Biomedical Engineering Reference
In-Depth Information
Pc
Phthalocyanine
Pc
4
Silicon phthalocyanine 4
Pc
19
Silicon phthalocyanine 219
PDT
Photodynamic therapy
PEG
Polyethylene glycol
PFHA
Perfluoroheptanoic acid
PpIX
Protoporphyrin IX
PS
Photosensitizer
PdTPP
Pd-
meso
-Tetra(4-carboxyphenyl) porphyrin
PHPP
2,7,12,18-Tetramethyl-3,8-di(1-propoxyethyl)-13,17-bis-(3-hydroxypropyl)
porphyrin
PSS
Polystyrene sulfonic acid
RB
Rose Bengal
RNA
Ribonucleic acid
ROS
Reactive Oxygen Species
SWNTs
Single walled carbon nanotubes
TPP
Meso-tetraphenyl porphyrin
RNO
N,
N
-dimethyl-4-nitrosoaniline
SEM
Scanning Electron Microscopy
TEM
Transmission electron microscopy
TPA
Two-photon absorption
TEOS
Tetraethoxysilane
UV-Vis
Ultraviolet-visible
XRD
X-ray diffraction
ZnPc
Zinc(II) phthalocyanine
1
Introduction
Over the last few years, photodynamic therapy (PDT) has emerged as an alterna-
tive to chemo- and radiotherapy for the treatment of various diseases including
cancer (Maisch
2009
; Robertson et al.
2009
). It involves the use of light and pho-
tosensitizers (PS) that accumulate in the tumor tissue. Photosensitizer are drugs
that can transfer their energy from their triplet excited state to neighboring oxygen
molecules (Ortel et al.
2009
) when activated by light of a specific wavelength.
Singlet oxygen (
1
O
2
) and other cytotoxic Reactive Oxygen Species (ROS) are
formed and lead to the destruction of cancer cells by both apoptosis and necrosis.
The efficiency of PDT can be related to the formation of ROS and it is commonly
accepted that
1
O
2
is the main cytotoxic species that destroys tumour cells. PS
described so far in the literature present several disadvantages. Mainly, they are
hydrophobic or have a limited solubility in water and therefore aggregate in
aqueous media such as the blood compartment which leads to the modification of
their photophysical properties and particularly to the decrease of
1
O
2
quantum
yield. Moreover, in order to avoid destruction of healthy cells, PS are required to
Search WWH ::
Custom Search