Photodynamic performance of zinc phthalocyanine in HeLa cells: A comparison between DPCC liposomes and BSA as delivery systems.
Comparable intracellular concentrations (≈30pmol/10(6) cells) of bovine serum albumin-ZnPc (BSA) adduct outperformed dipalmitoyl-phosphatidyl-choline (DPPC) liposomes containing ZnPc at photodynamic-killing of human cervical cancer cells (HeLa) after only 15min of irradiation using red light (λ>620nm, 30W/cm(2)). This result could not be simply explained in terms of dye aggregation within the carrier, since in the liposomes the dye was considerably less aggregated than in bovine serum albumin, formulation that was capable to induce cell apoptosis upon red light exposure. Thus, using specific organelle staining, our cumulative data points towards intrinsic differences in intra-cellular localization depending on the cargo vehicle used, being ZnPc:BSA preferentially located in the near vicinity of the nucleus and in the Golgi structures, while the liposomal formulation ZnPc:DPPC was preferentially located in cellular membrane and cytoplasm. In addition to those differences, using real-time advanced fluorescence lifetime imaging of HeLa cells loaded with the photosensitizer contained in the different vehicles, we have found that only for the ZnPc:BSA formulation, there was no significant changes in the fluorescence lifetime of the photosensitizer inside the cells. This contrasts with the in situ≈two-fold reduction of the fluorescence lifetime measured for the liposomal ZnPc formulation. Those observations point towards the superiority of the protein to preserve dye aggregation, and its photochemical activity, post-cell uptake, demonstrating the pivotal role of the delivery vehicle at determining the ultimate fate of a photosensitizer.
Facultad de Ciencias Básicas, Escuela de Ciencias Químicas, Universidad Pedagógica y Tecnológica de Colombia-UPTC, Colombia.
Angélica
A
M Garcia
Department of Chemistry and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, K1N 6N5, Canada.
Hasitha
H
de Alwis Weerasekera
Department of Chemistry and Centre for Catalysis Research and Innovation, University of Ottawa, 10 Marie Curie, Ottawa, K1N 6N5, Canada.
Spencer P
SP
Pitre
Division of Cardiac Surgery Research, Bio-Nanomaterials Chemistry and Engineering Laboratory, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, Ontario, K1Y 4W7, Canada.
Brian
B
McNeill
Departamento de ciencias del ambiente, Facultad de Química y Biología, Universidad de Santiago de Chile, (USACH), Santiago, Chile.
Eduardo
E
Lissi
Departamento de Química Física, Facultad de Química, Pontificia Universidad Católica de Chile, Santiago, Chile. Electronic address: aedwards@uc.cl.
Ana M
AM
Edwards
Division of Cardiac Surgery Research, Bio-Nanomaterials Chemistry and Engineering Laboratory, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, Ontario, K1Y 4W7, Canada; Department of Biochemistry, Microbiology, and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada. Electronic address: ealarcon@ottawaheart.ca.
Emilio I
EI
Alarcon
D015060:1,2-Dipalmitoylphosphatidylcholine / Q000737:chemistry*; D000818:Animals; D001692:Biological Transport; D002417:Cattle; D006367:HeLa Cells; D006801:Humans; D007211:Indoles / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism / Q000528:radiation effects; D054833:Isoindoles; D008081:Liposomes; D009942:Organometallic Compounds / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D017319:Photosensitizing Agents / Q000008:administration & dosage* / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D012710:Serum Albumin, Bovine / Q000737:chemistry*; D017967:Zinc Compounds
D007211:Indoles; D054833:Isoindoles; D008081:Liposomes; D009942:Organometallic Compounds; D017319:Photosensitizing Agents; D017967:Zinc Compounds; C052159:Zn(II)-phthalocyanine; D015060:1,2-Dipalmitoylphosphatidylcholine; D012710:Serum Albumin, Bovine
Albumin proteins; FLIM; Liposomes; Photodynamic therapy