Journal
JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
Volume 346, Issue -, Pages 452-461Publisher
ELSEVIER SCIENCE SA
DOI: 10.1016/j.jphotochem.2017.06.039
Keywords
Porphyrin; Magnetic nanoparticles; Photosensitizer; Photooxidation; Singlet oxygen; Photodynamic inactivation
Categories
Funding
- Consejo Nacional de Investigaciones Cientificas y Tecnicas (CONICET) of Argentina [PIP-2015 1122015 0100197 CO]
- SECYT Universidad Nacional de Rio Cuarto [PPI-2016 18/C460]
- Agencia Nacional de Promocion Cientifica y Tecnologica (FONCYT) of Argentina [PICT-2012 0714]
- CONICET
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Magnetic nanoparticles of Fe3O4 (MNP) were synthesized by co-precipitating Fe2+ and Fe3+ ions in an ammonia solution. This MNP was coated with silica using sodium metasilicate to obtain silica-coated MNP (MNPSi). Grafting of aminopropyl groups on MNP or MNPSi was performed with (3-aminopropyl) trimethoxysilane to form MNPNH2 or MNPSiNH2, respectively. 5,10,15,20-Tetrakis(4-carboxyphenyl) porphyrin (TCPP) was covalently bound onto the MNPNH2 or MNPSiNH2 via carbodiimide activation to obtain MNPNH-TPCC or MNPNH-TPCC, respectively. These MNP presented an average diameter of about 15 nm. UV-vis absorption spectra presented the characteristic Soret and Q bands of TCPP covalently linked to the nanoparticles. The MNP containing TCPP produced a high photodecomposition of 2,2(anthracene-9,10-diyl)bis(methylmalonate), which was used to detect singlet molecular oxygen O-2(1 Delta(g)) production in water. Moreover, these nanoparticles sensitized the photooxidation of L-tryptophan in water, mainly mediated by a type II photoprocess. Photoinactivation of microorganisms was investigated in Staphylococcus aureus, Escherichia coil and Candida albicans. In vitro experiments showed that photosensitized inactivation induced by MNPSiNH-TCPP improved with an increase of irradiation times. After 30 min irradiation, a 2.5 log reduction was found for S. aureus and C. albicans. Also, the last conditions produced a decrease of 3 log in E. coli. Similar result was obtained MNPNH-TCPP. However, the main difference between these nanoparticles as photosensitizer was found after recycling experiments. While the photoinactivation mediated by MNPNH-TCPP rapidly decrease after one cycle, MNPSiNH-TCPP was still efficient after three cycles of inactivation. Therefore, MNPSiNH-TCPP is an interesting and versatile photodynamic active material to eradicate microorganisms. (C) 2017 Elsevier B.V. All rights reserved.
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