Repolarizing tumor-associated macrophages by layered double hydroxide-based deacidification agent for tumor chemodynamic therapy and immunotherapy.

Tumor-associated macrophages (TAMs)-mediated immunotherapy has attracted extensive attention in tumor elimination. However, the acidic tumor microenvironment (TME) severely limits the phenotype of TAMs to pro-tumoral M2 state, suppressing immune response efficacy against tumors. Herein, novel poly(acrylic acid) (PAA)-coated, doxorubicin (DOX)-loaded layered double hydroxide (LDH) nanosheets (NSs) were developed as deacidification agent to repolarize TAMs from pro-tumoral M2 to anti-tumoral M1 phenotype for tumor elimination through combined chemodynamic therapy and immunotherapy. When located in tumor regions, LDH-PAA@DOX NSs display good deacidification capacity to neutralize acidic TME, achieving the repolarization of TAMs to M1 phenotype and further activating CD8+ T cells. During the deacidification process, these NSs are acid-responsive and degrade to release Fe3+ and DOX. The former can be reduced to Fe2+ by intracellular glutathione, meanwhile disrupting the antioxidant defense system of tumor cells. The latter can damage tumor cells directly and further stimulate the production of hydrogen peroxide, providing abundant substrate for the Fenton reaction. Toxic hydroxyl radical is excessively produced through Fe2+-mediated Fenton reaction to cause intratumoral oxidative stress. In vivo data revealed that significant tumor elimination can be achieved under LDH-PAA@DOX treatment. This work not only provides a promising paradigm for neutralizing acidic TME using deacidification agent but also highlights the effectiveness of combined chemodynamic therapy and immunotherapy in tumor treatment.

Janus-like Bx C/C Quantum Sheets with Z-Scheme Mechanism Strengthen Tumor Photothermal-Immunotherapy in NIR-II Biowindow.

Carbon dots (CDs) are one of the most popular photothermal agents (PTAs) as a noninvasive strategy for tumor treatment. However, because of the inherent dominant fluorescent emission, the CDs-based PTAs hardly achieve a single photothermal conversion, which causes low photothermal conversion efficiency and poor photothermal performance. In this regard, finding a new CDs-based material system to greatly restrain its fluorescence to enhance its photothermal conversion efficiency is highly required, however, it is still a grand challenge. Herein, a kind of Z-scheme CDs-based PTAs consisting of 2D ultrathin nonmetallic Bx C/C Janus quantum sheets (Bx C/C JQSs) is reported to greatly enhance the photothermal conversion efficiency. It is demonstrated that the heterogeneous growth of Z-scheme Bx C/C JQSs enables the NIR-driven quick injection of hot electrons from C into the conjugated Bx C, realizing a single conversion of light to heat, and resulting in a high photothermal conversion of 60.0% in NIR-II. Furthermore, these new Z-scheme Bx C/C-polyethylene glycol JQSs display outstanding biocompatibility and show effective tumor elimination outcome both in vitro and in vivo through the synergistic photothermal-immunotherapy in the NIR-II biowindow with undetectable harm to normal tissues.

Integration of cascade delivery and tumor hypoxia modulating capacities in core-releasable satellite nanovehicles to enhance tumor chemotherapy.

Drug nanovehicles owning tumor microenvironment responsive and modulating capacities are highly demanding for effective tumor chemotherapy but still lack of exploration. Here, a kind of core-releasable satellite nanovehicles was rational constructed, which is composed of polydopamine (PDA) cores as photothermal agents and the carrier for small satellite nanoparticles (NPs) and drugs, G5Au NPs as the drug-loading satellites for deep tumor drug delivery and as catalase-like agents for relieving tumor hypoxia, doxorubicin (DOX) as the model chemotherapeutic drug loaded by both PDA and G5Au NPs, and polyethylene glycol (PEG) shells to improve biosafety. The developed drug-loaded nanovehicles (denoted as PDA-G5Au-PEG@DOX) can release G5Au satellites and DOX in stimuli-responsive manners. Thorough drug delivery in solid tumor can be realized via transporting DOX to the near-by area of and remote area from blood vessels by PDA and G5Au, respectively. Monitored by photoacoustic imaging and near-infrared fluorescence imaging, these PDA-G5Au-PEG@DOX NPs could accumulate in 4T1 tumor effectively. Under this guidance, significant tumor growth suppression could be achieved by the treatment of PDA-G5Au-PEG@DOX NPs plus laser without detectable side effects during the treatment period. The developed drug-loaded core-satellite nanovehicles with tumor microenvironment responsive/modulating capacities are of great potential in precise tumor treatments.

Construction of a Polypyrrole-Based Multifunctional Nanocomposite for Dual-Modal Imaging and Enhanced Synergistic Phototherapy against Cancer Cells.

Design and construction of multifunctional theranostic nanoplatforms are still desired for cancer-effective treatment. Herein, a kind of polypyrrole (PPy)-based multifunctional nanocomposite was designed and successfully constructed for dual-model imaging and enhanced synergistic phototherapy against cancer cells. Through graphene oxide (GO) sheet coating, PPy nanoparticles (NPs) were effectively combined with polyethylene glycol chains, Au NPs, and IR820 molecules. The obtained PGPAI NPs showed promising ability for photoacoustic/computed tomography imaging. Under near-infrared light irradiation, the PPy core and IR820 molecule effectively generated heat and reactive oxygen species (ROS), respectively. Furthermore, the loaded Au NPs owning catalase-like activity produced oxygen by decomposing H2O2 (up-regulated in tumor region), enhancing the oxygen-dependent photodynamic therapy efficacy. The formed PGPAI NPs were also proved to own desirable photothermal conversion efficiency, photothermal stability, colloidal stability, cytocompatibility, and cellular internalization behaviors. Furthermore, cell assay demonstrated that PGPAI NPs displayed enhanced synergistic phototherapy efficacy against cancer cells. These developed multifunctional nanoplatforms are promising for effective cancer theranostic applications.