1 research outputs found
FRET Imaging Approaches for <i>in Vitro</i> and <i>in Vivo</i> Characterization of Synthetic Lipid Nanoparticles
DiI
and DiD, two fluorophores able to interact by FRET (Förster
resonance energy transfer), were coencapsulated in the core of lipid
nanocapsules (LNCs) and nanoemulsions (LNEs), lipophilic reservoirs
for the delivery of drugs. The ability of FRET imaging to provide
information on the kinetics of dissociation of the nanoparticles in
the presence of bovine serum albumin (BSA) or whole serum, or after
incubation with cancer cells, and after systemic administration in
tumor-bearing mice, was studied. Both microscopic and macroscopic
imaging was performed to determine the behavior of the nanostructures
in a biological environment. When 2 mg/mL FRET LNEs or LNCs were dispersed
in buffer, in the presence of unloaded nanoparticles, BSA, or in whole
serum, the presence of serum was the most active in destroying the
particles. This occurred immediately with a diminution of 20% of FRET,
then slowly, ending up with still 30% intact nanoparticles at 24 h.
LNCs were internalized rapidly in cultured cells with the FRET signal
decreasing within the first minutes of incubation, and then a plateau
was reached and LNCs remained intact during 3 h. In contrast, LNEs
were poorly internalized and were rapidly dissociated after internalization.
Following their iv injection, LNCs appeared very stable in subcutaneous
tumors implanted in mice. Intact particles were found using microscopic
FRET determination on tumor sections 24 h after injection, that correlated
well with the 8% calculated noninvasively on live animals. FRET investigations
showed the potential to determine valid and reliable information about <i>in vitro</i> and <i>in vivo</i> behavior of nanoparticles