1 research outputs found
Monitoring the Collapse of pH-Sensitive Liposomal Nanocarriers and Environmental pH Simultaneously: A Fluorescence-Based Approach
Nowadays,
the encapsulation of therapeutic compounds in so-called
carrier systems is a very smart method to achieve protection as well
as an improvement of their temporal and spatial distribution. After
the successful transport to the point of care, the delivery has to
be released under controlled conditions. To monitor the triggered
release from the carrier, we investigated different fluorescent probes
regarding their response to the pH-induced collapse of pH-sensitive
liposomes (pHSLip), which occurs when the environmental pH falls below
a critical value. Depending on the probe, the fluorescence decay time
as well as fluorescence anisotropy can be used equally as key parameters
for monitoring the collapse. Especially the application of a fluorescein
labeled fatty acid (fPA) enabled the monitoring of the pHSLips collapse
and the pH of its microenvironment simultaneously without interference.
Varying the pH in the range of 3 < pH < 9, anisotropy data revealed
the critical pH value at which the collapse of the pHSLips occurs.
Complementary methods, e.g., fluorescence correlation spectroscopy
and dynamic light scattering, supported the analysis based on the
decay time and anisotropy. Additional experiments with varying incubation
times yielded information on the kinetics of the liposomal collapse