Tumor microenvironment-responsive delivery nanosystems reverse immunosuppression for enhanced CO gas/immunotherapy

Spatially Confined Nanoreactors Designed for Biological Applications

The applications of nanoreactors in biology are becoming increasingly significant and prominent. Specifically, nanoreactors with spatially confined, due to their exquisite design that effectively limits the spatial range of biomolecules, attracted widespread attention. The main advantage of this structure is designed to improve reaction selectivity and efficiency by accumulating reactants and catalysts within the chambers, thus increasing the frequency of collisions between reactants. Herein, the recent progress in the synthesis of spatially confined nanoreactors and their biological applications is summarized, covering various kinds of nanoreactors, including porous inorganic materials, porous crystalline materials with organic components and self-assembled polymers to construct nanoreactors. These design principles underscore how precise reaction control could be achieved by adjusting the structure and composition of the nanoreactors to create spatial confined. Furthermore, various applications of spatially confined nanoreactors are demonstrated in the biological fields, such as biocatalysis, molecular detection, drug delivery, and cancer therapy. These applications showcase the potential prospects of spatially confined nanoreactors, offering robust guidance for future research and innovation.

A redox homeostasis disruptor based on a biodegradable nanoplatform for ultrasound (US) imaging-guided high-performance ferroptosis therapy of tumors

The synergistic disruption of intracellular redox homeostasis through the combination of ferroptosis/gas therapy shows promise in enhancing the antitumor efficacy. However, the development of an optimal delivery system encounters significant challenges, including effective storage, precise delivery, and controlled release of therapeutic gas. In this study, we propose the utilization of a redox homeostasis disruptor that is selectively activated by the tumor microenvironment (TME), in conjunction with our newly developed nanoplatforms (MC@HMOS@Au@RGD), for highly efficient ferroptosis therapy of tumors. The TME-triggered degradation of HMOS initiates the release of MC and AuNPs from the MC@HMOS@Au@RGD nanoplatform. The released MC subsequently reacts with endogenous hydrogen peroxide (H2O2) and H+ to enable the on-demand release of CO gas, leading to mitochondrial damage. Simultaneously, the released AuNPs exhibit GOx-like activity, catalyzing glucose to generate gluconic acid and H2O2. This process not only promotes the decomposition of MnCO to enhance CO production but also enhances the Fenton-like reaction between Mn2+ and H2O2, generating ROS through the modulation of the H+ and H2O2-enriched TME. Moreover, the generation of CO bubbles enables the monitoring of the ferroptosis treatment process through ultrasound (US) imaging. The efficacy of our prepared MC@HMOS@Au@RGD disruptors in ferroptosis therapy is validated through both in vitro and in vivo experiments.

Selective Manipulation of the Mitochondria Oxidative Stress in Different Cells Using Intelligent Mesoporous Silica Nanoparticles to Activate On-Demand Immunotherapy for Cancer Treatment

Herein, the vitamin K2 (VK2)/maleimide (MA) coloaded mesoporous silica nanoparticles (MSNs), functional molecules including folic acid (FA)/triphenylphosphine (TPP)/tetrapotassium hexacyanoferrate trihydrate (THT), as well as CaCO3 are explored to fabricate a core-shell-corona nanoparticle (VMMFTTC) for on-demand anti-tumor immunotherapy. After application, the tumor-specific acidic environment first decomposed CaCO3 corona, which significantly levitates the pH value of tumor tissue to convert M2 type macrophage to the antitumor M1 type. The resulting VMMFTT would then internalize in both tumor cells and macrophages via FA-assisted endocytosis and free endocytosis, respectively. These distinct processes generate different amount of VMMFTT in above two cells followed by 1) TPP-induced accumulation in the mitochondria, 2) THT-mediated effective capture of various signal ions to cut off signal transmission and further inhibit glutathione (GSH) generation, 3) ions catalyzed reactive oxygen species (ROS) production through Fenton reaction, 4) sustained release of VK2 and MA to further enhance the ROS production and GSH depletion, which caused significant apoptosis of tumor cells and additional M2-to-M1 macrophage polarization via different processes of oxidative stress. Moreover, the primary tumor apoptosis further matures surrounding immature dendritic cells and activates T cells to continuously promote the antitumor immunotherapy.

Probing the Impact of Surface Functionalization Module on the Performance of Mitoxantrone Prodrug Nanoassemblies: Improving the Effectiveness and Safety

Prodrug nanoassemblies are emerging as a novel drug delivery system for chemotherapy, comprising four fundamental modules: a drug module, a modification module, a response module, and a surface functionalization module. Among these modules, surface functionalization is an essential process to enhance the biocompatibility and stability of the nanoassemblies. Here, we selected mitoxantrone (MTO) as the drug module and DSPE-PEG2K as surface functionalization module to develop MTO prodrug nanoassemblies. We systematically evaluated the effect of surface functionalization module ratios (10%, 20%, 40%, and 60% of prodrug, WDSPE-mPEG2000/Wprodrug) on the prodrug nanoassemblies. The results indicated that 40% NPs significantly improved the self-assembly stability and cellular uptake of prodrug nanoassemblies. Compared with MTO solution, 40% NPs showed better tumor specificity and pharmacokinetics, resulting in potent antitumor activity with a good safety profile. These findings highlighted the pivotal role of the surface functionalization module in regulating the performance of mitoxantrone prodrug nanoassemblies for cancer treatment.

Platinum Prodrug Nanoparticles with COX-2 Inhibition Amplify Pyroptosis for Enhanced Chemotherapy and Immune Activation of Pancreatic Cancer

Pyroptosis, an emerging mechanism of programmed cell death, holds great potential to trigger a robust antitumor immune response. Platinum-based chemotherapeutic agents can induce pyroptosis via caspase-3 activation. However, these agents also enhance cyclooxygenase-2 (COX-2) expression in tumor tissues, leading to drug resistance and immune evasion in pancreatic cancer and significantly limiting the effectiveness of chemotherapy-induced pyroptosis. Here, an amphiphilic polymer (denoted as PHDT-Pt-In) containing both indomethacin (In, a COX-2 inhibitor) and platinum(IV) prodrug (Pt(IV)) is developed, which is responsive to glutathione (GSH). This polymer self-assemble into nanoparticles (denoted as Pt-In NP) that can disintegrate in cancer cells due to the GSH responsiveness, releasing In to inhibit the COX-2 expression, hence overcoming the chemoresistance and amplifying cisplatin-induced pyroptosis. In a pancreatic cancer mouse model, Pt-In NP significantly inhibit tumor growth and elicit both innate and adaptive immune responses. Moreover, when combined with anti-programmed death ligand (α-PD-L1) treatment, Pt-In NP demonstrate the ability to completely suppress metastatic tumors, transforming "cold tumors" into "hot tumors". Overall, the sustained release of Pt(IV) and In from Pt-In NP amplifies platinum-drug-induced pyroptosis to elicit long-term immune responses, hence presenting a generalizable strategy for pancreatic cancer.

Cathepsin B-Responsive Programmed Brain Targeted Delivery System for Chemo-Immunotherapy Combination Therapy of Glioblastoma

Tumor-associated macrophages (TAMs) are closely related to the progression of glioblastoma multiform (GBM) and its development of therapeutic resistance to conventional chemotherapy. TAM-targeted therapy combined with conventional chemotherapy has emerged as a promising strategy to combat GBM. However, the presence of the blood-brain barrier (BBB) severely limits the therapeutic efficacy. Meanwhile, the lack of ability to distinguish different targeted cells also poses a challenge for precise therapy. Herein, we propose a cathepsin B (CTSB)-responsive programmed brain-targeted delivery system (D&R-HM-MCA) for simultaneous TAM-targeted and GBM-targeted delivery. D&R-HM-MCA could cross the BBB via low density lipoprotein receptor-associated protein 1 (LRP1)-mediated transcytosis. Upon reaching the GBM site, the outer angiopep-2 modification could be detached from D&R-HM-MCA via cleavage of the CTSB-responsive peptide, which could circumvent abluminal LRP1-mediated efflux. The exposed p-aminophenyl-α-d-mannopyranoside (MAN) modification could further recognize glucose transporter-1 (GLUT1) on GBM and macrophage mannose receptor (MMR) on TAMs. D&R-HM-MCA could achieve chemotherapeutic killing of GBM and simultaneously induce TAM polarization from anti-inflammatory M2 phenotype to pro-inflammatory M1 phenotype, thus resensitizing the chemotherapeutic response and improving anti-GBM immune response. This CTSB-responsive brain-targeted delivery system not only can improve brain delivery efficiency, but also can enable the combination of chemo-immunotherapy against GBM. The effectiveness of this strategy may provide thinking for designing more functional brain-targeted delivery systems and more effective therapeutic regimens.

Recent theranostic applications of hydrogen peroxide-responsive nanomaterials for multiple diseases

It is well established that hydrogen peroxide (H2O2) is associated with the initiation and progression of many diseases. With the rapid development of nanotechnology, the diagnosis and treatment of those diseases could be realized through a variety of H2O2-responsive nanomaterials. In order to broaden the application prospects of H2O2-responsive nanomaterials and promote their development, understanding and summarizing the design and application fields of such materials has attracted much attention. This review provides a comprehensive summary of the types of H2O2-responsive nanomaterials including organic, inorganic and organic-inorganic hybrids in recent years, and focused on their specific design and applications. Based on the type of disease, such as tumors, bacteria, dental diseases, inflammation, cardiovascular diseases, bone injury and so on, key examples for above disease imaging diagnosis and therapy strategies are introduced. In addition, current challenges and the outlook of H2O2-responsive nanomaterials are also discussed. This review aims to stimulate the potential of H2O2-responsive nanomaterials and provide new application ideas for various functional nanomaterials related to H2O2.