title: Controlled intracellular generation of reactive oxygen species in human mesenchymal stem cells using porphyrin conjugated nanoparticles.
abstract: Nanoparticles capable of generating controlled amounts of intracellular reactive oxygen species (ROS), that advance the study of oxidative stress and cellular communication, were synthesized by functionalizing polyacrylamide nanoparticles with zinc(II) porphyrin photosensitisers. Controlled ROS production was demonstrated in human mesenchymal stem cells (hMSCs) through (1) production of nanoparticles functionalized with varying percentages of Zn(II) porphyrin and (2) modulating the number of doses of excitation light to internalized nanoparticles. hMSCs challenged with nanoparticles functionalized with increasing percentages of Zn(II) porphyrin and high numbers of irradiations of excitation light were found to generate greater amounts of ROS. A novel dye, which is transformed into fluorescent 7-hydroxy-4-trifluoromethyl-coumarin in the presence of hydrogen peroxide, provided an indirect indicator for cumulative ROS production. The mitochondrial membrane potential was monitored to investigate the destructive effect of increased intracellular ROS production. Flow cytometric analysis of nanoparticle treated hMSCs suggested irradiation with excitation light signalled controlled apoptotic cell death, rather than uncontrolled necrotic cell death. Increased intracellular ROS production did not induce phenotypic changes in hMSC subcultures.
authors.affiliation: Laboratory of Biophysics and Surface Analysis, School of Pharmacy, Boots Science Building, University of Nottingham, Nottingham, NG7 2RD, UK. Jon.Aylott@nottingham.ac.uk.
authors.forename: Andrea S
authors.initials: AS
authors.lastname: Lavado
authors.forename: Veeren M
authors.initials: VM
authors.lastname: Chauhan
authors.forename: Amer Alhaj
authors.initials: AA
authors.lastname: Zen
authors.forename: Francesca
authors.initials: F
authors.lastname: Giuntini
authors.forename: D Rhodri E
authors.initials: DR
authors.lastname: Jones
authors.forename: Ross W
authors.initials: RW
authors.lastname: Boyle
authors.forename: Andrew
authors.initials: A
authors.lastname: Beeby
authors.forename: Weng C
authors.initials: WC
authors.lastname: Chan
authors.forename: Jonathan W
authors.initials: JW
authors.lastname: Aylott
mesh_terms: D017209:Apoptosis / Q000187:drug effects; D002460:Cell Line; D003374:Coumarins / Q000737:chemistry; D006801:Humans; D006861:Hydrogen Peroxide / Q000737:chemistry; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D053758:Nanoparticles / Q000737:chemistry*; D017319:Photosensitizing Agents / Q000737:chemistry* / Q000494:pharmacology; D011166:Porphyrins / Q000737:chemistry; D017382:Reactive Oxygen Species / Q000378:metabolism*; D015032:Zinc / Q000737:chemistry
chemical_list: D003374:Coumarins; D017319:Photosensitizing Agents; D011166:Porphyrins; D017382:Reactive Oxygen Species; C030123:coumarin; D006861:Hydrogen Peroxide; D015032:Zinc