to be a potential alternative for antibiotic therapies. In our study we used the photosensitizer Chlorin e6 (Ce6) in combination with red light-emitting diodes to inactivate HP in vitro. Ce6 uptake is determined by spectroscopy. Furthermore diverse experiments of different concentrations in the range of 0-100 μM of the photosensitizer and exposure times up to 300 s are carried out in order to find optimal irradiation parameters (wavelength: 660 nm, power density: 9 mW/cm(2), absorbed dose: up to 2.7 J/cm(2)). The data show a significant reduction after already a few seconds of illumination, even with a low Ce6 concentration in the sub-μM-region. At a concentration of 100 μM a nearly total inactivation (6-log10-reduction) of HP was achieved within 60s of irradiation.
authors.affiliation: Department of Physics, University of Kaiserslautern, Germany. Electronic address: casimon@rhrk.uni-kl.de.
authors.forename: C
authors.initials: C
authors.lastname: Simon
authors.affiliation: Institute of Laboratory Medicine, Westpfalz-Klinikum GmbH, Kaiserslautern, Germany; ApoCare Pharma GmbH, Bielefeld, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Mohrbacher
authors.affiliation: ApoCare Pharma GmbH, Bielefeld, Germany.
authors.forename: D
authors.initials: D
authors.lastname: Hüttenberger
authors.affiliation: Institute of Laboratory Medicine, Westpfalz-Klinikum GmbH, Kaiserslautern, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Bauer-Marschall
authors.affiliation: Institute of Laboratory Medicine, Westpfalz-Klinikum GmbH, Kaiserslautern, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Krickhahn
authors.affiliation: Institute of Laboratory Medicine, Westpfalz-Klinikum GmbH, Kaiserslautern, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Stachon
authors.affiliation: Department of Physics, University of Kaiserslautern, Germany.
authors.forename: H-J
authors.initials: HJ
authors.lastname: Foth
mesh_terms: D002735:Chlorophyllides; D016480:Helicobacter pylori / Q000187:drug effects / Q000528:radiation effects*; D008027:Light; D017319:Photosensitizing Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D011166:Porphyrins / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D013053:Spectrophotometry; D013997:Time Factors
chemical_list: D002735:Chlorophyllides; D017319:Photosensitizing Agents; D011166:Porphyrins; C062985:phytochlorin