11 research outputs found
A organização do conhecimento arquivístico: perspectivas de renovação a partir das abordagens científicas canadenses
Consolidation of magnesium and magnesium-quasicrystal composites through high‑pressure torsion
Combining Magnetic Hyperthermia and Photodynamic Therapy for Tumor Ablation with Photoresponsive Magnetic Liposomes
Wear Resistance of Boron-Modified Supermartensitic Stainless Steel Coatings Produced by High-Velocity Oxygen Fuel Process
Photodynamic therapy for cancer: principles, clinical applications and nano technological approaches
Photodynamic therapy (PDT) is a clinically approved, minimally
invasive procedure that can exert a cytotoxic activity toward malignant
cells. The procedure involves administration of a photosensitizer (PS)
followed by irradiation with light at wavelengths within of the PS
absorption band. In the presence of oxygen, a series of events lead to
direct tumor cell death, damage to the microvasculature, and induction
of a local inflammatory reaction. Clinical studies reveal that PDT can
be curative, particularly in early stage tumors, can prolong survival in
patients with inoperable cancers, and can significantly improve quality of
life. Unfortunately, most PS lack specificity for tumor cells and this can
result in undesirable side effects in healthy tissues. Furthermore, due to
their mostly planar structure, PS form aggregates with low photoactivity
in an aqueous environment.
Nanotechnology offers a great opportunity in PDT based on the concept
that a nanocarrier can drive therapeutic concentrations of PS to the tumor
cells without generating any harmful effect in vivo. Currently, several
nanoscale carriers made of different materials such as lipids, polymers,
metals, and inorganic materials have been proposed in nano-PDT. Each
type of system highlights pros and cons and should be selected on the
basis of delivery requirements.
In the following, we describe the principle of PDT and its application in
the treatment of cancer. Then, we illustrate the main systems proposed
for nano-PDT that demonstrated potential in preclinical models together
with emerging concepts for their advanced design