title: Electroporation enhances antimicrobial photodynamic therapy mediated by the hydrophobic photosensitizer, hypericin.
abstract: The effective transport of photosensitizers (PS) across the membrane and the intracellular accumulation of PS are the most crucial elements in antimicrobial photodynamic therapy (aPDT). However, due to the morphological complexity of Gram-negative bacteria the penetration of PS is limited, especially hydrophobic PS. Electroporation (EP) could increase the effectiveness of aPDT, by promoting the formation of transient pores that enhance the permeability of the bacterial membrane to PS. In this study we evaluated the combination of aPDT mediated by the hydrophobic PS, hypericin and EP (aPDT/EP) against Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli. These bacteria were exposed to light (590 nm) in the presence of hypericin (4 μM), following electroporation. The results showed that aPDT/EP inactivated 3.67 logs more E. coli and 2.65 logs more S. aureus than aPDT alone. Based on these results we suggest that EP can potentiate the aPDT effect.
authors.affiliation: Programa de Pós-Graduação Interunidades em Bioengenharia - EESC/FMRP/IQSC, Universidade de São Paulo, São Carlos, SP, Brazil; Wellman Center for Photomedicine, Massachusetts General Hospital, Boston, MA, USA; Department of Dermatology, Harvard Medical School, Boston, MA, USA.
authors.forename: Wanessa de Cássia Martins Antunes
authors.initials: Wde C
authors.lastname: de Melo
authors.forename: Alexander N
authors.initials: AN
authors.lastname: Lee
authors.forename: Janice Rodrigues
authors.initials: JR
authors.lastname: Perussi
authors.forename: Michael R
authors.initials: MR
authors.lastname: Hamblin
mesh_terms: D000873:Anthracenes; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D004203:Disinfection / Q000379:methods*; D018274:Electroporation / Q000379:methods*; D004926:Escherichia coli / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D057927:Hydrophobic and Hydrophilic Interactions; D010569:Perylene / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000737:chemistry; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000502:physiology / Q000528:radiation effects; D016896:Treatment Outcome
chemical_list: D000873:Anthracenes; D000900:Anti-Bacterial Agents; D017319:Photosensitizing Agents; D010569:Perylene; C004965:hypericin
keywords: Antimicrobial photodynamic therapy; E. coli; Electroporation; Hypericin; S. aureus