Nanozymes for regulation of reactive oxygen species and disease therapy

Sulfatase-mediated peroxidase-like activity: A chemiluminescence-based platform for high-throughput screening of natural inhibitors in cancer therapy

Sulfatase, traditionally known for its role in sulfate ester hydrolysis, has recently emerged as a potential player in tumor biology through its involvement in oxidative stress pathways. Here, we demonstrate for the first time that sulfatase exhibits peroxidase-like activity, catalyzing the generation of singlet oxygen (1O2) in the presence of oxygen. Based on the sulfatase-dependent 1O2 generation, the developed adamantly-enolether chemiluminescence probe QM-CF for imaging tumors of high sulfatase expression further verified the theory that sulfatase can be involved in tumor development. High-throughput screening (HTS) of natural compounds and clinical drugs identified scutellarin and sinomenine as potent sulfatase inhibitors that suppress tumor growth in mice. Mechanistic investigations revealed that these inhibitors modulate oxidative stress by downregulating MAPK and NF-κB pathways. Our findings unveil a previously unappreciated role of sulfatase in tumor-related oxidative stress and provide a promising platform for the discovery of novel sulfatase inhibitors, and advancing cancer therapeutics.

MOF-Based Single-Atom and Metal Cluster Catalysts by Room-Temperature Synthesis for Tumor Therapy

Metal-organic frameworks (MOFs) are widely used as substrates for creating single-atom catalysts due to their abundance of ligands, facilitating enzyme-like activity for biomedical applications. However, the high-temperature calcination process for single-atom catalysts limits economical, efficient, and large-scale synthesis. Here, a simple room-temperature synthesis of MOF-based single-atom and metal cluster catalysts is presented for tumor therapy. Fe/MOF is obtained through a coordination reaction at room temperature, while Au/MOF is synthesized from Au3+/MOF by introducing a reducing agent. Au/MOF effectively generates hydrogen peroxide (H2O2) from glucose, outperforming Au3+/MOF, and Fe/MOF subsequently produced hydroxyl radicals (•OH) by decomposing the generated H2O2via accelerated peroxidase-like activity in an acidic environment. In vitro and in vivo studies confirm a significantly enhanced cancer eradication ability compared to the PBS-treated group by combining cascade enzymatic activity, destruction of oxidative homeostasis, and excessive mitochondrial-mediated lipid peroxidation. The novel synthesis process of MOF-based metal single-atom catalysts establishes a new paradigm for fabricating effective enzyme-like nanomaterials for multimodal tumor therapy.

Microneedle-mediated hypoxic extracellular vesicle-encapsulated selenium nanoparticles delivery to treat androgenetic alopecia

Androgenetic alopecia (AGA) is the most common type of hair loss, and there is a lack of ideal treatment options. The damage and shedding of hair follicles are closely associated with niche dysregulation, including reactive oxygen species (ROS) accumulation, microvascular damage, and persistent inflammation. In this study, a biocomposite microneedle system comprising hypoxic extracellular vesicle (EV)-encapsulated selenium nanozyme (Se-HEVs-AMN) was designed to create a favorable perifollicular microenvironment. The novel Se-HEVs-AMN biocomposite patch features microneedles with sufficient mechanical strength, tailored dissolution properties, and a convenient detachable backing layer. The microneedles are modified with Astragalus polysaccharide (APS) and loaded with hypoxia-induced EVs containing selenium nanozyme. When applied to the dorsal skin of AGA mice, the microneedles rapidly dissolve, releasing active ingredients that increase hair density and enlarge hair follicle diameter through regulating inflammation, promoting angiogenesis, scavenging ROS, and resisting androgen.

Boron dipyrromethene fungicide for anti-microbial photodynamic therapeutics

Due to inadequate light transmission into the subsurface, one of the key challenges for conventional photodynamic therapy (PDT) is realizing successful treatment of deep-skin pathogenetic bacterial infectious wounds. Preparation of near-infrared (NIR) photosensitizers (PSs) with potent antibacterial activity is a potential solution to address this issue. In the present work, a boron dipyrromethene (BDP) derivative was synthesized, which had red light absorption and NIR fluorescence. Under 635 nm of irradiation, BDP could generate massive reactive oxygen species (ROS) for sterilization, which exhibited robust photodynamic antiseptic property against Gram-positive bacteria (S. aureus), with a minimum inhibitory concentration of only 240 nM (140 mW cm -2). More importantly, BDP was capable of efficiently suppressing the development of bacterial biofilms and even eliminate established biofilms, thereby facilitating the enhancement of sterilizing efficacy. Furthermore, the promising antibacterial capability of BDP was validated in the treatment of S. aureus-infected abscess. The present work presents an antibiotic-free strategy for highly effective light-triggered abscess therapy.

A Colorimetric/Fluorescence Dual Detection for Acid Phosphatase Based on Copper Nanoclusters

A simple and effective fluorescent/colorimetric dual detection was established toward acid phosphatase (ACP). Photoluminescent copper nanoclusters with blue emission were synthesized. These nanoclusters were also found with peroxidase-like activity and capable of accelerating the conversion of 3,3',5,5'-tetramethylbenzidine (TMB) into a colored oxidized form (oxTMB). As a strong ligand toward copper, pyrophosphate (PPi) inhibited this catalysis. When ACP was present, it hydrolyzed PPi into non-binding phosphate, and thus the inhibited catalysis was recovered. This brought in an increase in absorbance from oxTMB for a colorimetric signaling. Meanwhile, due to a good overlap of the emission of the CuNCs and absorption of oxTMB, the fluorescence signal was attenuated through inner filter effect (IFE). Both the increase of the absorption and decrease in fluorescence were applied for the quantification of ACP activity. The colorimetric signals provided a linear response toward ACP in the range 0.1-10 U/L, with a detection limit of 0.01 U/L, while the fluorimetry responded within 0.005-10 U/L, with a detection limit of 0.001 U/L. Because the same reagents and steps were applied, the method allowed a facile switching between these two modes, depending the performances required and instrumentations available. The applicability of the detection was validated through analysis of human serum samples.

A Magnetically Actuated MOF-Based Nanozyme for Intensified Induction of Ferroptosis and Immunogenic Cell Death Via Autophagy Blockade

Nanozymes mimicking enzymes show great promise in anti-tumor therapy but are often limited by their low catalytic activity and lack of tumor specificity in hostile tumor microenvironments. This study develops a novel nanozyme, D/P@ZUCO, utilizing metal-organic frameworks (MOFs) with glutathione oxidase, peroxidase, and catalase-like activities. D/P@ZUCO is synthesized using ZnFe2O4 and NH2-UiO66 (Cu/Zr) through an in situ growth method, followed by loading with doxorubicin (DOX) and primaquine (PQ), and functionalization with oxidized hyaluronic acid (OHA). It efficiently catalyzes the conversion of hydrogen peroxide (H2O2) into hydroxyl radicals (·OH) and glutathione (GSH) into glutathione disulfide (GSSH), initiating ferroptosis in cancer cells. Additionally, the conversion of excess H2O2 into oxygen (O2) enhances the apoptosis effects of DOX. Importantly, the inhibition of autophagy by D/P@ZUCO exacerbates ferroptosis and immunogenic cell death (ICD), triggering a potent anti-tumor immune response. The targeted drug delivery of D/P@ZUCO is facilitated by magnetic guidance and interactions between OHA and CD44 receptors. D/P@ZUCO demonstrates effective cancer treatment by triggering multiple cell death pathways through a synergistic combination of enzymatic actions, serving as a paradigm for systemic activation of multiple enzymes in triple-negative breast cancer therapy.

Nanozymes: a promising solution for dental antibacterial applications

Dental diseases pose significant public health challenges globally, affecting millions with conditions exacerbated by microbial-induced inflammation. Traditional natural enzymes, despite their antibacterial and anti-inflammatory capabilities, are limited by operational stability and environmental sensitivity. This review explores the revolutionary realm of nanozyme-artificial enzymes made from nanomaterials-which offer enhanced stability, cost-effectiveness, and ease of modification. We discuss the advent of nanozymes since their first recognition in 2007, emphasizing their enzyme-mimicking capabilities and applications in dental medicine, particularly for dental caries, pulpitis, periodontitis and peri-implantitis. This paper presents a comprehensive analysis of nanozymes' classification, mechanisms, and emerging applications, shedding light on their potential to revolutionize dental antibacterial treatments and addressing current challenges and future perspectives in their development.

Novel Metal-Free Nanozyme for Targeted Imaging and Inhibition of Atherosclerosis via Macrophage Autophagy Activation to Prevent Vulnerable Plaque Formation and Rupture

Atherosclerosis is a primary cause of cardiovascular and cerebrovascular diseases, with the unpredictable rupture of vulnerable atherosclerotic plaques enriched with lipid-laden macrophages being able to lead to heart attacks and strokes. Activating macrophage autophagy presents itself as a promising strategy for preventing vulnerable plaque formation and reducing the risk of rupture. In this study, we have developed a novel metal-free nanozyme (HCN@DS) that integrates the functions of multimodal imaging-guided therapy for atherosclerosis. HCN@DS has demonstrated high macrophage-targeting abilities due to its affinity toward scavenger receptor A (SR-A), along with excellent photoacoustic and photothermal imaging capabilities for guiding the precise treatment. It combines mild photothermal effects with moderate reactive oxygen species (ROS) generation to treat atherosclerosis. This controlled approach activates autophagy in atherosclerotic macrophages, inhibiting foam cell formation by reducing the uptake of oxidized low-density lipoproteins (oxLDL) and promoting efferocytosis and cholesterol efflux in macrophages. Additionally, it prevents plaque rupture by inhibiting apoptosis and inflammation within the plaque. Therefore, this metal-free nanozyme holds great potential for reducing the risk of atherosclerosis due to its high biosafety, excellent targeting ability, dual-modality imaging capability, and appropriate modulation of autophagy.

Nanozymes in cancer immunotherapy: metabolic disruption and therapeutic synergy

Over the past decade, there has been a growing emphasis on investigating the role of immunotherapy in cancer treatment. However, it faces challenges such as limited efficacy, a diminished response rate, and serious adverse effects. Nanozymes, a subset of nanomaterials, demonstrate boundless potential in cancer catalytic therapy for their tunable activity, enhanced stability, and cost-effectiveness. By selectively targeting the metabolic vulnerabilities of tumors, they can effectively intensify the destruction of tumor cells and promote the release of antigenic substances, thereby eliciting immune clearance responses and impeding tumor progression. Combined with other therapies, they synergistically enhance the efficacy of immunotherapy. Hence, a large number of metabolism-regulating nanozymes with synergistic immunotherapeutic effects have been developed. This review summarizes recent advancements in cancer immunotherapy facilitated by nanozymes, focusing on engineering nanozymes to potentiate antitumor immune responses by disturbing tumor metabolism and performing synergistic treatment. The challenges and prospects in this field are outlined. We aim to provide guidance for nanozyme-mediated immunotherapy and pave the way for achieving durable tumor eradication.

Electrochemical identification of reductive enantiomers in wood channels: A low-cost and scalable platform for chiral sensing

Chirality, an inherent characteristic of natural substances (such as sugars, peptides, proteins, and nucleic acid), plays a vital role in human metabolism and exerts substantial impacts. In general, chiral drugs can display diverse pharmacological and pharmacokinetic properties. One enantiomer may exhibit therapeutic effects, while the other could cause adverse reactions. Selective recognition of enantiomers is thus a significant task in the biomolecular and pharmaceutical fields. Despite the development of several chiral identification techniques, low-cost enantioselective sensing methods remain highly desirable. Here, we designed and developed an electrochemical sensing device for reductive enantiomer identification using natural wood channels as the substrate. The wood channels were endowed with oxidase-like activity through the in-situ growth of cerium oxide nanoparticles (CeO2). Chiral recognition capability was further introduced by incorporating a layer of chiral ZIF-8 (L-ZIF) as the chiral selector. To demonstrate the enantioselective sensing performance, 3,4-dihydroxyphenylalanine (DOPA) enantiomers were employed as model analytes. Due to the oxidase-like activity and the confinement effect of the proposed channels, the captured DOPA enantiomers were effectively oxidized to their quinone structure, and the Ce(IV) in CeO2 was reduced to Ce(III). These changes led to alterations in the surface charge of the channels, thereby modulating their ionic transport properties. This sensing mechanism also proved useful for the identification of other reductive enantiomers. The limits of detection for l-DOPA and d-DOPA were determined as 2.41 nM and 1.56 nM, respectively. The resulting wood channel-based sensing device not only can be used for the recognition and detection of reductive enantiomers, but also is expected to be applied to the non-electochemically active substances. Moreover, this study offers a novel type of solid-state channel material with low cost, reproducibility, and easy accessibility for electrochemical chiral sensing.

Catalytic Nanoparticles in Biomedical Applications: Exploiting Advanced Nanozymes for Therapeutics and Diagnostics

Catalytic nanoparticles (CNPs) as heterogeneous catalyst reveals superior activity due to their physio-chemical features, such as high surface-to-volume ratio and unique optical, electric, and magnetic properties. The CNPs, based on their physio-chemical nature, can either increase the reactive oxygen species (ROS) level for tumor and antibacterial therapy or eliminate the ROS for cytoprotection, anti-inflammation, and anti-aging. In addition, the catalytic activity of nanozymes can specifically trigger a specific reaction accompanied by the optical feature change, presenting the feasibility of biosensor and bioimaging applications. Undoubtedly, CNPs play a pivotal role in pushing the evolution of technologies in medical and clinical fields, and advanced strategies and nanomaterials rely on the input of chemical experts to develop. Herein, a systematic and comprehensive review of the challenges and recent development of CNPs for biomedical applications is presented from the viewpoint of advanced nanomaterial with unique catalytic activity and additional functions. Furthermore, the biosafety issue of applying biodegradable and non-biodegradable nanozymes and future perspectives are critically discussed to guide a promising direction in developing span-new nanozymes and more intelligent strategies for overcoming the current clinical limitations.

Two-dimensional metal organic frameworks in cancer treatment

With large specific surface area, controllable pore size, increased active sites, and structural stability, two-dimensional metal organic frameworks (2D MOFs) have emerged as promising nanomedicines in cancer therapy. These distinctive features make 2D MOFs particularly advantageous in cancer treatment and the corresponding application has gained considerable popularity, signifying significant application potential. Herein, recent advances in various applications including drug delivery and chemotherapy, photodynamic therapy, sonodynamic therapy, chemodynamic therapy, catalytic therapy, and combined therapy were summarized, with emphasis on the latest progress of new materials and mechanisms for these processes. Moreover, the current challenges, potential solutions, and possible future directions are discussed as well.

Macrophage-Biomimetic Nanoplatform-Based Therapy for Inflammation-Associated Diseases

Inflammation-associated diseases are very common clinically with a high incidence; however, there is still a lack of effective treatments. Cell-biomimetic nanoplatforms have led to many breakthroughs in the field of biomedicine, significantly improving the efficiency of drug delivery and its therapeutic implications especially for inflammation-associated diseases. Macrophages are an important component of immune cells and play a critical role in the occurrence and progression of inflammation-associated diseases while simultaneously maintaining homeostasis and modulating immune responses. Therefore, macrophage-biomimetic nanoplatforms not only inherit the functions of macrophages including the inflammation tropism effect for targeted delivery of drugs and the neutralization effect of pro-inflammatory cytokines and toxins via membrane surface receptors or proteins, but also maintain the functions of the inner nanoparticles. Macrophage-biomimetic nanoplatforms are shown to have remarkable therapeutic efficacy and excellent application potential in inflammation-associated diseases. In this review, inflammation-associated diseases, the physiological functions of macrophages, and the classification and construction of macrophage-biomimetic nanoplatforms are first introduced. Next, the latest applications of different macrophage-biomimetic nanoplatforms for the treatment of inflammation-associated diseases are summarized. Finally, challenges and opportunities for future biomedical applications are discussed. It is hoped that the review will provide new ideas for the further development of macrophage-biomimetic nanoplatforms.

Porous reticular Co@Fe metal-organic gel: dual-function simulated peroxidase nanozyme for both colorimetric sensing and antibacterial applications

Constructing metal-organic gels (MOGs) with enzyme-catalyzed activity and studying their catalytic mechanism are crucial for the development of novel nanozyme materials. In this study, a Co@Fe MOG with excellent peroxidase activity was developed by a simple and mild one-pot process. The results showed that the material exhibited almost a single peroxidase activity under optimal pH conditions, which allowed it to attract and oxidize the chromogenic substrate 3,3',5,5'-tetramethylbenzidine (TMB). Based on the active electron transfer between the metal centers and the organic ligand in the synthetic material, the Co@Fe MOG-H2O2-TMB system was verified to be able to detect H2O2 and citric acid (CA). The catalytic microenvironment formed by the adsorption and the catalytic center accelerated the electron-transfer rate, which expedited the generation of hydroxyl radicals (˙OH, a kind of reactive oxygen species (ROS)) in the presence of H2O2. The persistence and high intensity of ˙OH generation were proven, which would endow Co@Fe MOG with a certain antibacterial ability, promoting the healing of bacteria-infected wounds. In conclusion, this study contributes to the development efforts toward the application systems of nanozymes for marker detection and antibacterial activity.

Synergistic and antibiofilm activity of DNase I and glucose oxidase loaded chitosan nanoparticles against dual-species biofilms of Listeria monocytogenes and Salmonella

Salmonella and Listeria monocytogenes are two of the most common foodborne pathogens in the food industry. They form dual-species biofilms, which have a higher sensitivity to antimicrobial treatment and a greater microbial adhesion. In this experiment, we loaded DNase I and glucose oxidase (GOX) on chitosan nanoparticles (CSNPs) to explore their inhibitory effects on and disruption of dual-species biofilms of Salmonella enterica and L. monocytogenes. Transmission electron microscopy (TEM) showed that CSNP-DNase-GOX and CSNPs were spherical in shape. CSNP-DNase-GOX was shifted and altered compared to the infrared peaks of CSNPs. CSNPs loaded with DNase I and GOX showed an increase in the particle size and an alteration in the polydispersity index (PDI) and the zeta potential. Compared to free DNase I or GOX, DNase I and GOX loaded on CSNPs had higher stability at different temperatures. CSNP-DNase-GOX was more effective in inhibiting dual-species biofilms than CSNP-GOX. Scanning electron microscopy (SEM) and fluorescence microscopy were used to observe the structure of the biofilm, which further illustrated that CSNP-DNase-GOX disrupted the dual-species biofilms of S. enterica and L. monocytogenes.

Tailoring Biomaterials Ameliorate Inflammatory Bone Loss

Inflammatory diseases, such as rheumatoid arthritis, periodontitis, chronic obstructive pulmonary disease, and celiac disease, disrupt the delicate balance between bone resorption and formation, leading to inflammatory bone loss. Conventional approaches to tackle this issue encompass pharmaceutical interventions and surgical procedures. Nevertheless, pharmaceutical interventions exhibit limited efficacy, while surgical treatments impose trauma and significant financial burden upon patients. Biomaterials show outstanding spatiotemporal controllability, possess a remarkable specific surface area, and demonstrate exceptional reactivity. In the present era, the advancement of emerging biomaterials has bestowed upon more efficacious solutions for combatting the detrimental consequences of inflammatory bone loss. In this review, the advances of biomaterials for ameliorating inflammatory bone loss are listed. Additionally, the advantages and disadvantages of various biomaterials-mediated strategies are summarized. Finally, the challenges and perspectives of biomaterials are analyzed. This review aims to provide new possibilities for developing more advanced biomaterials toward inflammatory bone loss.

Multi-Enzyme Activity of MIL-101 (Fe)-Derived Cascade Nano-Enzymes for Antitumor and Antimicrobial Therapy

The clinical application of oncology therapy is hampered by high glutathione concentrations, hypoxia, and inefficient activation of cell death mechanisms in cancer cells. In this study, Fe and Mo bimetallic sulfide nanomaterial (FeS2@MoS2) based on metal-organic framework structure is rationally prepared with peroxidase (POD)-, catalase (CAT)-, superoxide dismutase (SOD)-like activities and glutathione depletion ability, which can confer versatility for treating tumors and mending wounds. In the lesion area, FeS2@MoS2 with SOD-like activity can facilitate the transformation of superoxide anions (O2 -) to hydrogen peroxide (H2O2), and then the resulting H2O2 serves as a substrate for the Fenton reaction with FMS to produce highly toxic hydroxyl radicals (∙OH). Simultaneously, FeS2@MoS2 has an ability to deplete glutathione (GSH) and catalyze the decomposition of nicotinamide adenine dinucleotide phosphate (NADPH) to curb the regeneration of GSH from the source. Thus it can realize effective tumor elimination through synergistic apoptosis-ferroptosis strategy. Based on the alteration of the H2O2 system, free radical production, glutathione depletion and the alleviation of hypoxia in the tumor microenvironment, FeS2@MoS2 NPS can not only significantly inhibit tumors in vivo and in vitro, but also inhibit multidrug-resistant bacteria and hasten wound healing. It may open the door to the development of cascade nanoplatforms for effective tumor treatment and overcoming wound infection.

Surface Ligand Engineering Ruthenium Nanozyme Superior to Horseradish Peroxidase for Enhanced Immunoassay

Nanozymes have great potential to be used as an alternative to natural enzymes in a variety of fields. However, low catalytic activity compared with natural enzymes limits their practical use. It is still challenging to design nanozymes comparable to their natural counterparts in terms of the specific activity. In this study, a surface engineering strategy is employed to improve the specific activity of Ru nanozymes using charge-transferrable ligands such as polystyrene sulfonate (PSS). PSS-modified Ru nanozyme exhibits a peroxidase-like specific activity of up to 2820 U mg-1 , which is twice that of horseradish peroxidase (1305 U mg-1 ). Mechanism studies suggest that PSS readily accepts negative charge from Ru, thus reducing the affinity between Ru and ·OH. Importantly, the modified Ru-peroxidase nanozyme is successfully used to develop an immunoassay for human alpha-fetoprotein and achieves a 140-fold increase in detection sensitivity compared with traditional horseradish-peroxidase-based enzyme-linked immunosorbent assay. Therefore, this work provides a feasible route to design nanozymes with high specific activity that meets the practical use as an alternative to natural enzymes.

Nanozyme-Engineered Hydrogels for Anti-Inflammation and Skin Regeneration

Inflammatory skin disorders can cause chronic scarring and functional impairments, posing a significant burden on patients and the healthcare system. Conventional therapies, such as corticosteroids and nonsteroidal anti-inflammatory drugs, are limited in efficacy and associated with adverse effects. Recently, nanozyme (NZ)-based hydrogels have shown great promise in addressing these challenges. NZ-based hydrogels possess unique therapeutic abilities by combining the therapeutic benefits of redox nanomaterials with enzymatic activity and the water-retaining capacity of hydrogels. The multifaceted therapeutic effects of these hydrogels include scavenging reactive oxygen species and other inflammatory mediators modulating immune responses toward a pro-regenerative environment and enhancing regenerative potential by triggering cell migration and differentiation. This review highlights the current state of the art in NZ-engineered hydrogels (NZ@hydrogels) for anti-inflammatory and skin regeneration applications. It also discusses the underlying chemo-mechano-biological mechanisms behind their effectiveness. Additionally, the challenges and future directions in this ground, particularly their clinical translation, are addressed. The insights provided in this review can aid in the design and engineering of novel NZ-based hydrogels, offering new possibilities for targeted and personalized skin-care therapies.

Old trees bloom new flowers, lysosome targeted near-infrared fluorescent probe for ratiometric sensing of hypobromous acid in vitro and in vivo based on Nile red skeleton

Hypobromous acid (HOBr), one of the significant reactive oxygen species (ROS) that acts as an important role in human immune system, however the increasing level of HOBr in human body can cause the disorder of eosinophils (EPO), leading to oxidative stress in organelles, and further causing a series of diseases. In this study, a ratiometric fluorescent probe DMBP based on Nile red skeleton was developed to detect HOBr specifically by the electrophilic substitution with HOBr. DMBP emits near-infrared (NIR) fluorescence at 653 nm, after reacting with HOBr, the emission wavelength of DMBP shifted blue and a new peak appeared at 520 nm, realizing a ratiometric examination of HOBr with a limit of detection of 89.00 nM. Based on its sensitive and specific response to HOBr, DMBP was applied in the visual imaging of HOBr in HepG2 cells and zebrafish. Foremost, probe DMBP has excellent lysosome targeting ability and NIR emission reduced the background interference of biological tissues, providing a potential analytical tool to further investigate the role of HOBr in lysosome.

Reactive Oxygen Species Scavenging Nanozymes: Emerging Therapeutics for Acute Liver Injury Alleviation

Acute liver injury (AIL), a fatal clinical disease featured with a swift deterioration of hepatocyte functions in the short term, has emerged as a serious public health issues that warrants attention. However, the effectiveness of existing small molecular antioxidants and anti-inflammatory medications in alleviating AIL remains uncertain. The unique inherent structural characteristics of liver confer it a natural propensity for nanoparticle capture, which present an opportunity to exploit in the formulation of nanoscale therapeutic agents, enabling their selective accumulation in the liver and thereby facilitating targeted therapeutic interventions. Significantly increased reactive oxygen species (ROS) accumulation and inflammation response have been evidenced to play crucial roles in occurrence and development of AIL. Nanozymes with ROS-scavenging capacities have demonstrated considerable promise in ROS elimination and inflammation regulation, thereby offering an appealing therapeutic instrument for the management of acute liver injury. In this review, the mechanisms of different type of ALI were summarized. In addition, we provide a comprehensive summary and review of the available ROS-scavenging nanozymes, including transition metal-based nanozymes, noble metal nanozymes, carbon-based nanozymes, and some other nanozymes. Furthermore, the challenges still need to be solved in the field of ROS-scavenging nanozymes for ALI alleviation are also discussed.

Synergistic anti-oxidant and anti-inflammatory effects of ceria/resatorvid co-decorated nanoparticles for acute lung injury therapy

BACKGROUND

Acute lung injury (ALI) is a critical inflammatory response syndrome that rapidly develops into acute respiratory distress syndrome (ARDS). Currently, no effective therapeutic modalities are available for patients with ALI/ARDS. According to recent studies, inhibiting both the release of pro-inflammatory cytokines and the formation of reactive oxygen species (ROS) as early as possible may be a promising therapy for ALI.

RESULTS

In this study, a ROS-responsive nano-delivery system based on oxidation-sensitive chitosan (Ox-CS) was fabricated for the simultaneous delivery of Ce NPs and RT. The in vitro experiments have shown that the Ox-CS/Ceria-Resatorvid nanoparticles (Ox-CS/CeRT NPs) were rapidly and efficiently internalised by inflammatory endothelial cells. Biological evaluations validated the significant attenuation of ROS-induced oxidative stress and cell apoptosis by Ox-CS/CeRT NPs, while maintaining mitochondrial function. Additionally, Ox-CS/CeRT NPs effectively inhibited the release of pro-inflammatory factors. After intraperitoneal (i.p.) administration, Ox-CS/CeRT NPs passively targeted the lungs of LPS-induced inflamed mice and released the drug activated by the high ROS levels in inflammatory tissues. Finally, Ox-CS/CeRT NPs significantly alleviated LPS-induced lung injury through inhibiting both oxidative stress and pro-inflammatory cytokine expression.

CONCLUSIONS

The created Ox-CS/CeRT NPs could act as a prospective nano-delivery system for a combination of anti-inflammatory and anti-oxidant therapy of ALI.

Ultrathin 2D Pd/Cu Single-Atom MOF Nanozyme to Synergistically Overcome Chemoresistance for Multienzyme Catalytic Cancer Therapy

Single-atom nanozymes (SAzymes) have obtained increasing interest to mimic natural enzymes for efficient cancer therapy, while challenged by chemoresistance from cellular redox homeostasis and the interface of reductive species in tumor microenvironment (TME). Herein, a dual single-atomic ultrathin 2D metal organic framework (MOF) nanosheet of multienzyme (Pd/Cu SAzyme@Dzy) is prepared to synergistically overcome chemoresistance for multienzyme enhanced cancer catalytic therapy. The Pd SAzyme exhibits peroxidase (POD)-like catalytic activity for overcoming chemoresistance via disturbing cellular redox balance. This is further enhanced by cascade generation of more ∙OH via Cu+ -catalyzed POD-like reactions, initiated by in situ-reduction of Cu2+ into Cu+ upon GSH depletion. This process can also avoid the consumption of ∙OH by endogenous reductive GSH in TME, ensuring the adequate amount of ∙OH for highly efficient therapy. Besides, the DNAzyme is also delivered for gene therapy of silencing cancer-cell-targeting VEGFR2 protein to further enhance the therapy. Based on both experiments and theoretical calculations, the synergetic multienzyme-based cancer therapy is examined and the enhancement by the cascade tumor antichemoresistance is revealed.

Pulmonary endothelium-targeted nanoassembly of indomethacin and superoxide dismutase relieves lung inflammation

Lung inflammation is an essential inducer of various diseases and is closely related to pulmonary-endothelium dysfunction. Herein, we propose a pulmonary endothelium-targeted codelivery system of anti-inflammatory indomethacin (IND) and antioxidant superoxide dismutase (SOD) by assembling the biopharmaceutical SOD onto the "vector" of rod-like pure IND crystals, followed by coating with anti-ICAM-1 antibody (Ab) for targeting endothelial cells. The codelivery system has a 237 nm diameter in length and extremely high drug loading of 39% IND and 2.3% SOD. Pharmacokinetics and biodistribution studies demonstrate the extended blood circulation and the strong pulmonary accumulation of the system after intravenous injection in the lipopolysaccharide (LPS)-induced inflammatory murine model. Particularly, the system allows a robust capacity to target pulmonary endothelium mostly due to the rod-shape and Ab coating effect. In vitro, the preparation shows the synergistic anti-inflammatory and antioxidant effects in LPS-activated endothelial cells. In vivo, the preparation exhibits superior pharmacodynamic efficacy revealed by significantly downregulating the inflammatory/oxidative stress markers, such as TNF-α, IL-6, COX-2, and reactive oxygen species (ROS), in the lungs. In conclusion, the codelivery system based on rod-like pure crystals could well target the pulmonary endothelium and effectively alleviate lung inflammation. The study offers a promising approach to combat pulmonary endothelium-associated diseases.

A nanozyme-reinforced injectable photodynamic hydrogel for combating biofilm infection

Bacterial biofilm-associated infectious diseases remain serious menaces to human health. Recently, photodynamic therapy (PDT) has become a prospective strategy for combating biofilm infection. However, anaerobic conditions in a biofilm greatly inhibit its therapeutic efficacy. Here, a nanozyme-reinforced injectable hydrogel is prepared using Ca2+-crosslinked sodium alginate incorporated with photosensitizer-loaded MnO2 nanosheets and CaO2 nanoparticles for O2 self-sufficient PDT to eradicate biofilm infection. In our design, CaO2 reacts with water to produce locally concentrated H2O2, which could be catalyzed by MnO2 nanosheets (catalase-mimic nanozymes) to generate O2 and greatly relieve the hypoxic conditions in the biofilm, thus significantly strengthening PDT efficacy. In vitro assays confirmed that the hybrid hydrogel not only exhibits high-performance bactericidal activity in combating both Gram-positive Staphylococcus aureus and Gram-negative Escherichia coli but also shows great efficacy in eliminating biofilm infection. Moreover, benefiting from its good syringeability, the hybrid hydrogel is prone to fit irregular wounds and exhibits high efficiency in promoting wound healing in a biofilm-infected mice model. Besides, no obvious toxicity is detected in the hybrid hydrogel. Overall, we envision that our designed hydrogel could provide a prospective solution for combating biofilm-associated infections.

Recent Advances in Nanozyme-Based Materials for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is a type of chronic inflammatory disorder that interferes with the patient's lifestyle and, in extreme situations, can be deadly. Fortunately, with the ever-deepening understanding of the pathological cause of IBD, recent studies using nanozyme-based materials have indicated the potential toward effective IBD treatment. In this review, the recent advancement of nanozymes for the treatment of enteritis is summarized from the perspectives of the structural design of nanozyme-based materials and therapeutic strategies, intending to serve as a reference to produce effective nanozymes for moderating inflammation in the future. Last but not least, the potential and current restrictions for using nanozymes in IBD will also be discussed. In short, this review may provide a guidance for the development of innovative enzyme-mimetic nanomaterials that offer a novel and efficient approach toward the effective treatment of IBD.

Engineering Self-Assembled Nanomedicines Composed of Clinically Approved Medicines for Enhanced Tumor Nanotherapy

The traditional nanocarriers are typically constructed to deliver anticancer agents for improving drug bioavailability and enhancing chemotherapeutic efficacy, but this strategy suffers from the critical issue of nanocarrier biosafety that hinders further clinical translation. In this work, a unique nanomedicine (PTX@ICG) has been rationally constructed by combining two clinically approved agents, i.e., paclitaxel (PTX) and indocyanine green (ICG), by a facile ultrasound-assisted self-assembly methodology. The formation of the nanostructure can effectively increase the enrichment of PTX and ICG molecules in the tumor site, and improve the utilization factor of hydrophobic PTX. Moreover, since the molecule interaction in PTX@ICG is mainly Van der Waals forces, the self-assembled structure can be spontaneously dissociated under laser irradiation and release PTX in situ to achieve safe tumor-targeted chemotherapy. Simultaneously, the released ICG can act as photothermic agents for photothermal therapy (PTT), thus combining chemotherapy and PTT to obtain an enhanced tumor nanotherapy via facile self-assembly. The synergistic chemo/photothermal tumor nanotherapy achieved the efficient tumor cell-killing effect and tumor-ablation ability, as systematically demonstrated both in vitro and in vivo. This work provides a distinct paradigm of the self-assembled nanomedicine design for effectively improving the drug bioavailability to achieve high antitumor efficacy.

Engineered Nano-Bio Interfaces for Stem Cell Therapy

Engineered nanomaterials (ENMs) with different topographies provide effective nano-bio interfaces for controlling the differentiation of stem cells. The interaction of stem cells with nanoscale topographies and chemical cues in their microenvironment at the nano-bio interface can guide their fate. The use of nanotopographical cues, in particular nanorods, nanopillars, nanogrooves, nanofibers, and nanopits, as well as biochemical forces mediated factors, including growth factors, cytokines, and extracellular matrix proteins, can significantly impact stem cell differentiation. These factors were seen as very effective in determining the proliferation and spreading of stem cells. The specific outgrowth of stem cells can be decided with size variation of topographic nanomaterial along with variation in matrix stiffness and surface structure like a special arrangement. The precision chemistry enabled controlled design, synthesis, and chemical composition of ENMs can regulate stem cell behaviors. The parameters of size such as aspect ratio, diameter, and pore size of nanotopographic structures are the main factors for specific termination of stem cells. Protein corona nanoparticles (NPs) have shown a powerful facet in stem cell therapy, where combining specific proteins could facilitate a certain stem cell differentiation and cellular proliferation. Nano-bio reactions implicate the interaction between biological entities and nanoparticles, which can be used to tailor the stem cells' culmination. The ion release can also be a parameter to enhance cellular proliferation and to commit the early differentiation of stem cells. Further research is needed to fully understand the mechanisms underlying the interactions between engineered nano-bio interfaces and stem cells and to develop optimized regenerative medicine and tissue engineering designs.

Development of nanozymes for promising alleviation of COVID-19-associated arthritis

The COVID-19 pandemic caused by SARS-CoV-2 has been identified as a culprit in the development of a variety of disorders, including arthritis. Although the emergence of arthritis following SARS-CoV-2 infection may not be immediately discernible, its underlying pathogenesis is likely to involve a complex interplay of infections, oxidative stress, immune responses, abnormal production of inflammatory factors, cellular destruction, etc. Fortunately, recent advancements in nanozymes with enzyme-like activities have shown potent antiviral effects and the ability to inhibit oxidative stress and cytokines and provide immunotherapeutic effects while also safeguarding diverse cell populations. These adaptable nanozymes have already exhibited efficacy in treating common types of arthritis, and their distinctive synergistic therapeutic effects offer great potential in the fight against arthritis associated with COVID-19. In this comprehensive review, we explore the potential of nanozymes in alleviating arthritis following SARS-CoV-2 infection by neutralizing the underlying factors associated with the disease. We also provide a detailed analysis of the common therapeutic pathways employed by these nanozymes and offer insights into how they can be further optimized to effectively address COVID-19-associated arthritis.

Microneedle-Assisted Transdermal Delivery of 2D Bimetallic Metal-Organic Framework Nanosheet-Based Cascade Biocatalysts for Enhanced Catalytic Therapy of Melanoma

Current conventional treatments for malignant melanoma still face limitations, especially low therapeutic efficacy and serious side effects, and more effective strategies are urgently needed to develop them. Delivering biocatalysts into tumors to efficiently trigger in situ cascade reactions has shown huge potential in producing more therapeutic species or generating stronger tumoricidal effects for augmented tumor therapy. Recently, ultrathin 2D metal-organic framework (MOF) nanosheets have acquired great interest in biocatalysis owing to their large surface areas and abundant accessible active catalytic sites. Herein, an enhanced catalytic therapeutic strategy against melanoma is developed by biocompatible microneedle (MN)-assisted transdermal delivery of a 2D bimetallic MOF nanosheet-based cascade biocatalyst (Cu-TCPP(Fe)@GOD). Profiting from the constructed dissolving MN system, the loaded Cu-TCPP(Fe)@GOD hybrid nanosheets can be accurately delivered into the melanoma sites through skin barriers, and subsequently, trigger the specific cascade catalytic reactions in response to the acidic tumor microenvironment to effectively generate highly toxic hydroxyl radical (^• OH) and deplete glucose nutrient for inducing the death of melanoma cells. The ultimate results prove the high melanoma inhibition effect and biosafety of such therapeutic modality, exhibiting a new and promising strategy to conquer malignant melanoma.

Nanosystems for oxidative stress regulation in the anti-inflammatory therapy of acute kidney injury

Acute kidney injury (AKI) is a clinical syndrome that results from a rapid decline in renal structure or renal functional impairment with the main pathological feature of sublethal and lethal damage to renal tubular cells. However, many potential therapeutic agents cannot achieve the desired therapeutic effect because of their poor pharmacokinetics and short retention time in the kidneys. With the recent emergence and progress of nanotechnology, nanodrugs with unique physicochemical properties could prolong circulation time, enhance efficient targeted delivery, and elevate the accumulation of therapeutics that can cross the glomerular filtration barrier and indicate comprehensive application prospects in the prevention and treatment of AKI. In this review, various types of nanosystems (such as liposomes, polymeric nanosystems, inorganic nanoparticles and cell-derived extracellular vesicles) are designed and applied to improve the pharmacokinetics of drug formation, which could further relieve the burden on the kidneys caused by the final cumulative dose of drugs in conventional treatments. Moreover, the passive or active targeting effect of nanosystems can also reduce the total therapeutic dose and off-target adverse effects on other organs. Nanodelivery systems for treating AKI that alleviate oxidative stress-induced renal cell damage and regulate the inflammatory kidney microenvironment are summarized.

A metabolic intervention strategy to break evolutionary adaptability of tumor for reinforced immunotherapy

The typical hallmark of tumor evolution is metabolic dysregulation. In addition to secreting immunoregulatory metabolites, tumor cells and various immune cells display different metabolic pathways and plasticity. Harnessing the metabolic differences to reduce the tumor and immunosuppressive cells while enhancing the activity of positive immunoregulatory cells is a promising strategy. We develop a nanoplatform (CLCeMOF) based on cerium metal-organic framework (CeMOF) by lactate oxidase (LOX) modification and glutaminase inhibitor (CB839) loading. The cascade catalytic reactions induced by CLCeMOF generate reactive oxygen species "storm" to elicit immune responses. Meanwhile, LOX-mediated metabolite lactate exhaustion relieves the immunosuppressive tumor microenvironment, preparing the ground for intracellular regulation. Most noticeably, the immunometabolic checkpoint blockade therapy, as a result of glutamine antagonism, is exploited for overall cell mobilization. It is found that CLCeMOF inhibited glutamine metabolism-dependent cells (tumor cells, immunosuppressive cells, etc.), increased infiltration of dendritic cells, and especially reprogrammed CD8+ T lymphocytes with considerable metabolic flexibility toward a highly activated, long-lived, and memory-like phenotype. Such an idea intervenes both metabolite (lactate) and cellular metabolic pathway, which essentially alters overall cell fates toward the desired situation. Collectively, the metabolic intervention strategy is bound to break the evolutionary adaptability of tumors for reinforced immunotherapy.

Innovative strategies for photodynamic therapy against hypoxic tumor

Photodynamic therapy (PDT) is applied as a robust therapeutic option for tumor, which exhibits some advantages of unique selectivity and irreversible damage to tumor cells. Among which, photosensitizer (PS), appropriate laser irradiation and oxygen (O₂) are three essential components for PDT, but the hypoxic tumor microenvironment (TME) restricts the O₂ supply in tumor tissues. Even worse, tumor metastasis and drug resistance frequently happen under hypoxic condition, which further deteriorate the antitumor effect of PDT. To enhance the PDT efficiency, critical attention has been received by relieving tumor hypoxia, and innovative strategies on this topic continue to emerge. Traditionally, the O₂ supplement strategy is considered as a direct and effective strategy to relieve TME, whereas it is confronted with great challenges for continuous O₂ supply. Recently, O₂-independent PDT provides a brand new strategy to enhance the antitumor efficiency, which can avoid the influence of TME. In addition, PDT can synergize with other antitumor strategies, such as chemotherapy, immunotherapy, photothermal therapy (PTT) and starvation therapy, to remedy the inadequate PDT effect under hypoxia conditions. In this paper, we summarized the latest progresses in the development of innovative strategies to improve PDT efficacy against hypoxic tumor, which were classified into O₂-dependent PDT, O₂-independent PDT and synergistic therapy. Furthermore, the advantages and deficiencies of various strategies were also discussed to envisage the prospects and challenges in future study.

A Light-Responsive Injectable Hydrogel with Remodeling Tumor Microenvironment for Light-Activated Chemodynamic Therapy

Chemodynamic therapy (CDT) based on Fenton-like reaction is often limited by the tumor microenvironment (TME), which has insufficient hydrogen peroxide, and single CDT treatment is often less efficacious. To overcome these limitations, a hydrogel-based system is designed to enhance the redox stress (EOH) by loading the composite nanomaterial Cu-Hemin-Au, into the agarose hydrogels. The hydrogels can reach the tumor site upon intratumoral injection, and then coagulate and stay for extended period. Once irradiated with near-infrared light, the Cu-Hemin-Au act as a photothermal agent to convert the light energy into heat, and the EOH gradually heated up and softened, releasing the Cu-Hemin-Au residing in it to achieve photothermal therapy (PTT). Benefiting from the glucose oxidase (GOx)-like activity of the Au nanoparticles, glucose in the tumor cells is largely consumed, and hydrogen peroxide (H₂ O₂ ) is generated in situ, and then Cu-Hemin-Au react with sufficient H₂ O₂ to generate a large amount of reactive oxygen species, which promote the complete inhibition of tumor growth in mice during the treatment cycle. The hydrogel system for the synergistic enhancement of oxidative stress achieves good PTT/CDT synergy, providing a novel inspiration for the next generation of hydrogels for application in antitumor therapy.

Low dimensional nanomaterials for treating acute kidney injury

Acute kidney injury (AKI) is one of the most common severe complications among hospitalized patients. In the absence of specific drugs to treat AKI, hemodialysis remains the primary clinical treatment for AKI patients. AKI treatment has received significant attention recently due to the excellent drug delivery capabilities of low-dimensional nanomaterials (LDNs) and their unique therapeutic effects. Diverse LDNs have been proposed to treat AKI, with promising results and the potential for future clinical application. This article aims to provide an overview of the pathogenesis of AKI and the recent advances in the treatment of AKI using different types of LDNs. In addition, it is intended to provide theoretical support for the design of LDNs and implications for AKI treatment.

Newly developed gas-assisted sonodynamic therapy in cancer treatment

Sonodynamic therapy (SDT) is an emerging noninvasive treatment modality that utilizes low-frequency and low-intensity ultrasound (US) to trigger sensitizers to kill tumor cells with reactive oxygen species (ROS). Although SDT has attracted much attention for its properties including high tumor specificity and deep tissue penetration, its anticancer efficacy is still far from satisfactory. As a result, new strategies such as gas-assisted therapy have been proposed to further promote the effectiveness of SDT. In this review, the mechanisms of SDT and gas-assisted SDT are first summarized. Then, the applications of gas-assisted SDT for cancer therapy are introduced and categorized by gas types. Next, therapeutic systems for SDT that can realize real-time imaging are further presented. Finally, the challenges and perspectives of gas-assisted SDT for future clinical applications are discussed.

Colon cancer exosome-derived biomimetic nanoplatform for curcumin-mediated sonodynamic therapy and calcium overload

Sonodynamic therapy (SDT) possesses unique properties such as being minimally invasive, exhibiting low toxicity, as well as ability to impart the treatment in the deep tissues, and hence has been extensively used. However, inherent defects such as low water-soluble sonosensitizers can limit the clinical application of SDT, and tumor microenvironment (TME) can further compromise the effect of a single SDT. To overcome these challenges, we have designed a bionic nano-system (ECaC) by coating mesoporous calcium carbonate nanoparticles (CaCO3 NPs) and sonosensitizer curcumin (Cur) into tumor-derived exosomes for developing enhanced SDT. Exosome membrane could endow CaCO3 NPs with homologous targeting abilities. In addition, compared with the bare CaCO3 NPs, ECaC showed significant accumulation in the tumor cell species. Subsequently, CaCO3 NPs upon reaching the tumor site can be degraded into Ca2+ in response to the acidic microenvironment of the tumor to destroy the cellular mitochondria. Hence, the cellular respiration could be destroyed to be a vulnerable state, causing oxidative stress, enhancing Cur-mediated chemotherapy/SDT. This synergistically dynamic therapy has demonstrated significant anti-tumor effects under in vitro and in vivo settings without exhibiting any toxic side effects. Our prepared biomimetic nano-system can effectively deliver the hydrophobic Cur to the tumor sites, which holds great promise in field of drug delivery and can broaden the application of exosomes, as this method has a certain enlightenment effect on the subsequent development of exosomes.

Antioxidant nanozymes for prevention of diseased kidney from failure

Oxidative stress is a state of excessive free radicals and is commonly found with diseased kidneys. Therefore, development of antioxidant-based therapy has been of great interest to biomedical scientists for kidney disease management. One of the drawbacks of using natural antioxidants is their low bioavailability, which limits their anti-free radical efficacy. This commentary discusses novel antioxidant gold-platinum nanoparticles and their potential for prevention of kidney failure in patients who are diagnosed with chronic kidney disease.

Novel gold-platinum nanoparticles serve as broad-spectrum antioxidants for attenuating ischemia reperfusion injury of the kidney

Kidney ischemia reperfusion injury (IRI) is a common and inevitable pathological condition in routine urological practices, especially during transplantation. Severe kidney IRI may even induce systemic damage to peripheral organs, and lead to multisystem organ failure. However, no standard clinical treatment option is currently available. It has been reported that kidney IRI is predominantly associated with abnormally increased endogenous reactive oxygen species (ROS). Scavenging excessive ROS may reduce the damage caused by oxidative stress and subsequently alleviate kidney IRI. Here, we reported a simple and efficient one-step synthesis of gold-platinum nanoparticles (AuPt NPs) with a gold core having a loose and branched outer platinum shell with superior ROS scavenging capacity to possibly treat kidney IRI. These AuPt NPs exhibited multiple enzyme-like anti-oxidative properties simultaneously possessing catalase- and peroxidase-like activity. These particles showed excellent cell protective capability, and alleviated kidney IRI both in vitro and in vivo without obvious toxicity, by suppressing cell apoptosis, inflammatory cytokine release, and inflammasome formation. Meanwhile, AuPt NPs also had an effect on inhibiting the transition to chronic kidney disease by reducing kidney fibrosis in the long term. Thus, AuPt NPs might be a good therapeutic agent for kidney IRI management and may be helpful for the development of clinical treatments for kidney IRI.

Inhibition of UV-B stress in lettuce through enzyme-like Scutellaria baicalensis carbon dots

Oxidative stress in plants caused by UV-B stress has always been a great challenge to the yield of agricultural products. Carbon dots (CDs) with enzyme-like activity have been developed, and inhibiting oxidative stress in animals has been achieved, but little is known about abiotic stress resistance in plants, especially UV-B stress. In this study, CDs were synthesized from Scutellaria baicalensis via a hydrothermal method. The ability of CDs to scavenge reactive oxygen species (ROS) in vivo and in vitro and to enhance antioxidant resistance in vivo was evaluated. The results show that CDs promoted the nutrient assimilation ability of lettuce seedlings and protected the plants from UV-B stress by increasing the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), glutathione reductase (GR), and ascorbate peroxidase (APX). Moreover, the antioxidant metabolism of plants can be activated by CDs and the expression levels of aquaporin (AQP) genes PIP1 and PIP2 are also up-regulated. These results facilitate the design and fabrication of CDs to meet the challenge of abiotic stress in food production.

Cancer Cell Membrane Biomimetic Mesoporous Nanozyme System with Efficient ROS Generation for Antitumor Chemoresistance

Single-atom nanozymes (SAZs) with reaction specificity and optimized catalytic properties have great application prospects in tumor therapy. But the complex tumor microenvironment (low content of H2O2) limits its therapeutic effect. In this study, we developed a bionic mesoporous Fe SAZs/DDP nanosystem (CSD) for enhanced nanocatalytic therapy (NCT)/chemotherapy by simultaneously encapsulating the chemotherapeutic drugs cisplatin (DDP) and Fe SAZs with high peroxidase (POD) activity into the cancer cell membrane. CSD could evade immune recognition and actively targets tumor sites, and DDP upregulates endogenous H2O2 levels by activating nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, thereby enhancing SAZs-mediated hydroxyl radical (·OH) production, which subsequently leads to mitochondrial damage and intolerance to chemotherapy drug. We used the HGC27/DDP cell line for in vitro and in vivo experiments. The results showed that CSD achieved good therapeutic benefits, without any side effects such as inflammatory reaction. This system can induce multiple antitumor effect with H2O2 self-supply, mitochondrial damage, and ATP downregulation and eventually lead to chemosensitization.

Antioxidative myricetin-enriched nanoparticles towards acute liver injury

Acute liver injury (ALI) could severely destroy the liver function and cause inevitable damage to human health. Studies have demonstrated that excessive reactive oxygen species (ROS) and accompanying inflammatory factors play vital roles in the ALI disease. Herein, we fabricated a kind of nature-inspired myricetin-enriched nanomaterial via Michael addition and Schiff base reaction, which possessed uniform morphology, tunable component ratios, great stabilities, promising free radical scavenging abilities, biocompatibility and protective effects towards cells under oxidative stress. Additionally, the therapeutic effects were demonstrated using an ALI model by down-regulating ROS and inflammatory levels and restoring the liver function. This study could provide a strategy to construct robust and antioxidative nanomaterials using naturally occurring molecules against intractable diseases.

Paradoxical role of reactive oxygen species in bone remodelling: implications in osteoporosis and possible nanotherapeutic interventions

Osteoporosis is a metabolic bone disorder that affects both sexes and is the most common cause of fractures. Osteoporosis therapies primarily inhibit osteoclast activity, and are seldom designed to trigger new bone growth thereby frequently causing severe systemic adverse effects. Physiologically, the intracellular redox state depends on the ratio of pro-oxidants, oxidizing agents (reactive oxygen species, ROS) and antioxidants. ROS is the key contributor to oxidative stress in osteoporosis as changes in redox state are responsible for dynamic bone remodeling and bone regeneration. Imbalances in ROS generation vs. antioxidant systems play a pivotal role in pathogenesis of osteoporosis, stimulating osteoblasts and osteocytes towards osteoclastogenesis. ROS prevents mineralization and osteogenesis, causing increased turnover of bone loss. Alternatively, antioxidants either directly or indirectly, contribute to activation of osteoblasts leading to differentiation and mineralization, thereby reducing osteoclastogenesis. Owing to the unpredictability of immune responsiveness and reported adverse effects, despite promising outcomes from drugs against oxidative stress, treatment in clinics targeting osteoclast has been limited. Nanotechnology-mediated interventions have gained remarkable superiority over other treatment modalities in regenerative medicine. Nanotherapeutic approaches exploit the antioxidant properties of nanoparticles for targeted drug delivery to trigger bone repair, by enhancing their osteogenic and anti-osteoclastogenic potentials to influence the biocompatibility, mechanical properties and osteoinductivity. Therefore, exploiting nanotherapeutics for maintaining the differentiation and proliferation of osteoblasts and osteoclasts is quintessential.

A novel dual MoS2/FeGA quantum dots endowed injectable hydrogel for efficient photothermal and boosting chemodynamic therapy

Due to its responsiveness to the tumour microenvironment (TME), chemodynamic therapy (CDT) based on the Fenton reaction to produce cytotoxic reactive oxygen species (ROS) to destroy tumor has drawn more interest. However, the Fenton's reaction potential for therapeutic use is constrained by its modest efficacy. Here, we develop a novel injectable hydrogel system (FMH) on the basis of FeGA/MoS2 dual quantum dots (QDs), which uses near-infrared (NIR) laser in order to trigger the synergistic catalysis and photothermal effect of FeGA/MoS2 for improving the efficiency of the Fenton reaction. Mo4+ in MoS2 QDs can accelerate the conversion of Fe3+ to Fe2+, thereby promoting the efficiency of Fenton reaction, and benefiting from the synergistically enhanced CDT/PTT, FMH combined with NIR has achieved good anti-tumour effects in vitro and in vivo experiments. Furthermore, the quantum dots are easily metabolized after treatment because of their ultrasmall size, without causing any side effects. This is the first report to study the co-catalytic effect of MoS2 and Fe3+ at the quantum dot level, as well as obtain a good PTT/CDT synergy, which have implications for future anticancer research.

Cu-Hemin Nanosheets and Indocyanine Green Co-Loaded Hydrogel for Photothermal Therapy and Amplified Photodynamic Therapy

Near-infrared (NIR) organic small molecule indocyanine green (ICG) could respond well to 808 nm laser to promote local high temperature and ROS generation for realizing photothermal therapy (PTT)/photodynamic therapy (PDT). However, the high content of GSH in the tumor microenvironment (TME) limited the further therapeutic performance of ICG. Herein, injectable agarose in situ forming NIR-responsive hydrogels (CIH) incorporating Cu-Hemin and ICG were prepared for the first time. When CIH system was located to the tumor tissue through local injection, the ICG in the hydrogel could efficiently convert the light energy emitted by the 808 nm laser into thermal energy, resulting in the heating and softening of the hydrogel matrix, which releases the Cu-Hemin. Then, the over-expressed GSH in the TME could also down-regulated by Cu-Hemin, which amplified ICG-mediated PDT. In vivo experiments validated that ICG-based PDT/PTT and Cu-Hemin-mediated glutathione depletion could eliminate cancer tissues with admirable safety. This hydrogel-based GSH-depletion strategy is instructive to improve the objective response rate of PDT.