Potentiation of antimicrobial photodynamic inactivation mediated by a cationic fullerene by added iodide: in vitro and in vivo studies.
BACKGROUND
Antimicrobial photodynamic inactivation with fullerenes bearing cationic charges may overcome resistant microbes.


RESULTS
We synthesized C60-fullerene (LC16) bearing decaquaternary chain and deca-tertiary-amino groups that facilitates electron-transfer reactions via the photoexcited fullerene. Addition of the harmless salt, potassium iodide (10 mM) potentiated the ultraviolet A (UVA) or white light-mediated killing of Gram-negative bacteria Acinetobacter baumannii, Gram-positive methicillin-resistant Staphylococcus aureus and fungal yeast Candida albicans by 1-2+ logs. Mouse model infected with bioluminescent Acinetobacter baumannii gave increased loss of bioluminescence when iodide (10 mM) was combined with LC16 and UVA/white light.


CONCLUSIONS
The mechanism may involve photoinduced electron reduction of (1)(C60>)* or (3)(C60>)* by iodide producing I· or I2 followed by subsequent intermolecular electron-transfer events of (C60>)-· to produce reactive radicals.
Department of Burn & Plastic Surgery, Guangzhou Red Cross Hospital, Jinan University, Guangzhou, China.
Yunsong
Y
Zhang
Tianhong
T
Dai
Min
M
Wang
Daniela
D
Vecchio
Long Y
LY
Chiang
Michael R
MR
Hamblin
D000151:Acinetobacter Infections / Q000188:drug therapy; D040981:Acinetobacter baumannii / Q000187:drug effects; D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D002176:Candida albicans / Q000187:drug effects; D002177:Candidiasis / Q000188:drug therapy; D004926:Escherichia coli / Q000187:drug effects; D005260:Female; D037741:Fullerenes / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D006801:Humans; D007454:Iodides / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D013203:Staphylococcal Infections / Q000188:drug therapy
D000890:Anti-Infective Agents; D037741:Fullerenes; D007454:Iodides; D017319:Photosensitizing Agents; C069837:fullerene C60
antimicrobial photodynamic therapy; bioluminescent bacteria; decacationic fullerene; decatertiary-amine chain; in vivo infection model; iodide potentiation