Abstract
Spectroscopic studies were carried out on the photosensitizer disulphonated aluminium phthalocyanine (AlS2Pc) which has prospective applications in photodynamic therapy. The fluorescence lifetimes of AlS2Pc were measured in a range of model systems and cultured leukaemic cells using laser excitation and time-correlated, single-photon-counting detection. In an investigation of non-covalent protein binding, we studied AlS2Pc in the presence of human serum albumin (HSA) in 0.1 M phosphate-buffered saline at pH 7.4. On addition of excess concentrations of HSA, small red shifts in the fluorescence and absorbance spectra were observed, together with an increase in fluorescence polarization anisotropy, consistent with binding of the phthalocyanine. Fluorescence decays could be resolved into two lifetimes for bound AlS2Pc with a dominant component of 5.5 ns and a minor component of 1 ns. Fluorescence imaging and time-resolved microfluorometry were carried out on intracellular AlS2Pc using leukaemic K562 cells. Microscopic imaging with a charge-coupled device (CCD) camera revealed that AlS2Pc fluorescence predominated in a discrete perinuclear region which was then probed selectively by a focused laser spot for fluorescence lifetime measurements. Bi-exponential decays with lifetime components of 6.1 and 2.2 ns were observed. On irradiation at 633 nm, the fluorescence intensity increased initially and subsequently declined due to photodegradation.
| Original language | English |
|---|---|
| Pages (from-to) | 105-117 |
| Number of pages | 13 |
| Journal | Journal of Photochemistry and Photobiology B: Biology |
| Volume | 22 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - 1994 |
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Keywords
- Fluorescence imaging
- Fluorescence lifetime
- Photodynamic therapy
- Phthalocyanine
ASJC Scopus subject areas
- Plant Science
- Bioengineering
- Physical and Theoretical Chemistry
Cite this
Time-resolved fluorescence spectroscopy and intracellular imaging of disulphonated aluminium phthalocyanine. / Ambroz, M.; MacRobertl, A. J.; Morgan, J.; Rumbles, Gary; Foley, M. S C; Phillips, D.
In: Journal of Photochemistry and Photobiology B: Biology, Vol. 22, No. 2, 1994, p. 105-117.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Time-resolved fluorescence spectroscopy and intracellular imaging of disulphonated aluminium phthalocyanine
AU - Ambroz, M.
AU - MacRobertl, A. J.
AU - Morgan, J.
AU - Rumbles, Gary
AU - Foley, M. S C
AU - Phillips, D.
PY - 1994
Y1 - 1994
N2 - Spectroscopic studies were carried out on the photosensitizer disulphonated aluminium phthalocyanine (AlS2Pc) which has prospective applications in photodynamic therapy. The fluorescence lifetimes of AlS2Pc were measured in a range of model systems and cultured leukaemic cells using laser excitation and time-correlated, single-photon-counting detection. In an investigation of non-covalent protein binding, we studied AlS2Pc in the presence of human serum albumin (HSA) in 0.1 M phosphate-buffered saline at pH 7.4. On addition of excess concentrations of HSA, small red shifts in the fluorescence and absorbance spectra were observed, together with an increase in fluorescence polarization anisotropy, consistent with binding of the phthalocyanine. Fluorescence decays could be resolved into two lifetimes for bound AlS2Pc with a dominant component of 5.5 ns and a minor component of 1 ns. Fluorescence imaging and time-resolved microfluorometry were carried out on intracellular AlS2Pc using leukaemic K562 cells. Microscopic imaging with a charge-coupled device (CCD) camera revealed that AlS2Pc fluorescence predominated in a discrete perinuclear region which was then probed selectively by a focused laser spot for fluorescence lifetime measurements. Bi-exponential decays with lifetime components of 6.1 and 2.2 ns were observed. On irradiation at 633 nm, the fluorescence intensity increased initially and subsequently declined due to photodegradation.
AB - Spectroscopic studies were carried out on the photosensitizer disulphonated aluminium phthalocyanine (AlS2Pc) which has prospective applications in photodynamic therapy. The fluorescence lifetimes of AlS2Pc were measured in a range of model systems and cultured leukaemic cells using laser excitation and time-correlated, single-photon-counting detection. In an investigation of non-covalent protein binding, we studied AlS2Pc in the presence of human serum albumin (HSA) in 0.1 M phosphate-buffered saline at pH 7.4. On addition of excess concentrations of HSA, small red shifts in the fluorescence and absorbance spectra were observed, together with an increase in fluorescence polarization anisotropy, consistent with binding of the phthalocyanine. Fluorescence decays could be resolved into two lifetimes for bound AlS2Pc with a dominant component of 5.5 ns and a minor component of 1 ns. Fluorescence imaging and time-resolved microfluorometry were carried out on intracellular AlS2Pc using leukaemic K562 cells. Microscopic imaging with a charge-coupled device (CCD) camera revealed that AlS2Pc fluorescence predominated in a discrete perinuclear region which was then probed selectively by a focused laser spot for fluorescence lifetime measurements. Bi-exponential decays with lifetime components of 6.1 and 2.2 ns were observed. On irradiation at 633 nm, the fluorescence intensity increased initially and subsequently declined due to photodegradation.
KW - Fluorescence imaging
KW - Fluorescence lifetime
KW - Photodynamic therapy
KW - Phthalocyanine
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UR - http://www.scopus.com/inward/citedby.url?scp=0028349923&partnerID=8YFLogxK
U2 - 10.1016/1011-1344(93)06955-3
DO - 10.1016/1011-1344(93)06955-3
M3 - Article
VL - 22
SP - 105
EP - 117
JO - Journal of Photochemistry and Photobiology B: Biology
JF - Journal of Photochemistry and Photobiology B: Biology
SN - 1011-1344
IS - 2
ER -