TY  - JOUR
A1  - Draffehn, Soeren
A1  - Kumke, Michael Uwe
T1  - Monitoring the Collapse of pH-Sensitive Liposomal Nanocarriers and Environmental pH Simultaneously: A Fluorescence-Based Approach
JF  - Molecular pharmaceutics
N2  - 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.
KW  - pH-sensitive liposome
KW  - drug carrier system
KW  - selective drug release
KW  - intracellular pH indicator
KW  - time-resolved fluorescence spectroscopy
KW  - fluorescence anisotropy
KW  - fluorescence correlation spectroscopy
Y1  - 2016
U6  - https://doi.org/10.1021/acs.molpharmaceut.5b00064
SN  - 1543-8384
VL  - 13
SP  - 1608
EP  - 1617
PB  - American Chemical Society
CY  - Washington
ER  -