3 research outputs found
Near-Infrared Dye-Conjugated Amphiphilic Hyaluronic Acid Derivatives as a Dual Contrast Agent for In Vivo Optical and Photoacoustic Tumor Imaging
Amphiphilic
hyaluronic acid (HA) derivatives bearing hydrophobic
indocyanine green dye derivatives and hydrophilic polyÂ(ethylene glycol)
were synthesized through the use of condensation and copper-catalyzed
click cyclization reactions. The amphiphilic HA derivatives dissolved
in water and formed self-assemblies in which the near-infrared dyes
were tightly packed and arranged to form dimers or H-aggregates. By
irradiating an aqueous solution of HA derivatives with near-infrared
light, photoacoustic signals were detected along with fluorescence
emission. Self-assemblies consisting of HA derivatives could smoothly
accumulate in tumor tissues by passive tumor targeting. By utilizing
HA derivatives as a contrast agent, tumor sites were clearly visualized
by optical imaging as well as by photoacoustic tomography
Polymeric Self-Assemblies with Boron-Containing Near-Infrared Dye Dimers for Photoacoustic Imaging Probes
Polymers
containing pyrrolopyrrole aza-BODIPY (PPAB) and thiophene-bridged
BODIPY dimers (TBD) having polyÂ(ethylene glycol) (PEG) or PEGylated
hyaluronic acid (HA) were prepared by facile conjugation approaches.
Self-assemblies consisting of TBD-conjugated polymers more efficiently
generated photoacoustic (PA) signals than PPAB–PEG conjugate
upon irradiation with near-infrared pulsed laser light. Among dye-conjugated
polymers examined, TBD-HA-PEG conjugates efficiently generated photoacoustic
signals, 1.49–1.83 times stronger than that of commercially
available indocyanine green (ICG). We found that the following two
factors are essential to enhance PA signals from self-assemblies:
(1) the formation of strongly interacting TBD aggregates and (2) enhancement
of the elastic modulus of self-assemblies by conjugating TBDs with
HA. TBD-conjugated HA derivatives circulated in blood vessels for
a longer time (15.6 ± 4.9% injected dose (ID) in blood 24 h after
injection) and more specifically accumulated in tumor tissues (17.8 ±
3.5% ID/g in tumor 24 h after injection) than ICG-conjugated HA derivatives,
visualizing a tumor site more clearly. The cell uptake experiment
of dye–HA conjugates indicates that ICG-conjugated polymers
internalized into cells or merged with cell walls to emit strong fluorescence,
while TBD-conjugated polymers were not internalized into cells. Because
the disassembly of the TBD-conjugated HA derivatives is suppressed,
aggregated TBDs emit weak fluorescence but efficiently generate strong
PA signals in tumor tissues
Near-Infrared Dye-Conjugated Amphiphilic Hyaluronic Acid Derivatives as a Dual Contrast Agent for In Vivo Optical and Photoacoustic Tumor Imaging
Amphiphilic
hyaluronic acid (HA) derivatives bearing hydrophobic
indocyanine green dye derivatives and hydrophilic polyÂ(ethylene glycol)
were synthesized through the use of condensation and copper-catalyzed
click cyclization reactions. The amphiphilic HA derivatives dissolved
in water and formed self-assemblies in which the near-infrared dyes
were tightly packed and arranged to form dimers or H-aggregates. By
irradiating an aqueous solution of HA derivatives with near-infrared
light, photoacoustic signals were detected along with fluorescence
emission. Self-assemblies consisting of HA derivatives could smoothly
accumulate in tumor tissues by passive tumor targeting. By utilizing
HA derivatives as a contrast agent, tumor sites were clearly visualized
by optical imaging as well as by photoacoustic tomography