4 research outputs found
A Dual Fluorescence–Spin Label Probe for Visualization and Quantification of Target Molecules in Tissue by Multiplexed FLIM–EPR Spectroscopy
Simultaneous visualization and concentration quantification of molecules in biological tissue is an important though challenging goal. The advantages of fluorescence lifetime imaging microscopy (FLIM) for visualization, and electron paramagnetic resonance (EPR) spectroscopy for quantification are complementary. Their combination in a multiplexed approach promises a successful but ambitious strategy because of spin label-mediated fluorescence quenching. Here, we solved this problem and present the molecular design of a dual label (DL) compound comprising a highly fluorescent dye together with an EPR spin probe, which also renders the fluorescence lifetime to be concentration sensitive. The DL can easily be coupled to the biomolecule of choice, enabling in vivo and in vitro applications. This novel approach paves the way for elegant studies ranging from fundamental biological investigations to preclinical drug research, as shown in proof-of-principle penetration experiments in human skin ex vivo
A Dual Fluorescence–Spin Label Probe for Visualization and Quantification of Target Molecules in Tissue by Multiplexed FLIM–EPR Spectroscopy
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