Preparation of Dye Molecule-Intercalated MoO3 Organic/Inorganic Superlattice Nanoparticles for Fluorescence Imaging-Guided Catalytic Therapy

Engineered microalgae for photo-sonodynamic synergistic therapy in breast cancer treatment

Dynamic therapies such as photodynamic therapy (PDT) and sonodynamic therapy (SDT) have potential in cancer treatment. Microalgae have attracted increasing attention because of their high active mobility, flexibility in terms of functionality, and good biocompatibility. In this study, surface-engineered microalgae Chlorella vulgaris (Chl) modified with metal‒organic framework (MOF) nanoparticles (denoted Chl-MOF) are successfully developed for synergistic photo-sonodynamic therapy and immunotherapy. The resulting Chl-MOF can be used as an oxygenator for O2 generation through Chl-mediated photosynthesis, alleviating tumor hypoxia. Furthermore, Chl-MOF produces reactive oxygen species (ROS) during laser and ultrasound (US) irradiation, further augmenting the photo-sonodynamic effects and enhancing tumor cell apoptosis. Owing to the high mobility of Chl, cellular uptake efficiency and accumulation in deep tumor sites are 5.2-fold and 3.3-fold higher, respectively, for Chl-MOF than for the MOF. Owing to the immunomodulatory effects of Chl, Chl-MOF can increase natural killer (NK) cell cytotoxic activity, increase dendritic cell (DC) antigen-presenting ability, reverse the establishment of an immunosuppressive tumor microenvironment (TME), and induce a relatively strong antitumor immune response. Chl-MOF can effectively reduce breast cancer size by 88.8 % in vitro and in vivo via synergistic photo-sonodynamic therapy and immunotherapy. These intriguing properties of the combination of Chl and MOF provide promising platform for cancer theranostic applications. STATEMENT OF SIGNIFICANCE: : • Chl acts as an O2 generator for alleviating hypoxia in tumors. • The high mobility of Chl resulted in 3.3-folds higher tumor accumulation. • The Chl-MOF can induce synergistic photo-sonodynamic effects and a relatively strong antitumor immune response. • Chl-MOF effectively reduce breast cancer size by 88.8 % via synergistic therapies.

Coupling Probiotics with CaO2 Nanoparticle-Loaded CoFeCe-LDH Nanosheets to Remodel the Tumor Microenvironment for Precise Chemodynamic Therapy

Chemodynamic therapy (CDT) has become an emerging cancer treatment strategy with advantages of tumor-specificity, high selectivity, and low systemic toxicity. However, it usually suffers from low therapeutic efficacy. This is caused by low hydroxyl radical (·OH) yield arising because of the relatively high pH, overexpressed glutathione, and low H2O2 concentration in the tumor microenvironment (TME). Herein, a probiotic metabolism-initiated pH reduction and H2O2 supply-enhanced CDT strategy is reported to eradicate tumors by generating ·OH, in which Lactobacillus acidophilus is coupled with CoFeCe-layered double hydroxide nanosheets loaded with CaO2 nanoparticles (NPs) as a chemodynamic platform for high-efficiency CDT (CaO2/LDH@L. acidophilus). Owing to the hypoxia tropism of L. acidophilus, CaO2/LDH@L. acidophilus exhibits increased accumulation at tumor sites compared with the CaO2/LDH. The CaO2 NPs loaded on CoFeCe-LDH nanosheets are decomposed into H2O2 in the TME. L. acidophilus metabolite-induced pH reduction (<5.5) and CaO2-mediated in situ H2O2 generation synergistically boost ·OH generation activity of the CoFeCe-LDH nanosheets, effectively damaging cancer cells and ablating tumors with a tumor inhibition rate of 96.4%, 2.32-fold higher than that of CaO2/LDH. This work demonstrates that probiotics can function as a tumor-targeting platform to remodel the TME and amplify ROS generation for highly efficient and precise CDT.

Discrete Macrocyclic Polymer Hosts-Induced Cascade Luminescence Enhancement and Application in Bioimaging

The integration of polymers, supramolecular macrocycles and aggregation-induced emission (AIE) molecules provides numerous possibilities for constructing various functional supramolecular systems. Herein, we constructed supramolecular assembled systems based on discrete macrocyclic polymer hosts via the cooperation of hydra-headed macrocycles containing two or three pillar[5]arene units (defined as P2, P3), the block polymer F127 and AIE molecules (alkyl-cyano modified tetraphenylethene, alkyl-triazole-cyano modified 9,10-distyrylanthracene, defined as TPE-(CN)4 and DSA-(TACN)2). Compared with the binary assembly between hydra-headed hosts or F127 and AIE molecules, cascaded supramolecular assembly-induced emission enhancement (SAIEE) in aqueous solution was achieved in discrete macrocyclic polymer-based supramolecular assembled systems. Considering the cascaded SAIEE performance, we have successfully applied discrete macrocyclic polymer-based supramolecular assembled systems to bioimaging and constructed an artificial light-harvesting system (LHs) to explore more potential applications. The supramolecular assembly form of discrete macrocyclic polymers hosts and AIE molecules proposed in this work provides new inspiration for the construction and application of high-performance supramolecular luminescent systems.

Proton nanomodulators for enhanced Mn2+-mediated chemodynamic therapy of tumors via HCO3- regulation

BACKGROUND

Mn2+-mediated chemodynamic therapy (CDT) has been emerged as a promising cancer therapeutic modality that relies heavily on HCO3- level in the system. Although the physiological buffers (H2CO3/HCO3-) provide certain amounts of HCO3-, the acidity of the tumor microenvironment (TME) would seriously affect the HCO3- ionic equilibrium (H2CO3 ⇌ H+ + HCO3-). As a result, HCO3- level in the tumor region is actually insufficient to support effective Mn2+-mediated CDT.

RESULTS

In this study, a robust nanomodulator MnFe2O4@ZIF-8 (PrSMZ) with the capability of in situ self-regulation HCO3- is presented to enhance therapeutic efficacy of Mn2+-mediated CDT. Under an acidic tumor microenvironment, PrSMZ could act as a proton sponge to shift the HCO3- ionic equilibrium to the positive direction, significantly boosting the generation of the HCO3-. Most importantly, such HCO3- supply capacity of PrSMZ could be finely modulated by its ZIF-8 shell thickness, resulting in a 1000-fold increase in reactive oxygen species (ROS) generation. Enhanced ROS-dependent CDT efficacy is further amplified by a glutathione (GSH)-depletion ability and the photothermal effect inherited from the inner core MnFe2O4 of PrSMZ to exert the remarkable antitumor effect on mouse models.

CONCLUSIONS

This work addresses the challenge of insufficient HCO3- in the TME for Mn2+-mediated Fenton catalysts and could provide a promising strategy for designing high-performance Mn2+-mediated CDT agents to treat cancer effectively.

Bifunctional Bismuth-Based Layered Double Hydroxide Sonosensitizer for Magnetic Resonance Imaging-Guided Sonodynamic Cancer Therapy

Novel inorganic sonosensitizers with excellent reactive oxygen species (ROS) generation activity and multifunctionality are appealing in sonodynamic therapy (SDT). Herein, amorphous bismuth (Bi)-doped CoFe-layered double hydroxide (a-CoBiFe-LDH) nanosheets are proposed via crystalline-to-amorphous phase transformation strategy as a new type of bifunctional sonosensitizer, which allows ultrasound (US) to trigger ROS generation for magnetic resonance imaging (MRI)-guided SDT. Importantly, a-CoBiFe-LDH nanosheets exhibit much higher ROS generation activity (≈6.9 times) than that of traditional TiO2 sonosensitizer under US irradiation, which can be attributed to the acid etching-induced narrow band gap, high electron (e-)/hole (h+) separation efficiency and inhibited e-/h+ recombination. In addition, the paramagnetic properties of Fe ion endow a-CoBiFe-LDH with excellent MRI contrast ability, making it a promising contrast agent for T2-weighted MRI. After modification with polyethylene glycol, a-CoBiFe-LDH nanosheets can function as a high-efficiency sonosensitizer to activate p53, MAPK, oxidative phosphorylation, and apoptosis-related signaling pathways, ultimately inducing cell apoptosis in vitro and tumor ablation in vivo under US irradiation, which shows great potential for clinical cancer treatment.

Tumor microenvironment responsive chitosan-coated W-doped MoOx biodegradable composite nanomaterials for photothermal/chemodynamic synergistic therapy

Chemodynamic therapy (CDT), an approach that eradicates tumor cells through the catalysis of hydrogen peroxide (H2O2) into highly toxic hydroxyl radicals (·OH), possesses distinct advantages in tumor specificity and minimal side effects. However, CDT's therapeutic efficacy is currently hampered by the low production efficiency of ·OH. To address this limitation, this study introduces a water-soluble chitosan-coated W-doped MoOx (WMoOx/CS) designed for the combined application of photothermal therapy (PTT) combined with CDT. The W-doped MoOx (WMoOx) was synthesized in one step by the hydrothermal method, and its surface was modified by water-soluble chitosan (carboxylated chitosan, CS) to enhance its biocompatibility. WMoOx boasts a high near-infrared photothermal conversion efficiency of 52.66 %, efficiently transducing near-infrared radiation into heat. Moreover, the Mo4+/Mo5+ and W5+ ions in WMoOx catalyze H2O2 to produce ·OH for CDT, and the Mo5+/Mo6+ and W6+ ions in WMoOx reduce intracellular glutathione levels and prevent the scavenging of ·OH by glutathione. Crucially, the combination of WMoOx/CS and near-infrared light irradiation demonstrates promising synergistic antitumor effects in both in vitro and in vivo models, highlighting its potential for the combined application of PTT and CDT.

Ultralow Loading Copper-Intercalated MoO3 Nanobelts with High Activity against Antibiotic-Resistant Bacteria

In recent years, the infection rate of antibiotic resistance has been increasing year by year, and the prevalence of super bacteria has posed a great threat to human health. Therefore, there is an urgent need to find new antibiotic alternatives with long-term inhibitory activity against a broad spectrum of bacteria and microorganisms in order to avoid the proliferation of more multidrug-resistant (MDR) bacteria. The presence of natural van der Waals (vdW) gaps in layered materials allows them to be easily inserted by different guest species, providing an attractive strategy for optimizing their physicochemical properties and applications. Here, we have successfully constructed a copper-intercalated α-MoO3 nanobelt based on nanoenzymes, which is antibacterial through the synergistic effect of multiple enzymes. Compared with α-MoO3, MoO3-x/Cu nanobelts with a copper loading capacity of 2.11% possess enhanced peroxidase (POD) catalytic activity and glutathione (GSH) depletion, indicating that copper intercalation significantly improves the catalytic performance of the nanoenzymes. The MoO3-x/Cu nanobelts are effective in inducing POD and oxidase (OXD) and catalase (CAT) activities in the presence of H2O2 and O2, which resulted in the generation of large amounts of reactive oxygen species (ROS), which were effective in bacterial killing. Interestingly, MoO3-x/Cu nanobelts can serve as glutathione oxidase (GSHOx)-like nanoenzymes, which can deplete GSH in bacteria and thus significantly improve the bactericidal effect. The multienzyme-catalyzed synergistic antimicrobial strategy shows excellent antimicrobial efficiency against β-lactamase-producing Escherichia coli (ESBL-E. coli) and methicillin-resistant Staphylococcus aureus (MRSA). MoO3-x/Cu exhibits excellent spectral bactericidal properties at very low concentrations (20 μg mL-1). Our work highlights the wide range of antibacterial and anti-infective biological applications of copper-intercalated MoO3-x/Cu nanobelt catalysts.

FRET-Based Host-Guest Supramolecular Probe for On-Site and Broad-Spectrum Detection of Pyrethroids in the Environment

The massive use of pyrethroid pesticides in agriculture has brought growing concerns about food safety due to their several harmful effects on human health, especially through the accumulation of the food chain. To date, most of the available analytical methods for pyrethroids still suffer from insufficient detection universality, complicated sample pretreatment, and detection processes, which severely limit their practical applications. Herein, a novel Förster resonance energy transfer (FRET)-assisted host-guest supramolecular nanoassembly is reported, for the first time, successfully realizing ratiometric fluorescent detection of pyrethroids in real samples through the indicator displacement assay (IDA) mechanism. This method is capable of detecting a broad spectrum of pyrethroids, including bifenthrin, cyfluthrin, cypermethrin, deltamethrin, etofenprox, fenvalerate, and permethrin, with ultrahigh detection sensitivity, great selectivity, high anti-interference ability, and, in particular, distinct emission color response from red to green. Such a large chromatic response makes this method available for fast and on-site detection of pyrethroids in real samples with the aid of several simple portable analytical apparatuses.

Anion-substitution interfacial engineering to construct C@MoS2 hierarchical nanocomposites for broadband electromagnetic wave absorption

Developing an effective strategy to regulate the interfacial properties of hierarchical structure is of great significance for preparation of high-performance electromagnetic wave absorption (EMA) materials. Ion-substitution can change intrinsic structure and properties of a materials, but its effect on the interfacial properties of hierarchical structure remained to be explored. Herein, we first constructed a C@MoS2 hierarchical structure via simple hydrothermal reaction, then used the ion-substitution strategy to replace the S atoms in MoS2 with O, F and Se, and finally obtained anion-substituted hierarchical structure (C@X-MoS2, X = O, F, Se). The results show that ion-substitution destroys the MoS2 crystal structure and realizes tunable dielectric properties of C@MoS2, which leads to further enhancement of overall interfacial polarization. After optimization, the absorption strength and width of C@O-MoS2 has been significantly improved. The minimum reflection loss (RLmin) reaches -62.17 dB, and the maximum effective absorption bandwidth (EABmax) is 7.0 GHz. The simulation results show the obtained absorbent can greatly reduce the radar cross section of target, indicating it has broad application potential. Therefore, this work provides a novel method for regulation of EMA performance of hierarchical structure and preparation of high-performance absorbents.

MXene-Based Functional Platforms for Tumor Therapy

Recently, 2D transition metal carbide, nitride, and carbonitrides (MXenes) materials stand out in the field of tumor therapy, particularly in the construction of functional platforms for optimal antitumor therapy due to their high specific surface area, tunable performance, strong absorption of near-infrared light as well as preferable surface plasmon resonance effect. In this review, the progress of MXene-mediated antitumor therapy is summarized after appropriate modifications or integration procedures. The enhanced antitumor treatments directly performed by MXenes, the significant improving effect of MXenes on different antitumor therapies, as well as the MXene-mediated imaging-guided antitumor strategies are discussed in detail. Moreover, the existing challenges and future development directions of MXenes in tumor therapy are presented.

Tumor-overexpressed enzyme responsive amphiphiles small molecular self-assembly nano-prodrug for the chemo-phototherapy against non-small-cell lung cancer

Rational design of self-assembly drug amphiphiles can provide a promising strategy for constructing nano-prodrug with high drug loading, smart stimuli-responsive drug release and high tumor selectivity. Herein, we report a small molecular amphiphile prodrug that can self-assemble into multifunctional nano-prodrug for enhanced anticancer effect by the combination of chemotherapy and phototherapy (PDT/PTT). In this prodrug, the simple insertion of quinone propionate into hydrophilic drug Irinotecan (Ir) generates suitable amphiphiles that endow a good self-assembly behavior of the prodrug and transform it into a stable and uniform nanoparticle. Interestingly, this excellent self-assembly behavior can load phototherapy agent ICG to form a multifunctional nano-prodrug, thereby enhancing the chemotherapeutic effect with PDT/PTT. Importantly, the quinone propionic acid moiety in the prodrug showed a high sensitivity to the overexpressed NAD(P)H:quinone oxidoreductase-1 (NQO1) in non-small cell lung cancer (NSCLC) cells, and this sensitivity enables the disassembly of nano-prodrug and efficient NQO1-responsive drug release. To further enhance the drug accumulation on tumor tissue and migrate the blood clearance, a biomimetic nano-prodrug has been successfully explored by coating hybrid membrane on the above nano-prodrug, which displays high selective inhibition of tumor growth and metastasis on NSCLC mice model. Our findings provide new insights into the rational design of tumor-overexpressed enzyme responsive nano-prodrug for cancer combinational therapy.

Preparation of 2D Polyaniline/MoO3- x Superlattice Nanosheets via Intercalation-Induced Morphological Transformation for Efficient Chemodynamic Therapy

Organic intercalation of layered nanomaterials is an attractive strategy to fabricate organic/inorganic superlattices for a wide range of promising applications. However, the synthesis of 2D organic/inorganic superlattice nanosheets remains a big challenge. Herein, the preparation of 2D polyaniline/MoO_{3- x} (PANI/MoO_{3- x} ) superlattice nanosheets via intercalation-induced morphological transformation from MoO₃  nanobelts, as efficient Fenton-like reagents for chemodynamic therapy (CDT), is reported. Micrometer-long MoO₃  nanobelts are co-intercalated with Na⁺ /H₂ O followed by the guest exchange with aniline monomer for in situ polymerization to obtain PANI/MoO_{3- x} nanosheets. Intriguingly, the PANI intercalation can induce the morphological transformation from long MoO₃  nanobelts to 2D PANI/MoO_{3- x} nanosheets along with the partial reduction of Mo⁶⁺ to Mo⁵⁺ , and generation of rich oxygen vacancies. More importantly, thanks to the PANI intercalation-induced activation, the PANI/MoO_{3- x} nanosheets exhibit excellent Fenton-like catalytic activity for generation of hydroxyl radical (·OH) by decomposing H₂ O₂  compared with the MoO₃  nanobelts. It is speculated that the good conductivity of PANI can facilitate electron transport during the Fenton-like reaction, thereby enhancing the efficiency of CDT. Thus, the polyvinylpyrrolidone-modified PANI/MoO_{3- x} nanosheets can function as Fenton-like reagents for highly efficient CDT to kill cancer cells and eradicate tumors.

Thermosensitive Hydrogel Loaded with Nickel-Copper Bimetallic Hollow Nanospheres with SOD and CAT Enzymatic-Like Activity Promotes Acute Wound Healing

Various injury defense and repair functions are performed by the skin. Free radicals secreted after injury cause oxidative stress and inflammatory responses, which make wound healing difficult. However, the current metal nanomaterials for wound repair do not have sufficient catalytic activity or complex material design and cannot properly fit wounds. Therefore, it is imperative to develop more effective therapeutic approaches. This study investigated the effect of Ni₄Cu₂ hollow nanospheres composited with F127 hydrogel on promoting wound healing by applying them to wounds. Ni₄Cu₂ hollow nanospheres exhibited a superior spatial structure, contained many catalytic sites, and could be synthesized in a simple manner. In vitro experiments showed that Ni₄Cu₂ hollow nanospheres had superoxide dismutase-like activity and promoted fibroblast migration, angiogenesis, and macrophage polarization. F127, which is a thermosensitive, nontoxic, phase-change and porous hydrogel material, has proven to be an effective choice for injectable and sprayable medical dressings. Ni₄Cu₂ hollow nanospheres were mixed with F127 hydrogel without significantly affecting its performance. In addition to adapting to the complex, irregular gaps of acute wounds, the mixture lengthened the nanozyme release time, which enhanced healing. Based on the animal experiments, the Ni₄Cu₂/F127 composite hydrogel effectively promoted wound healing, epithelial regeneration, and the formation of skin appendages such as hair follicles in mice. Furthermore, the Ni₄Cu₂/F127 composite hydrogel was nontoxic to animals and had high biological safety. The Ni₄Cu₂/F127 composite hydrogel has provided an innovative strategy to develop composite hydrogels for the treatment of acute skin wounds.

Ultrasmall zirconium carbide nanodots for synergistic photothermal-radiotherapy of glioma

Glioma is characterized by highly invasive, progressive, and lethal features. In addition, conventional treatments have been poorly effective in treating glioma. To overcome this challenge, synergistic therapies combining radiotherapy (RT) with photothermal therapy (PTT) have been proposed and extensively explored as a highly feasible cancer treatment strategy. Herein, ultrasmall zirconium carbide (ZrC) nanodots were successfully synthesized with high near-infrared absorption and strong photon attenuation for synergistic PTT-RT of glioma. ZrC-PVP nanodots with an average size of approximately 4.36 nm were prepared by the liquid exfoliation method and modified with the surfactant polyvinylpyrrolidone (PVP), with a satisfactory absorption and photothermal conversion efficiency (53.4%) in the near-infrared region. Furthermore, ZrC-PVP nanodots can also act as radiosensitizers to kill residual tumor cells after mild PTT due to their excellent photon attenuating ability, thus achieving a significant synergistic therapeutic effect by combining RT and PTT. Most importantly, both in vitro and in vivo experimental results further validate the high biosafety of ZrC-PVP NDs at the injected dose. This work systematically evaluates the feasibility of ZrC-PVP NDs for glioma treatment and provides evidence of the application of zirconium-based nanomaterials in photothermal radiotherapy.

Cold-catalytic antitumor immunity with pyroelectric black phosphorus nanosheets

Catalytic nanomedicine with the innate features of catalysts brings incomparable properties to biomedicine over traditional drugs. The temperature-dependent activity of catalysts provides catalytic nanomedicines with a facile strategy to control their therapeutic performance. Tuning catalytic nanomedicine by cold treatment (4-37 °C) is safe and desired for practical applications, but there is a lack of cold-catalytic platforms. Herein, with black phosphorus (BP) as a model pyroelectric nanocatalyst, we explored the potential of cold-catalysts for antitumor therapy. BP nanosheets with pyro-catalytic activity catalyze the generation of oxidative stress to activate antitumor immunity under cold treatment. Due to the cold-catalytic immunomodulation, immune memory was successfully achieved to prevent tumor metastasis and recurrence. Considering the safety and conductive depth (>10 mm) of cold in the body, pyroelectric nanocatalysts open up exciting opportunities for the development of cold-catalytic nanomedicine.