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Updated: Apr 28, 2026

LED-Based In Vitro Screening for Assessing Photoactivable Molecules in Bacterial Photodynamic Inactivation
Published on: January 24, 2025
Photobiological characteristics of chlorophyll a derivatives as microbial PDT agents
Marciana P Uliana1, Layla Pires, Sebastião Pratavieira
1Instituto de Física de São Carlos - Universidade de São Paulo, Av: Trabalhador São Carlense, 400, São Carlos, São Paulo 13566-590, Brazil. cristina@ifsc.usp.br.
Abstract:
Chlorin-e6 (chl-e6) and a hydrogenated derivative (chl-e6H) were semi-synthesized, and their photophysical properties and photodynamic activity against Escherichia coli, Staphylococcus aureus and Candida albicans evaluated. Methyl pheophorbide-a (Mepheo-a) was obtained from S. maxima using methanolic extraction with acid catalysis (CH3OH–H2SO4). Chlorin-e6 was prepared from Mepheo-a by basic hydrolysis with H2O–acetone and NaOH. Hydrogenated Chlorin-e6 was synthesized by a similar procedure starting from the hydrogenated methyl pheophorbide-a (Mepheo-aH). Photophysical studies were performed in order to determine the singlet oxygen quantum yield of chl-e6H which is higher than that of chl-e6. The microorganism inactivation of chl-e6 and chl-e6H was investigated at two concentrations and three fluence levels. Both chl-e6 and chl-e6H showed microorganism inactivation against Gram-positive bacteria and a fungus.
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