TY - JOUR

T1 - Photochemical degradation of trypan blue

AU - Brockman, Tobias

AU - Blanchard, Veronique

AU - Heretsch, Philipp

AU - Brockmann, Claudia

AU - Bertelmann, Eckart

N1 - Funding information:Dr.TobiasBrockmannandDr.Claudia BrockmannareparticipantsintheBIH–Charite ´ ClinicalScientistProgramfundedbytheCharite ´ – Universita ¨tsmedizinBerlinandtheBerlinInstitute ofHealth.Noneoftheauthorshasafinancialand proprietaryinterestinaproductorlackthereof.We acknowledgesupportfromtheGermanResearch Foundation(DFG)andtheOpenAccessPublication Dr. Tobias Brockmann and Dr. Claudia Brockmann are participants in the BIH – Charité Clinical Scientist Program funded by the Charité – Universitätsmedizin Berlin and the Berlin Institute of Health. None of the authors has a financial and proprietary interest in a product or lack thereof. We acknowledge support from the German Research Foundation (DFG) and the Open Access Publication Fund of Charité – Universitätsmedizin Berlin. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

PY - 2018/4/10

Y1 - 2018/4/10

N2 - Purpose To investigate the photochemical degradation of trypan blue (TB) and to identify decomposition products. Methods Defined solution samples of TB and a mixture with lutein/zeaxanthin were exposed to blue light. Thermal degradation processes were ruled out using controls not subjected to irradiation. All samples were analyzed using optical microscopy, UV/Vis spectroscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and nuclear magnetic resonance (NMR) spectrometry. Degradation kinetics were determined based on changes in absorbance; intermediates were identified by analyzing mass differences of characteristic fragment ion peaks within the fragmentation patterns, and assignments were verified by NMR. Results TB demonstrated a photochemical degradation, which can be triggered by lutein/zeaxanthin. Intermediates vary depending on the presence of lutein/zeaxanthin. The self-sensitized photodegradation of TB occurs under generation of dimethyl sulfate and presumed formation of phenol. In contrast, within the presence of lutein/zeaxanthin the decomposition of TB indicates the formation of methoxyamine and sulfonyl arin. Thermal degradation processes were not observed. Conclusions TB demonstrated a photodegradation that may be triggered by lutein/zeaxanthin and results in the formation of cytotoxic decomposition products. Our findings contribute to understand degradation mechanisms of TB and may elucidate previous clinical and experimental observations of cellular toxicity after TB application.

AB - Purpose To investigate the photochemical degradation of trypan blue (TB) and to identify decomposition products. Methods Defined solution samples of TB and a mixture with lutein/zeaxanthin were exposed to blue light. Thermal degradation processes were ruled out using controls not subjected to irradiation. All samples were analyzed using optical microscopy, UV/Vis spectroscopy, matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and nuclear magnetic resonance (NMR) spectrometry. Degradation kinetics were determined based on changes in absorbance; intermediates were identified by analyzing mass differences of characteristic fragment ion peaks within the fragmentation patterns, and assignments were verified by NMR. Results TB demonstrated a photochemical degradation, which can be triggered by lutein/zeaxanthin. Intermediates vary depending on the presence of lutein/zeaxanthin. The self-sensitized photodegradation of TB occurs under generation of dimethyl sulfate and presumed formation of phenol. In contrast, within the presence of lutein/zeaxanthin the decomposition of TB indicates the formation of methoxyamine and sulfonyl arin. Thermal degradation processes were not observed. Conclusions TB demonstrated a photodegradation that may be triggered by lutein/zeaxanthin and results in the formation of cytotoxic decomposition products. Our findings contribute to understand degradation mechanisms of TB and may elucidate previous clinical and experimental observations of cellular toxicity after TB application.

UR - http://www.scopus.com/inward/record.url?scp=85045145485&partnerID=8YFLogxK

U2 - 10.1371/journal.pone.0195849

DO - 10.1371/journal.pone.0195849

M3 - Article

VL - 13

JO - PLOS ONE

JF - PLOS ONE

SN - 1932-6203

IS - 4

M1 - e0195849

ER -