8 research outputs found
Photosensitizer Decorated Red Blood Cells as an Ultrasensitive Light-Responsive Drug Delivery System
Red blood cells (RBCs) have been
widely explored as a natural drug delivery system (DDS) owing to their
inherent biocompatibility and large internal cavities to load various
types of functional molecules. Herein, we uncover that a photosensitizer,
chlorin e6 (Ce6), could be decorated into the membrane of RBCs upon
simple mixing, without affecting the membrane integrity and stability
in dark. Upon light irradiation with a rather low power density, the
singlet oxygen generated by Ce6 would lead to rather efficient disruption
of RBC membrane. With doxorubicin (DOX), a typical chemotherapy drug,
as the model, we engineer a unique type of light-responsive RBC-based
DDS by decorating Ce6 on the cell membrane and loading DOX inside
cells. The light triggered cell membrane breakdown would thus trigger
instant release of DOX, enabling light-controlled chemotherapy with
great specificity. Beyond that our RBC system could also be utilized
for loading of larger biomolecules such as enzymes, whose release
as well as catalytic function is also controlled by light. Our work
thus presents a unique type of biocompatible cell-based DDS that can
be precisely controlled by mild external stimuli, promising not only
for cancer therapy but also for other potential applications in biotechnologies
Theranostic Liposomes with Hypoxia-Activated Prodrug to Effectively Destruct Hypoxic Tumors Post-Photodynamic Therapy
Photodynamic
therapy (PDT), a noninvasive cancer therapeutic method
triggered by light, would lead to severe tumor hypoxia after treatment.
Utilizing a hypoxia-activated prodrug, AQ4N, which only shows toxicity
to cancer cells under hypoxic environment, herein, a multipurpose
liposome is prepared by encapsulating hydrophilic AQ4N and hydrophobic
hexadecylamine conjugated chlorin e6 (<i>h</i>Ce6), a photosensitizer,
into its aqueous cavity and hydrophobic bilayer, respectively. After
chelating a <sup>64</sup>Cu isotope with Ce6, the obtained AQ4N-<sup>64</sup>Cu-<i>h</i>Ce6-liposome is demonstrated to be an
effective imaging probe for <i>in vivo</i> positron emission
tomography, which together with <i>in vivo</i> fluorescence
and photoacoustic imaging uncovers efficient passive homing of those
liposomes after intravenous injection. After being irradiated with
the 660 nm light-emitting diode light, the tumor bearing mice with
injection of AQ4N-<i>h</i>Ce6-liposome show severe tumor
hypoxia, which in turn would trigger activation of AQ4N, and finally
contributes to remarkably improved cancer treatment outcomes <i>via</i> sequential PDT and hypoxia-activated chemotherapy. This
work highlights a liposome-based theranostic nanomedicine that could
utilize tumor hypoxia, a side effect of PDT, to trigger chemotherapy,
resulting in greatly improved efficacy compared to conventional cancer
PDT
Graphene-Based Nanocomposite As an Effective, Multifunctional, and Recyclable Antibacterial Agent
The
development of new antibacterial agents that are highly effective
are of great interest. Herein, we present a recyclable and synergistic
nanocomposite by growing both iron oxide nanoparticles (IONPs) and
silver nanoparticles (AgNPs) on the surface of graphene oxide (GO),
obtaining GO-IONP-Ag nanocomposite as a novel multifunctional antibacterial
material. Compared with AgNPs, which have been widely used as antibacterial
agents, our GO-IONP-Ag shows much higher antibacterial efficiency
toward both Gram-negative bacteria <i>Escherichia coli</i> (<i>E. coli</i>) and Gram-positive bacteria <i>Staphylococcus
aureus</i> (<i>S. aureus</i>). Taking the advantage
of its strong near-infrared (NIR) absorbance, photothermal treatment
is also conducted with GO-IONP-Ag, achieving a remarkable synergistic
antibacterial effect to inhibit <i>S. aureus</i> at a rather
low concentration of this agent. Moreover, with magnetic IONPs existing
in the composite, we can easily recycle GO-IONP-Ag by magnetic separation,
allowing its repeated use. Given the above advantages as well as its
easy preparation and cheap cost, GO-IONP-Ag developed in this work
may find potential applications as a useful antibacterial agent in
the areas of healthcare and environmental engineering
Near-Infrared-Triggered Photodynamic Therapy with Multitasking Upconversion Nanoparticles in Combination with Checkpoint Blockade for Immunotherapy of Colorectal Cancer
While
immunotherapy has become a highly promising paradigm for
cancer treatment in recent years, it has long been recognized that
photodynamic therapy (PDT) has the ability to trigger antitumor immune
responses. However, conventional PDT triggered by visible light has
limited penetration depth, and its generated immune responses may
not be robust enough to eliminate tumors. Herein, upconversion nanoparticles
(UCNPs) are simultaneously loaded with chlorin e6 (Ce6), a photosensitizer,
and imiquimod (R837), a Toll-like-receptor-7 agonist. The obtained
multitasking UCNP-Ce6-R837 nanoparticles under near-infrared (NIR)
irradiation with enhanced tissue penetration depth would enable effective
photodynamic destruction of tumors to generate a pool of tumor-associated
antigens, which in the presence of those R837-containing nanoparticles
as the adjuvant are able to promote strong antitumor immune responses.
More significantly, PDT with UCNP-Ce6-R837 in combination with the
cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) checkpoint blockade
not only shows excellent efficacy in eliminating tumors exposed to
the NIR laser but also results in strong antitumor immunities to inhibit
the growth of distant tumors left behind after PDT treatment. Furthermore,
such a cancer immunotherapy strategy has a long-term immune memory
function to protect treated mice from tumor cell rechallenge. This
work presents an immune-stimulating UCNP-based PDT strategy in combination
with CTLA-4 checkpoint blockade to effectively destroy primary tumors
under light exposure, inhibit distant tumors that can hardly be reached
by light, and prevent tumor reoccurrence <i>via</i> the
immune memory effect
Nanoscale Metal–Organic Particles with Rapid Clearance for Magnetic Resonance Imaging-Guided Photothermal Therapy
Nanoscale metal–organic particles
(NMOPs) are constructed
from metal ions and organic bridging ligands <i>via</i> the
self-assembly process. Herein, we fabricate NMOPs composed of Mn<sup>2+</sup> and a near-infrared (NIR) dye, IR825, obtaining Mn-IR825
NMOPs, which are then coated with a shell of polydopamine (PDA) and
further functionalized with polyethylene glycol (PEG). While Mn<sup>2+</sup> in such Mn-IR825@PDA–PEG NMOPs offers strong contrast
in <i>T</i><sub>1</sub>-weighted magnetic resonance (MR)
imaging, IR825 with strong NIR optical absorbance shows efficient
photothermal conversion with great photostability in the NMOP structure.
Upon intravenous injection, Mn-IR825@PDA–PEG shows efficient
tumor homing together with rapid renal excretion behaviors, as revealed
by MR imaging and confirmed by biodistribution measurement. Notably,
when irradiated with an 808 nm laser, tumors on mice with Mn-IR825@PDA–PEG
injection are completely eliminated without recurrence within 60 days,
demonstrating the high efficacy of photothermal therapy with this
agent. This study demonstrates the use of NMOPs as a potential photothermal
agent, which features excellent tumor-targeted imaging and therapeutic
functions, together with rapid renal excretion behavior, the latter
of which would be particularly important for future clinical translation
of nanomedicine
Smart Nanoreactors for pH-Responsive Tumor Homing, Mitochondria-Targeting, and Enhanced Photodynamic-Immunotherapy of Cancer
Photodynamic
therapy (PDT) is an oxygen-dependent light-triggered
noninvasive therapeutic method showing many promising aspects in cancer
treatment. For effective PDT, nanoscale carriers are often needed
to realize tumor-targeted delivery of photosensitizers, which ideally
should further target specific cell organelles that are most vulnerable
to reactive oxygen species (ROS). Second, as oxygen is critical for
PDT-induced cancer destruction, overcoming hypoxia existing in the
majority of solid tumors is important for optimizing PDT efficacy.
Furthermore, as PDT is a localized treatment method, achieving systemic
antitumor therapeutic outcomes with PDT would have tremendous clinical
values. Aiming at addressing the above challenges, we design a unique
type of enzyme-encapsulated, photosensitizer-loaded hollow silica
nanoparticles with rationally designed surface engineering as smart
nanoreactors. Such nanoparticles with pH responsive surface coating
show enhanced retention responding to the acidic tumor microenvironment
and are able to further target mitochondria, the cellular organelle
most sensitive to ROS. Meanwhile, decomposition of tumor endogenous
H<sub>2</sub>O<sub>2</sub> triggered by those nanoreactors would lead
to greatly relieved tumor hypoxia, further favoring in vivo PDT. Moreover,
by combining our nanoparticle-based PDT with check-point-blockade
therapy, systemic antitumor immune responses could be achieved to
kill nonirradiated tumors 1–2 cm away, promising for metastasis
inhibition
Renal-Clearable Ultrasmall Coordination Polymer Nanodots for Chelator-Free <sup>64</sup>Cu-Labeling and Imaging-Guided Enhanced Radiotherapy of Cancer
Developing
tumor-homing nanoparticles with integrated diagnostic
and therapeutic functions, and meanwhile could be rapidly excreted
from the body, would be of great interest to realize imaging-guided
precision treatment of cancer. In this study, an ultrasmall coordination
polymer nanodot (CPN) based on the coordination between tungsten ions
(W<sup>VI</sup>) and gallic acid (W-GA) was developed <i>via</i> a simple method. After polyethylene glycol (PEG) modification, PEGylated
W-GA (W-GA-PEG) CPNs with an ultrasmall hydrodynamic diameter of 5
nm were rather stable in various physiological solutions. Without
the need of chelator molecules, W-GA-PEG CPNs could be efficiently
labeled with radioisotope <sup>64</sup>Cu<sup>2+</sup>, enabling positron
emission tomography (PET) imaging, which reveals efficient tumor accumulation
and rapid renal clearance of W-GA-PEG CPNs upon intravenous injection.
Utilizing the radio-sensitizing function of tungsten with strong X-ray
absorption, such W-GA-PEG CPNs were able to greatly enhance the efficacy
of cancer radiotherapy in inhibiting the tumor growth. With fast clearance
and little long-term body retention, those W-GA-PEG CPNs exhibited
no appreciable <i>in vivo</i> toxicity. This study presents
a type of CPNs with excellent imaging and therapeutic abilities as
well as rapid renal clearance behavior, promising for further clinic
translation
Synthesis of Hollow Biomineralized CaCO<sub>3</sub>–Polydopamine Nanoparticles for Multimodal Imaging-Guided Cancer Photodynamic Therapy with Reduced Skin Photosensitivity
The
development of activatable nanoplatforms to simultaneously
improve diagnostic and therapeutic performances while reducing side
effects is highly attractive for precision cancer medicine. Herein,
we develop a one-pot, dopamine-mediated biomineralization method using
a gas diffusion procedure to prepare calcium carbonate-polydopamine
(CaCO<sub>3</sub>–PDA) composite hollow nanoparticles as a
multifunctional theranostic nanoplatform. Because of the high sensitivity
of such nanoparticles to pH, with rapid degradation under a slightly
acidic environment, the photoactivity of the loaded photosensitizer,
i.e., chlorin e6 (Ce6), which is quenched by PDA, is therefore increased
within the tumor under reduced pH, showing recovered fluorescence
and enhanced singlet oxygen generation. In addition, due to the strong
affinity between metal ions and PDA, our nanoparticles can bind with
various types of metal ions, conferring them with multimodal imaging
capability. By utilizing pH-responsive multifunctional nanocarriers,
effective in vivo antitumor photodynamic therapy (PDT) can be realized
under the precise guidance of multimodal imaging. Interestingly, at
normal physiological pH, our nanoparticles are quenched and show much
lower phototoxicity to normal tissues, thus effectively reducing skin
damage during PDT. Therefore, our work presents a unique type of biomineralized
theranostic nanoparticles with inherent biocompatibility, multimodal
imaging functionality, high antitumor PDT efficacy, and reduced skin
phototoxicity