title: Potency of different red light sources in photodynamic induction of cell death in a squamous cell carcinoma cell line.
abstract: LED illumination systems were found to be more efficacious than broad spectrum lamps in recent phase III trials on photodynamic treatment of actinic keratosis. However, a detailed comparison of the light doses emitted at the appropriate spectral range and its correlation to photodynamic effects is thus far not available for the most frequently used devices. Here, we compared the spectral emissions of three different PDT lamps with their potency of inducing cell death in ALA-loaded A431 cells, including a new system equipped with more advanced LEDs matching the photosensitizer absorption peak more precisely and emitting more homogeneous light over time. Cells were exposed to two different ALA concentrations, incubated for 1 or 3h and then illuminated by one of two different LED or a broad-spectrum system at four different light doses, whereupon viability was assessed. Maximal doses were selected in accordance to clinically applied light doses in recent phase III studies and the manufacturers' recommendations. The data gathered here clearly demonstrate that the two LED systems were significantly more effective in inducing cell death than the broad spectrum system. Most efficient was the newer LED system, in agreement with emission parameters that more accurately corresponded to the photosensitizer's absorption peak.
authors.affiliation: Biofrontera Pharma GmbH, Hemmelrather Weg 201, 51377 Leverkusen, Germany. Electronic address: b.novak@biofrontera.com.
authors.forename: Ben
authors.initials: B
authors.lastname: Novak
authors.affiliation: Biofrontera AG, Hemmelrather Weg 201, 51377 Leverkusen, Germany.
authors.forename: Monika
authors.initials: M
authors.lastname: Peteja
authors.affiliation: Scemtec Sensor Technology, Gewerbeparkstraße 20, 51580 Reichshof, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Brueck
authors.affiliation: Biofrontera AG, Hemmelrather Weg 201, 51377 Leverkusen, Germany.
authors.forename: Hermann
authors.initials: H
authors.lastname: Luebbert
mesh_terms: D000622:Aminolevulinic Acid / Q000627:therapeutic use; D002294:Carcinoma, Squamous Cell / Q000628:therapy*; D045744:Cell Line, Tumor; D003116:Color; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D010778:Photochemotherapy; D012878:Skin Neoplasms / Q000628:therapy*
chemical_list: D000622:Aminolevulinic Acid
keywords: Cell death; Light sources; Photodynamic therapy; Squamous cell carcinoma