TY - JOUR
T1 - Fluorescence lifetime imaging and FRET-induced intracellular redistribution of tat-conjugated quantum dot nanoparticles through interaction with a phthalocyanine photosensitiser
AU - Yaghini, Elnaz
AU - Giuntini, Francesca
AU - Eggleston, Ian M.
AU - Suhling, Klaus
AU - Seifalian, Alexander M.
AU - MacRobert, Alexander J.
PY - 2014/2/26
Y1 - 2014/2/26
N2 - The interaction of Tat-conjugated PEGylated CdSe/ZnS quantum dots (QD) with the amphiphilic disulfonated aluminium phthalocyanine photosensitiser is investigated in aqueous solution and in a human breast cancer cell line. In aqueous solution, the QDs and phthalocyanine form stable nanocomposites. Using steady-state and time-resolved fluorescence measurements combined with singlet oxygen detection, efficient Förster resonance energy transfer (FRET) is observed with the QDs acting as donors, and the phthalocyanine photosensitiser, which mediates production of singlet oxygen, as acceptors. In cells, the Tat-conjugated QDs localise in lysosomes and the QD fluorescence lifetimes are close to values observed in aqueous solution. Strong FRET-induced quenching of the QD lifetime is observed in cells incubated with the nanocomposites using fluorescence lifetime imaging microscopy (FLIM). Using excitation of the QDs at wavelengths where phthalocyanine absorption is negligible, FRET-induced release of QDs from endo/lysosomes is confirmed using confocal imaging and FLIM, which is attributed to photooxidative damage to the endo/lysosomal membranes mediated by the phthalocyanine acceptor. Phototriggered release of TAT-conjugated quantum dots complexed with a phthalocyanine photosensitiser from endo/lysosomes. Membrane photooxidation and ensuing rupture is mediated by singlet oxygen generated via FRET to the phthalocyanine acceptor from the quantum dot (QD) donor.
AB - The interaction of Tat-conjugated PEGylated CdSe/ZnS quantum dots (QD) with the amphiphilic disulfonated aluminium phthalocyanine photosensitiser is investigated in aqueous solution and in a human breast cancer cell line. In aqueous solution, the QDs and phthalocyanine form stable nanocomposites. Using steady-state and time-resolved fluorescence measurements combined with singlet oxygen detection, efficient Förster resonance energy transfer (FRET) is observed with the QDs acting as donors, and the phthalocyanine photosensitiser, which mediates production of singlet oxygen, as acceptors. In cells, the Tat-conjugated QDs localise in lysosomes and the QD fluorescence lifetimes are close to values observed in aqueous solution. Strong FRET-induced quenching of the QD lifetime is observed in cells incubated with the nanocomposites using fluorescence lifetime imaging microscopy (FLIM). Using excitation of the QDs at wavelengths where phthalocyanine absorption is negligible, FRET-induced release of QDs from endo/lysosomes is confirmed using confocal imaging and FLIM, which is attributed to photooxidative damage to the endo/lysosomal membranes mediated by the phthalocyanine acceptor. Phototriggered release of TAT-conjugated quantum dots complexed with a phthalocyanine photosensitiser from endo/lysosomes. Membrane photooxidation and ensuing rupture is mediated by singlet oxygen generated via FRET to the phthalocyanine acceptor from the quantum dot (QD) donor.
KW - fluorescence lifetime imaging microscopy (FLIM)
KW - förster resonance energy transfer (FRET)
KW - photochemical internalization (PCI)
KW - photodynamic therapy
KW - quantum dots
UR - http://www.scopus.com/inward/record.url?scp=84894274650&partnerID=8YFLogxK
U2 - 10.1002/smll.201301459
DO - 10.1002/smll.201301459
M3 - Article
C2 - 24031023
AN - SCOPUS:84894274650
SN - 1613-6810
VL - 10
SP - 782
EP - 792
JO - Small
JF - Small
IS - 4
ER -
