Conjugated polymers hold great promise for NIR-II fluorescence imaging (FI)-guided NIR-II photothermal therapy (PTT) due to the advantages of easily modified chemical structures and adjustable NIR absorption. However, to achieve...
Developing organic aggregation-induced emission luminogens
(AIEgens)
with a donor–acceptor–donor (D–A–D) structure
improves fluorescence imaging for biological applications due to their
deep tissue penetration, high fluorescence quantum yield, and good
biocompatibility. However, compared to the systematically well-explored
near-infrared-I (NIR-I, 650–900 nm) AIEgens, the research on
organic D–A–D-type near-infrared-II (NIR-II, 1000–1700
nm) AIEgens received a snub, by contrast, owing to their lack of diversity,
low AIE character, and poor tumor accumulation, which has become a
bottleneck in the bioimaging field. Herein, we report a D–A–D-type
organic NIR-II fluorophore with typical AIE character (αAIE > 4) through careful manipulation of the electron donor
and acceptor. The tumor-associated macrophage (TAM)-derived exosomes
with nanometer size were used as templates to encapsulate the NIR-II
AIEgens (oBBT-DPNA) in a well-defined structure (named
as AIE@Exo). The AIE@Exo displayed a superb aggregation-intensified
NIR-II fluorescence with a maximum emission peak at 1052 nm as well
as a calculated fluorescence quantum yield (QY) of 3.1%. Moreover,
the in vivo application of AIE@Exo in efficient NIR-II
fluorescence imaging of whole-body vessels and tumor was successfully
demonstrated in living mice. Overall, the nanometer-sized biomimetic
nanoparticles represent successful NIR-II AIE nanoparticles for biomedical
imaging.
The
short lifespan of reactive oxygen species (ROS) and hypoxia
nature of solid tumor severely impede the therapeutic efficacy of
photodynamic therapy (PDT). To overcome this challenge, the light-triggered
PDT/carbon monoxide (CO) gas therapy synergistic systems have received
considerable attention. However, the development of single organic
material-based multifunctional nanoplatforms for NIR-II fluorescence
imaging (NIR-II FI) and synergistic PDT/CO gas therapy remains a challenge.
Herein, a multifunctional NIR-II FI/PDT/CO gas therapy conjugated
polymer brush (PBF-g-CO/PEG) was established by covalent conjugation
of CO donors (CORM-401) onto a water-soluble polyamidoamine dendrimer-modified
NIR-II fluorophore (PBF-AM3). The electron-rich polyamidoamine dendrimer-modified
PBF-AM3 could be irradiated with 660 nm light to efficiently produce
ROS and trigger CO release from CORM-401 inducing cancer cell apoptosis.
Importantly, under the guidance of NIR-II FI, the PBF-g-CO/PEG polymer
demonstrates superior in vivo anticancer efficacy
by the combination of photodynamic and CO gas therapy. The remarkable
anticancer efficacy and admirable biocompatibility endow PBF-g-CO/PEG
with great potential for precision cancer therapy.
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