title: MALDI-TOF mass spectrometric analysis for the characterization of the 5,10,15,20-tetrakis- (m-hydroxyphenyl)bacteriochlorin (m-THPBC) photoproducts in biological environment.
abstract: Photoproducts formation upon irradiation (739 nm) of 5,10,15,20-tetrakis(m-hydroxyphenyl)bacteriochlorin (m-THPBC) in phosphate buffer saline (PBS) supplemented with human serum albumin (HSA) were studied by means of absorption spectroscopy and MALDI-TOF mass spectrometry. The experiments were performed with a freshly prepared PBS-HSA solution of m-THPBC and with a PBS-HSA m-THPBC solution incubated for 6 h at 37 degrees C. The incubation of m-THPBC solution leads to the dye monomerisation, whereas in the freshly prepared solution, m-THPBC is under an aggregated form. Regardless of the incubation condition, photobleaching experiments carried out by absorption spectroscopy demonstrate the degradation of the photosensitizer and its phototransformation in m-THPC. Moreover, m-THPC was the sole photoproduct detected using absorption spectroscopy. Together with a degradation of m-THPBC and formation of m-THPC, MALDI-TOF mass spectrometry evidenced several other photoinduced modifications. Photoproducts such as dihydroxy m-THPBC and dihydroxy m-THPC were detected in both conditions; however, the formation of hydroxylated photoproducts was significantly greater in incubated solution. In addition, small molecules arising from the degradation of the photosensitizer and identified as dipyrin derivatives and dipyrrolic synthon were observed.
authors.affiliation: Centre Alexis Vautrin, CRAN CNRS UMR 7039 INPL UHP, Vandoeuvre les Nancy, France. h.lassalle@nancy.fnclcc.fr
authors.forename: Henri-Pierre
authors.initials: HP
authors.lastname: Lassalle
authors.forename: Natacha
authors.initials: N
authors.lastname: Lourette
authors.forename: Benoît
authors.initials: B
authors.lastname: Maunit
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Muller
authors.forename: François
authors.initials: F
authors.lastname: Guillemin
authors.forename: Lina
authors.initials: L
authors.lastname: Bezdetnaya-Bolotine
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D006801:Humans; D008027:Light; D038761:Photobleaching; D010778:Photochemotherapy; D011166:Porphyrins / Q000737:chemistry* / Q000528:radiation effects; D011838:Radiation-Sensitizing Agents / Q000737:chemistry* / Q000528:radiation effects; D012709:Serum Albumin / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: C414352:5,10,15,20-tetrakis(m-hydroxyphenyl)bacteriochlorin; D011166:Porphyrins; D011838:Radiation-Sensitizing Agents; D012709:Serum Albumin