Cascade enzymes within self-assembled hybrid nanogel mimicked neutrophil lysosomes for singlet oxygen elevated cancer therapy

Nanomaterial-based regulation of redox metabolism for enhancing cancer therapy

Altered redox metabolism is one of the hallmarks of tumor cells, which not only contributes to tumor proliferation, metastasis, and immune evasion, but also has great relevance to therapeutic resistance. Therefore, regulation of redox metabolism of tumor cells has been proposed as an attractive therapeutic strategy to inhibit tumor growth and reverse therapeutic resistance. In this respect, nanomedicines have exhibited significant therapeutic advantages as intensively reported in recent studies. In this review, we would like to summarize the latest advances in nanomaterial-assisted strategies for redox metabolic regulation therapy, with a focus on the regulation of redox metabolism-related metabolite levels, enzyme activity, and signaling pathways. In the end, future expectations and challenges of such emerging strategies have been discussed, hoping to enlighten and promote their further development for meeting the various demands of advanced cancer therapies. It is highly expected that these therapeutic strategies based on redox metabolism regulation will play a more important role in the field of nanomedicine.

Metal ion interference therapy: metal-based nanomaterial-mediated mechanisms and strategies to boost intracellular "ion overload" for cancer treatment

Metal ion interference therapy (MIIT) has emerged as a promising approach in the field of nanomedicine for combatting cancer. With advancements in nanotechnology and tumor targeting-related strategies, sophisticated nanoplatforms have emerged to facilitate efficient MIIT in xenografted mouse models. However, the diverse range of metal ions and the intricacies of cellular metabolism have presented challenges in fully understanding this therapeutic approach, thereby impeding its progress. Thus, to address these issues, various amplification strategies focusing on ionic homeostasis and cancer cell metabolism have been devised to enhance MIIT efficacy. In this review, the remarkable progress in Fe, Cu, Ca, and Zn ion interference nanomedicines and understanding their intrinsic mechanism is summarized with particular emphasis on the types of amplification strategies employed to strengthen MIIT. The aim is to inspire an in-depth understanding of MIIT and provide guidance and ideas for the construction of more powerful nanoplatforms. Finally, the related challenges and prospects of this emerging treatment are discussed to pave the way for the next generation of cancer treatments and achieve the desired efficacy in patients.

Axial O Atom-Modulated Fe(III)-N4 Sites for Enhanced Cascade Catalytic 1O2-Induced Tumor Therapy

The rational construction of efficient hypoxia-tolerant nanocatalysts capable of generating singlet oxygen (1O2) without external stimuli is of great importance for tumor therapy. Herein, uniformly dispersed and favorable biosafety profile graphitic carbon nitride quantum dots immobilized with Fe-N4 moieties modulated by axial O atom (denoted as O-Fe-N4) are developed for converting H2O2 into 1O2 via Russell reaction, without introducing external energy. Notably, O-Fe-N4 performs two interconnected catalytic properties: glutathione oxidase-mimic activity to provide substrate for subsequent 1O2 generation, avoiding the blunting anticancer efficacy by glutathione. The O-Fe-N4 catalyst demonstrates a specific activity of 79.58 U mg-1 at pH 6.2, outperforming the most reported Fe-N4 catalysts. Density functional theory calculations demonstrate that the axial O atom can effectively modulate the relative position and electron affinity between Fe and N, lowering the activation energy, strengthening the selectivity, and thus facilitating the Russell-type reaction. The gratifying enzymatic activity stemming from the well-defined Fe-N/O structure can inhibit tumor proliferation by efficiently downregulating glutathione peroxidase 4 activity and inducing lipid peroxidation. Altogether, the O-Fe-N4 catalyst not only represents an efficient platform for self-cascaded catalysis to address the limitations of 1O2-involved cancer treatment but also provides a paradigm to enhance the performance of the Fe-N4 catalyst.

Current knowledge of hybrid nanoplatforms composed of exosomes and organic/inorganic nanoparticles for disease treatment and cell/tissue imaging

Exosome-nanoparticle hybrid nanoplatforms, can be prepared by combining exosomes with different types of nanoparticles. The main purpose of combining exosomes with nanoparticles is to overcome the limitations of using each of them as drug delivery systems. Using nanoparticles for drug delivery has some limitations, such as high immunogenicity, poor cellular uptake, low biocompatibility, cytotoxicity, low stability, and rapid clearance by immune cells. However, using exosomes as drug delivery systems also has its own drawbacks, such as poor encapsulation efficiency, low production yield, and the inability to load large molecules. These limitations can be addressed by utilizing hybrid nanoplatforms. Additionally, the use of exosomes allows for targeted delivery within the hybrid system. Exosome-inorganic/organic hybrid nanoparticles may be used for both therapy and diagnosis in the future. This may lead to the development of personalized medicine using hybrid nanoparticles. However, there are a few challenges associated with this. Surface modifications, adding functional groups, surface charge adjustments, and preparing nanoparticles with the desired size are crucial to the possibility of preparing exosome-nanoparticle hybrids. Additional challenges for the successful implementation of hybrid platforms in medical treatments and diagnostics include scaling up the manufacturing process and ensuring consistent quality and reproducibility across various batches. This review focuses on various types of exosome-nanoparticle hybrid systems and also discusses the preparation and loading methods for these hybrid nanoplatforms. Furthermore, the potential applications of these hybrid nanocarriers in drug/gene delivery, disease treatment and diagnosis, and cell/tissue imaging are explained.

Enzyme-Dynamic Extracellular Vesicles for Metalloimmunotherapy of Malignant Pleural Effusions

Malignant pleural effusions (MPEs) are hard to treat, and their onset usually signals terminal cancer. Immunotherapies hold promise but must overcome the immunosuppressive MPE microenvironment. Herein, we treat MPEs via synergistically combining two emerging cancer therapy modalities: enzyme-dynamic therapy (EDT) and metalloimmunotherapy. To do so, a nanoplatform termed "A-R-SOME" was developed which comprises MPE-targeted M1 type extracellular vesicles (EVs) loaded with (1) a manganese-based superoxide dismutase (SOD) enzyme, (2) stimulator of interferon genes (STING) agonist diABZI-2, and (3) signal transducer and an activator of transcription 3 (STAT3) small interfering RNA. Endogenous reactive oxygen species within tumors induced immunogenic cell death by EDT, along with STING activation by both Mn and diABZI-2, and suppression of the STAT3 pathway. Systemically administered A-R-SOME alleviated the MPE immunosuppressive microenvironment, triggered antitumor systemic immunity, and long-term immune memory, leading to the complete eradication of MPE and pleural tumors with 100% survival rate in an aggressive murine model. A-R-SOME-induced immune effects were also observed in human patient-derived MPE, pointing toward the translation potential of A-R-SOME as an experimental malignancy treatment.

A Photoactivated Self-Assembled Nanoreactor for Inducing Cascade-Amplified Oxidative Stress toward Type I Photodynamic Therapy in Hypoxic Tumors

Type I photodynamic therapy (PDT) generates reactive oxygen species (ROS) through oxygen-independent photoreactions, making it a promising method for treating hypoxic tumors. However, the superoxide anion (O2∙-) generated usually exhibits a low oxidation capacity, restricting the antitumor efficacy of PDT in clinical practice. Herein, a photoactivated self-assembled nanoreactor (1-NBS@CeO2) is designed through integration of type I PDT and cerium oxide (CeO2) nanozymes for inducing cascade-amplified oxidative stress in hypoxic tumors. The nanoreactor is constructed though co-assembly of an amphiphilic peptide (1-NBS) and CeO2, giving well-dispersed spherical nanoparticles with enhanced superoxide dismutase (SOD)-like and peroxidase (POD)-like activities. Following light irradiation, 1-NBS@CeO2 undergoes type I photoreactions to generated O2∙-, which is further catalyzed by the nanoreactors, ultimately forming hypertoxic hydroxyl radical (∙OH) through cascade-amplified reactions. The PDT treatment using 1-NBS@CeO2 results in elevation of intracellular ROS and depletion of GSH content in A375 cells, thereby inducing mitochondrial dysfunction and triggering apoptosis and ferroptosis of tumor cells. Importantly, intravenous administration of 1-NBS@CeO2 alongside light irradiation showcases enhances antitumor efficacy and satisfactory biocompatibility in vivo. Together, the self-assembled nanoreactor facilitates cascade-amplified photoreactions for achieving efficacious type I PDT, which holds great promise in developing therapeutic modules towards hypoxic tumors.

Opportunities for nanomaterials in enzyme therapy

In recent years, enzyme therapy strategies have rapidly evolved to catalyze essential biochemical reactions with therapeutic potential. These approaches hold particular promise in addressing rare genetic disorders, cancer treatment, neurodegenerative conditions, wound healing, inflammation management, and infectious disease control, among others. There are several primary reasons for the utilization of enzymes as therapeutics: their substrate specificity, their biological compatibility, and their ability to generate a high number of product molecules per enzyme unit. These features have encouraged their application in enzyme replacement therapy where the enzyme serves as the therapeutic agent to rectify abnormal metabolic and physiological processes, enzyme prodrug therapy where the enzyme initiates a clinical effect by activating prodrugs, and enzyme dynamic or starving therapy where the enzyme acts upon host substrate molecules. Currently, there are >20 commercialized products based on therapeutic enzymes, but approval rates are considerably lower than other biologicals. This has stimulated nanobiotechnology in the last years to develop nanoparticle-based solutions that integrate therapeutic enzymes. This approach aims to enhance stability, prevent rapid clearance, reduce immunogenicity, and even enable spatio-temporal activation of the therapeutic catalyst. This comprehensive review delves into emerging trends in the application of therapeutic enzymes, with a particular emphasis on the synergistic opportunities presented by incorporating enzymes into nanomaterials. Such integration holds the promise of enhancing existing therapies or even paving the way for innovative nanotherapeutic approaches.

Neutrophil-Mimicking Nanozyme with Cascade Catalytic Releasing Nitric Oxide and Signet Oxygen Property for Synergistic Bimodal Therapy of Methicillin-Resistant Staphylococcus Aureus Infections

Recently, chloroperoxidase (CPO)-mediated enzyme dynamic therapy (EDT) by mimicking the antipathogen function of neutrophils via generating highly active signet oxygen (1O2) has attracted great interest in biomedical applications. However, the therapeutic efficiency of EDT is largely restricted by the low CPO delivery efficiency and insufficient hydrogen peroxide (H2O2) supply. In the present work, a neutrophil-mimicking nanozyme of MGBC with high CPO delivery efficiency, H2O2 self-supply, and enzyme-cascade catalytic properties is designed for high-efficient treatment of methicillin-resistant Staphylococcus aureus (MRSA) infections. In the infection microenvironment, MGBC can effectively catalyze glucose to self-supply substantial H2O2, which enables long-lasting 1O2 generation via the CPO-mediated catalytic reaction. At the meantime, MGBC can also catalyze H2O2 to sustainably release NO for gas therapy (GT), which synergistically strengthens the therapeutic effect of EDT. As a result, MGBC displayed effective MRSA-killing and MSRA biofilms-eradicating properties, and high efficiency in treating both MRSA infected full-thickness excision wounds and subcutaneous MRSA infection by exerting the synergistic bimodal EDT/GT therapeutic effects. In-depth mechanism study revealed that the synergistic EDT/GT antibacterial effects of MGBC can attenuate the drug resistance and toxicity of MRSA by significantly downregulating quorum sensing, multidrug efflux, virulence, and biofilm formation-related genes.

Increasing Multienzyme Cascade Efficiency and Stability of MOF via Partitioning Immobilization

Enhancing the stability of multienzyme cascade reactions in metal-organic frameworks (MOFs) is a challenging task in the fields of biotechnology and chemistry. However, addressing this challenge could yield far-reaching benefits across the application range in the biomedical, food, and environmental sectors. In this study, multienzyme partitioning immobilization that sequentially immobilizes cascade enzymes with hierarchical MOFs is proposed to reduce substrate diffusion resistance. Conversion results of ginsenosides indicate that this strategy improves the cascade efficiency up to 1.26 times. The substrate diffusion model is used to investigate the dual-interenzyme mass transfer behavior of substrates in the restricted domain space and evaluate the substrate channeling effect under partitioning immobilization. Molecular docking and kinetic simulations reveal that the MOFs effectively limit the conformational changes of cascade enzymes at high temperatures and in organic solvents while maintaining a large pocket of active centers. This phenomenon increased efficient substrate docking to the enzyme molecules, further optimizing cascade efficiency. The results of the immobilization of GOX and horseradish peroxidase as model enzymes indicate that the partitioned MOF immobilization strategy could be used for universal adaptation of cascade enzymes.

Immobilized Multi-Enzyme/Nanozyme Biomimetic Cascade Catalysis for Biosensing Applications

Multiple enzyme-induced cascade catalysis has an indispensable role in the process of complex life activities, and is widely used to construct robust biosensors for analyzing various targets. The immobilized multi-enzyme cascade catalysis system is a novel biomimetic catalysis strategy that immobilizes various enzymes with different functions in stable carriers to simulate the synergistic catalysis of multiple enzymes in biological systems, which enables high stability of enzymes and efficiency enzymatic cascade catalysis. Nanozymes, a type of nanomaterial with intrinsic enzyme-like characteristics and excellent stabilities, are also widely applied instead of enzymes to construct immobilized cascade systems, achieving better catalytic performance and reaction stability. Due to good stability, reusability, and remarkably high efficiency, the immobilized multi-enzyme/nanozyme biomimetic cascade catalysis systems show distinct advantages in promoting signal transduction and amplification, thereby attracting vast research interest in biosensing applications. This review focuses on the research progress of the immobilized multi-enzyme/nanozyme biomimetic cascade catalysis systems in recent years. The construction approaches, factors affecting the efficiency, and applications for sensitive biosensing are discussed in detail. Further, their challenges and outlooks for future study are also provided.

Dual Enzyme-Encapsulated Materials for Biological Cascade Chemistry and Synergistic Tumor Starvation

Framework and polymeric nanoreactors (NRs) have distinct advantages in improving chemical reaction efficiency in the tumor microenvironment (TME). Nanoreactor-loaded oxidoreductase enzyme is activated by tumor acidity to produce H2O2 by increasing tumor oxidative stress. High levels of H2O2 induce self-destruction of the vesicles by releasing quinone methide to deplete glutathione and suppress the antioxidant potential of cancer cells. Therefore, the synergistic effect of the enzyme-loaded nanoreactors results in efficient tumor ablation via suppressing cancer-cell metabolism. The main driving force would be to take advantage of the distinct metabolic properties of cancer cells along with the high peroxidase-like activity of metalloenzyme/metalloprotein. A cascade strategy of dual enzymes such as glucose oxidase (GOx) and nitroreductase (NTR) wherein the former acts as an O2-consuming agent such as overexpression of NTR and further amplified NTR-catalyzed release for antitumor therapy. The design of cascade bioreductive hypoxia-responsive drug delivery via GOx regulates NTR upregulation and NTR-responsive nanoparticles. Herein, we discuss tumor hypoxia, reactive oxygen species (ROS) formation, and the effectiveness of these therapies. Nanoclusters in cascaded enzymes along with chemo-radiotherapy with synergistic therapy are illustrated. Finally, we outline the role of the nanoreactor strategy of cascading enzymes along with self-synergistic tumor therapy.

Multifunctional Cu2Se/F127 Hydrogel with SOD-Like Enzyme Activity for Efficient Wound Healing

Free radicals are secreted following skin damage and cause oxidative stress and inflammatory reactions that increase the difficulty of wound healing. In this study, copper-based nanozyme Cu2Se nanosheets (NSs) are synthesized by an anion-exchange strategy and apply to wounds with F127 hydrogels to investigate the healing effect of this nanozyme composite hydrogels on wounds. Cu2Se NSs have a large number of catalytically active centers, are simple to synthesize, require few reaction conditions and have a short synthesis cycle. In vitro experiments have shown that Cu2Se NSs possess superoxide dismutase (SOD)-like activity and nitrogen radical scavenging activity and promote angiogenesis and fibroblast migration. The doping of Cu2Se NSs into the F127 hydrogel does not have a significantly affect on the properties of the hydrogel. This hybridized hydrogel not only adapts to the irregular and complex morphology of acute wounds but also prolongs the duration of nanozyme action on the wound, thus promoting wound healing. Transcriptomic analysis further reveals the potential therapeutic mechanism of the Cu2Se/F127 hydrogel in promoting acute wound healing. Animal experiments have shown that the Cu2Se/F127 hydrogel has good biosafety. The Cu2Se/F127 hydrogel provides an innovative idea for the development of hydrogel dressings for the treatment of acute wounds.

Dual-enzyme decorated semiconducting polymer nanoagents for second near-infrared photoactivatable ferroptosis-immunotherapy

Enzymes provide a class of potential options to treat cancer, while the precise regulation of enzyme activities for effective and safe therapeutic actions has been poorly reported. Dual-enzyme decorated semiconducting polymer nanoagents for second near-infrared (NIR-II) photoactivatable ferroptosis-immunotherapy are reported in this study. Such nanoagents (termed SPHGA) consist of hemoglobin (Hb)-based semiconducting polymer (SP@Hb), adenosine deaminase (ADA) and glucose oxidase (GOx) with loadings in a thermal-responsive nanoparticle shell. NIR-II photoactivation of SPHGA results in the generation of heat to trigger on-demand releases of two enzymes (ADA and GOx) via destroying the thermal-responsive nanoparticle shells. In the tumor microenvironment, GOx oxidizes glucose to form hydrogen peroxide (H2O2), which promotes the Fenton reaction of iron in SP@Hb, resulting in an enhanced ferroptosis effect and immunogenic cell death (ICD). In addition, ADA degrades high-level adenosine to reverse the immunosuppressive microenvironment, thus amplifying antitumor immune responses. Via NIR-II photoactivatable ferroptosis-immunotherapy, SPHGA shows an improved effect to absolutely remove bilateral tumors and effectively suppress tumor metastases in subcutaneous 4T1 breast cancer models. This study presents a dual-enzyme-based nanoagent with controllable therapeutic actions for effective and precise cancer therapy.

Development and evaluation of a pH-responsive Mimosa pudica seed mucilage/β- cyclodextrin-co-poly(methacrylate) hydrogel for controlled drug delivery: In vitro and in vivo assessment

In this comprehensive investigation, a novel pH-responsive hydrogel system comprising mimosa seed mucilage (MSM), β-cyclodextrin (β-CD), and methacrylic acid (MAA) was developed via free radical polymerization technique to promote controlled drug delivery. The hydrogel synthesis involved strategic variations in polymer, monomer, and crosslinker content in fine-tuning its drug-release properties. The resultant hydrogel exhibited remarkable pH sensitivity, selectively liberating the model drug (Capecitabine = CAP) under basic conditions while significantly reducing release in an acidic environment. Morphological, thermal, and structural analyses proved that CAP has a porous texture, high stability, and an amorphous nature. In vitro drug release experiments showcased a sustained and controlled release profile. Optimum release (85.33 %) results were recorded over 24 h at pH 7.4 in the case of MMB9. Pharmacokinetic evaluation in healthy male rabbits confirmed bioavailability enhancement and sustained release capabilities. Furthermore, rigorous toxicity evaluations and histopathological analyses ensured the safety and biocompatibility of the hydrogel. This pH-triggered drug delivery system can be a promising carrier system for drugs involving frequent administrations.

Engineering and Targeting Neutrophils for Cancer Therapy

Neutrophils are the most abundant white blood cells in the circulation and act as the first line of defense against infections. Increasing evidence suggests that neutrophils possess heterogeneous phenotypes and functional plasticity in human health and diseases, including cancer. Neutrophils play multifaceted roles in cancer development and progression, and an N1/N2 paradigm of neutrophils in cancer is proposed, where N1 neutrophils exert anti-tumor properties while N2 neutrophils display tumor-supportive and immune-suppressive functions. Selective activation of beneficial neutrophil population and targeted inhibition or re-polarization of tumor-promoting neutrophils has shown an important potential in tumor therapy. In addition, due to the natural inflammation-responsive and physical barrier-crossing abilities, neutrophils and their derivatives (membranes and extracellular vesicles (EVs)) are regarded as advanced drug delivery carriers for enhanced tumor targeting and improved therapeutic efficacy. In this review, the recent advances in engineering neutrophils for drug delivery and targeting neutrophils for remodeling tumor microenvironment (TME) are comprehensively presented. This review will provide a broad understanding of the potential of neutrophils in cancer therapy.

Manganese-Doped Potassium Chloride Nanoelectrodes to Potentiate Electrochemical Immunotherapy

Hypochlorous acid (HClO), as a powerful oxidizer, is obtained from the oxidation of Cl- ions during the electrochemical therapy (EChT) process for cancer therapy. However, the extracellular generated HClO is inadequate to inhibit effective tumor cell death. Herein, manganese-doped potassium chloride nanocubes (MPC NCs) fabricated and modified with amphipathic polymer PEG (PMPC NCs) to function as massive three-dimensional nanoelectrodes (NEs) were developed to enhance the generation of HClO for electrochemical immunotherapy under an alternating electric field. Under an square-wave alternating current (AC) electric field, the generation of HClO was boosted by PMPC NEs due to the enlarged active surface area, enhanced mass transfer rate, and improved electrocatalytic activity. Notably, PMPC NEs upregulated the intracellular HClO concentration to induce robust immunogenic cell death (ICD) under an AC electric field. Meanwhile, the electric-triggered release of Mn2+ effectively stimulated dendritic cells (DCs) maturation. In vivo results illustrated that PMPC-mediated EChT inhibited tumor growth and triggered the promotion of the immune response to regulate the tumor immune microenvironment. Based on the potent antitumor immunity, PMPC-mediated EChT was further combined with an immune checkpoint inhibitor (αCTLA-4) to realize combined EChT-immunotherapy, which demonstrated enhanced tumor inhibition of the primary tumors and an abscopal effect on distant tumors. To summarize, our work highlights the application of electrochemical-immunotherapy technology in tumor therapy.

Nanomaterial-mediated modulation of the cGAS-STING signaling pathway for enhanced cancer immunotherapy

Despite the current promise of immunotherapy, many cancer patients still suffer from challenges such as poor immune response rates, resulting in unsatisfactory clinical efficacy of existing therapies. There is an urgent need to combine emerging biomedical discoveries and innovations in traditional therapies. Modulation of the cGAS-STING signalling pathway represents an important innate immunotherapy pathway that serves as a crucial DNA sensing mechanism in innate immunity and viral defense. It has attracted increasing attention as an emerging target for cancer therapy. The recent advancements in nanotechnology have led to the significant utilization of nanomaterials in cancer immunotherapy, owing to their exceptional physicochemical properties such as large specific surface area and efficient permeability. Given the rapid development of cancer immunotherapy driven by the cGAS-STING activation, this study reviews the latest research progress in employing nanomaterials to modulate this signaling pathway. Based on the introduction of the main activation mechanisms of cGAS-STING pathway, this review focuses on nanomaterials that mediate the agonists involved and effectively activate this signaling pathway. In addition, combination nanotherapeutics based on the activation of the cGAS-STING signaling pathway are also discussed, including emerging strategies combining nanoformulated agonists with chemotherapy, radiotherapy as well as other immunomodulation in tumor targeting therapy. STATEMENT OF SIGNIFICANCE: Given the rapid development of cancer immunotherapy driven by the cGAS / STING activation, this study reviews the latest research advances in the use of nanomaterials to modulate this signaling pathway. Based on the introduction of key cGAS-STING components and their activation mechanisms, this review focuses on nanomaterials that can mediate the corresponding agonists and effectively activate this signaling pathway. In addition, combination nanotherapies based on the activation of the cGAS-STING signaling pathway are also discussed, including emerging strategies combining nanoformulated agonists with chemotherapy, radiotherapy as well as immunomodulation in cancer therapy,.

Ultrasmall metal alloy nanozymes mimicking neutrophil enzymatic cascades for tumor catalytic therapy

Developing strategies that emulate the killing mechanism of neutrophils, which involves the enzymatic cascade of superoxide dismutase (SOD) and myeloperoxidase (MPO), shows potential as a viable approach for cancer therapy. Nonetheless, utilizing natural enzymes as therapeutics is hindered by various challenges. While nanozymes have emerged for cancer treatment, developing SOD-MPO cascade in one nanozyme remains a challenge. Here, we develop nanozymes possessing both SOD- and MPO-like activities through alloying Au and Pd, which exhibits the highest cascade activity when the ratio of Au and Pd is 1:3, attributing to the high d-band center and adsorption energy for superoxide anions, as determined through theoretical calculations. The Au1Pd3 alloy nanozymes exhibit excellent tumor therapeutic performance and safety in female tumor-bearing mice, with safety attributed to their tumor-specific killing ability and renal clearance ability caused by ultrasmall size. Together, this work develops ultrasmall AuPd alloy nanozymes that mimic neutrophil enzymatic cascades for catalytic treatment of tumors.

Mild hyperthermia-assisted chitosan hydrogel with photothermal antibacterial property and CAT-like activity for infected wound healing

Infected wounds pose a serious threat to public health and pose a significant challenge and financial burden worldwide. The treatment of infected wounds is now an urgent problem to be solved. Herein, mild hyperthermia-assisted hydrogels composed of carboxymethyl chitosan (CMCs), oxidized dextran (Odex), epigallocatechin gallate (EGCG) and PtNPs@PVP (CAT-like nanoenzymes) were proposed for the repair of infected wounds. The incorporation of PtNPs@PVP nanoenzymes give the hydrogels excellent photothermal property and CAT-like activity. When the temperature is maintained at 42-45 °C under 808 nm near infrared (NIR) exposure, the CMCs/Odex/EGCG/Nanoenzymes (COEN2) hydrogel demonstrated highly enhanced antibacterial ability (95.9 % in vivo), hydrogen peroxide (H2O2) scavenging ratio (85.1 % in vitro) and oxygen supply (20.7 mg/L in vitro). Furthermore, this mild-heat stimulation also promoted angiogenesis in the damaged skin area. Overall, this multifunctional hydrogel with antibacterial, antioxidant, oxygen supply, hemostasis, and angiogenesis capabilities has shown great promise in the repair of infected wounds. This study establishes the paradigm of enhanced infected wound healing by mild hyperthermia-assisted H2O2 scavenging, oxygen supplemental, and photothermal antibacterial hydrogels.

Quince seed mucilage/β-cyclodextrin/Mmt-Na+-co-poly (methacrylate) based pH-sensitive polymeric carriers for controlled delivery of Capecitabine

In current work, quince seed mucilage and β-Cyclodextrin based pH regulated hydrogels were developed using aqueous free radical polymerization to sustain Capecitabine release patterns and to overcome its drawbacks, such as high dose frequency, short half-life, and low bioavailability. Developed networks were subjected to thermal analysis, Fourier transforms infrared spectroscopy, powder x-ray diffraction, elemental analysis, scanning electron microscopy, equilibrium swelling, and in-vitro release investigations to assess the network system's stability, complexation, morphology, and pH responsiveness. Thermally stable pH-responsive cross-linked networks were formed. Nanocomposite hydrogels were prepared by incorporating Capecitabine-containing clay into the swollen hydrogels. All the formulations exhibited equilibrium swelling ranging from 67.98 % to 92.98 % at pH 7.4. Optimum Capecitabine loading (88.17 %) was noted in the case of hydrogels, while it was 74.27 % in nanocomposite hydrogels. Excellent gel content (65.88 %-93.56 %) was noticed among developed formulations. Elemental analysis ensured the successful incorporation of Capecitabine. Nanocomposite hydrogels released 80.02 % longer than hydrogels after 30 h. NC hydrogels had higher t1/2 (10.57 h), AUC (121.52 μg.h/ml), and MRT (18.95 h) than hydrogels in oral pharmacokinetics. These findings imply that the pH-responsive carrier system may improve Capecitabine efficacy and reduce dosing frequency in cancer therapy. Toxicity profiling proved the system's safety, non-toxicity, and biocompatibility.

Chirality-Dependent Reprogramming of Macrophages by Chiral Nanozymes

It is known that extracellular free radical reactive oxygen species (ROS) rather than intracellular ROS plays a non-substitutable role in regulation of tumor-suppressing (M1) tumor-associated macrophages (TAMs) polarization. However, most therapeutic nanoplatforms mainly provide intracellular ROS and exhibit insufficient accumulation near TAMs, which strongly limits the macrophage-based immunotherapeutic effects. Here we design and synthesize chiral MoS2 /CoS2 nanozymes with peroxidase (POD)-like and catalase (CAT)-like activities to efficiently modulate TAMs polarization and reverse tumor immunosuppression by harnessing their chirality-specific interactions with biological systems. MoS2 /CoS2 nanoparticles coordinated with d-chirality (d-NPs, right-handed) show improved pharmacokinetics with longer circulating half-life and higher tumor accumulation compared with their l (left-handed)- and dl (racemate)-counterparts. Further, d-NPs can escape from macrophage uptake in the tumor microenvironment (TME) with the aid of cell-unpreferred opposite chirality and act as extracellular hydroxyl radicals (⋅OH) and oxygen (O2 ) generators to efficiently repolarize TAMs into M1 phenotype. On the contrary, l-NPs showed high cellular uptake due to chirality-driven homologous adhesion between l-NPs and macrophage membrane, leading to limited M1 polarization performance. As the first example for developing chiral nanozymes as extracellular-localized ROS generators to reprogram TAMs for cancer immunotherapy, this study opens an avenue for applications of chiral nanozymes in immunomodulation.

Preparation of lignin-based hydrogels, their properties and applications

Polymers obtained from biomass are a concerning alternative to petro-based polymers because of their low cost of manufacturing, biocompatibility, ecofriendly and biodegradability. Lignin as the second richest and the only polyaromatics bio-polymer in plant which has been most studied for the numerous applications in different fields. But, in the past decade, the exploitation of lignin for the preparation of new smart materials with improved properties has been broadly sought, because lignin valorization plays one of the primary challenging issues of the pulp and paper industry and lignocellulosic biorefinery. Although, well suited chemical structure of lignin comprises of many functional hydrophilic and active groups, such as phenolic hydroxyls, carboxyls and methoxyls, which provides a great potential to be applied in the preparation of biodegradable hydrogels. In this review, lignin hydrogel is covered with preparation strategies, properties and applications. This review reports some important properties, such as mechanical, adhesive, self-healing, conductive, antibacterial and antifreezing properties were then discussed. Furthermore, herein also reviewed the current applications of lignin hydrogel, including dye adsorption, smart materials for stimuli sensitive, wearable electronics for biomedical applications and flexible supercapacitors. Overall, this review covers recent progresses regarding lignin-based hydrogel and constitutes a timely review of this promising material.

A neutrophil mimicking metal-porphyrin-based nanodevice loaded with porcine pancreatic elastase for cancer therapy

Precise discrimination and eradication of cancer cells by immune cells independent of antigen recognition is promising for solid tumor therapeutics, yet remains a tremendous challenge. Inspired by neutrophils, here we design and construct a tumor discrimination nanodevice based on the differential histone H1 isoform expression. In this nanodevice, neutrophil membrane camouflage and glutathione (GSH)-unlocking effect on Fe-porphyrin metal-organic framework structure ensures selectivity to cancer cells. The released porcine pancreatic elastase (PPE) simulates neutrophils' action to induce histone H1 release-dependent selective cancer cell killing. Meanwhile, nuclear localization signal (NLS) peptide-tagged porphyrin (porphyrin-NLS) acts as in-situ singlet oxygen (¹O₂) generator to amplify histone H1 nucleo-cytoplasmic translocation by inducing DNA double-strand breaks (DSBs) under laser irradiation, further promoting elimination of cancer cells. The overexpressed histone H1 isoform in cancer cells improves selectivity of our nanodevice to cancer cells. In vivo studies demonstrate that our design can not only inhibit primary tumor growth, but also induce adaptive T-cell response-mediated abscopal effect to against distal tumors.

An Updated Review on Advances in Hydrogel-Based Nanoparticles for Liver Cancer Treatment

More than 90% of all liver malignancies are hepatocellular carcinomas (HCCs), for which chemotherapy and immunotherapy are the ideal therapeutic choices. Hepatocellular carcinoma is descended from other liver diseases, such as viral hepatitis, alcoholism, and metabolic syndrome. Normal cells and tissues may suffer damage from common forms of chemotherapy. In contrast to systemic chemotherapy, localized chemotherapy can reduce side effects by delivering a steady stream of chemotherapeutic drugs directly to the tumor site. This highlights the significance of controlled-release biodegradable hydrogels as drug delivery methods for chemotherapeutics. This review discusses using hydrogels as drug delivery systems for HCC and covers thermosensitive, pH-sensitive, photosensitive, dual-sensitive, and glutathione-responsive hydrogels. Compared to conventional systemic chemotherapy, hydrogel-based drug delivery methods are more effective in treating cancer.

Customizable Low-Friction Tough Hydrogels for Potential Cartilage Tissue Engineering by a Rapid Orthogonal Photoreactive 3D-Printing Design

Hydrogels have demonstrated wide applications in tissue engineering, but it is still challenging to develop strong, customizable, low-friction artificial scaffolds. Here, we report a rapid orthogonal photoreactive 3D-printing (ROP3P) strategy to achieve the design of high-performance hydrogels in tens of minutes. The orthogonal ruthenium chemistry enables the formation of multinetworks in hydrogels via phenol-coupling reaction and traditional radical polymerization. Further Ca²⁺-cross-linking treatment greatly improves their mechanical properties (6.4 MPa at a critical strain of 300%) and toughness (10.85 MJ m^-3). The tribological investigation reveals that the high elastic moduli of the as-prepared hydrogels improve their lubrication (∼0.02) and wear-resistance performances. These hydrogels are biocompatible and nontoxic and promote bone marrow mesenchymal stem cell adhesion and propagation. The introduction of 1-hydroxy-3-(acryloylamino)-1,1-propanediylbisphosphonic acid units can greatly enhance their antibacterial property to kill typical Escherichia coli and Staphylococcus aureus. Moreover, the rapid ROP3P can achieve hydrogel preparation in several seconds and is readily compatible with making artificial meniscus scaffolds. The printed meniscus-like materials are mechanically stable and can maintain their shape under long-term gliding tests. It is anticipated that these high-performance customizable low-friction tough hydrogels and the highly efficient ROP3P strategy could promote further development and practical applications of hydrogels in biomimetic tissue engineering, materials chemistry, bioelectronics, and so on.

Inflammatory Cell-Inspired Cascade Nanozyme Induces Intracellular Radical Storm for Enhanced Anticancer Therapy

Manipulating intracellular levels of reactive oxygen and nitrogen species (RONS) is of great potential for cancer treatment. Inspired by the natural mechanism of a radical storm in inflammatory cells via activated and regulatable biocatalysis, the authors herein report a self-powered nanozyme that can enable RONS production in tumor cells via cascade reactions. The nanozymes are constructed via glucose oxidase (GOx)-templated inverse microemulsion polymerization from acrylamide, arginine-acrylamide, ferrocene-acrylate, and N,N'-bis(acryloyl)cystamine, followed by surface coating with hyaluronic acid. After targeted delivery into cancer cells, the nanozymes are dissociated by intracellular glutathione to release GOx, which decomposed glucose to generate gluconic acid and H₂ O₂ . Under such acidified conditions, H₂ O₂ efficiently oxidized pendant arginine residues to produce nitric oxide , transformed into a highly toxic hydroxyl radical and superoxide anion via ferrocene-mediated Fenton reaction and Haber-Weiss cycle, and simultaneously generated peroxynitrite anion via reaction between NO and ·O₂ ^- , thus provoking the RONS radical storm to effectively eradicate A549 tumor cells both in vitro and in vivo. This nature-inspired enzyme-chemical dynamic therapy may provide a promising modality for anti-cancer treatment.

Confinement of Triple-Enzyme-Involved Antioxidant Cascade in Two-Dimensional Nanostructure

Application of antioxidant enzymes in medical or industrial processes is limited due to their high sensitivity to environmental conditions. Incorporation of such enzymes in nanostructures provides a promising route to obtain highly efficient and robust biocatalytic system to scavenge reactive oxygen species (ROS). Here, this question was addressed by confinement of superoxide dismutase (SOD), horseradish peroxidase (HRP), and catalase (CAT) enzymes into nanostructures containing polyelectrolyte building blocks (alginate (Alg) and trimethyl chitosan (TMC)) and delaminated layered double hydroxide (dLDH) nanoparticle support. The nanocomposite possessed excellent structural and colloidal stability, while antioxidant tests revealed that the enzymes remained active upon immobilization and the developed composite greatly reduced intracellular oxidative stress in two-dimensional cell cultures. Moreover, it effectively prevented hydrogen peroxide-induced double stranded DNA breaks, which is a common consequence of oxidative stress. The results provide important tools to design complex nanostructures with multienzymatic antioxidant activities for ROS scavenging.

Imine-Linked Covalent Organic Framework Modulates Oxidative Stress in Alzheimer's Disease

Oxidative stress due to Cu²⁺-triggered aggregation of β-amyloid protein (Aβ) and reactive oxygen species (ROS) overexpression in the brain is an important hallmark of early stages of Alzheimer's disease (AD) pathogenesis. The ideal modulator for improving the oxidative stress microenvironment in AD brains should take both Cu²⁺ and ROS into consideration, which has been rarely reported. Here, a combined therapeutic strategy was achieved by co-encapsulating superoxide dismutase (SOD) and catalase (CAT) in imine-linked covalent organic frameworks (COFs), which were modified with peptide KLVFF (T5). The nanocomposite SC@COF-T5 exhibited an oxidative stress eradicating ability through ROS elimination and Cu²⁺ chelation, combined with the inhibition of Aβ42 monomer aggregation and disaggregation of Aβ42 fibrils. In vivo experiments indicated that SC@COF-T5 with a high blood-brain barrier (BBB) penetration efficiency was effective to reduce Aβ deposition, expression of pro-inflammatory cytokines, ROS levels, and neurologic damage in AD model mice, consequently rescuing memory deficits of AD mice. This work not only confirms the feasibility and merits of the therapeutic strategy regarding multiple targets for treatment of early AD pathogenesis but also opens up a novel direction for imine-linked COFs in biomedical applications.

Carbon Dots-Based Nanozyme for Drug-Resistant Lung Cancer Therapy by Encapsulated Doxorubicin/siRNA Cocktail

Background

Nanomaterials exhibited intrinsic enzyme-like properties due to the unique properties compared with natural enzyme. Carbon dots (CDs) are an important kind of quantum-sized nanomaterials, which have enormous application potential in bio-imaging, drug carrier, and nanosystems. Carbon dots possess intrinsic enzyme-like properties, such as glutathione (GSH) oxidase or peroxidase activities.

Methods

A co-delivery nanosystem that could carry siRNA and doxorubucin (DOX) simultaneously has been studied in this work. The co-delivery based on carbon dots was surface-modified with poly-ethylenimine (PEI) and loaded the siMRP1 with chemotherapeutics on the surface with pH-triggered drug release. The CD-PEI was synthesized by one-step microwave assisted method; the PEI was raw materials and passivator during the reaction process that makes CDs exhibit excellent optical property.

Results

The CD-PEI was capable of loading and delivering siMRP1 and DOX to tumors and releasing them synchronously in cells in an acid-triggered manner. The particles exhibited GSH oxidase-like catalytic property, oxidizing GSH to oxidized glutathione with concomitant increase of reactive oxygen species (ROS). We found that silencing of MRP1 by co-delivery system antagonized chemoresistance by increasing DOX accumulation and significantly enhancing the inhibitory effect of cell viability induced by CD-PEI-DOX. The co-delivery system dramatically inhibited tumor growth in xenograft model, and CDs counteracted MRP1 function by siRNA-mediated knockdown of MRP1.

Conclusion

Taken together, we uncover the potential role of CDs with a combination of siRNA and chemotherapeutics in overcoming chemoresistance of lung cancer by suppressing MRP1 and oxidation of GSH. Our findings imply its potential of antagonizing chemoresistance to enhance therapeutic efficiency of doxorubicin in clinical practices of lung cancer treatment.

A self-crosslinking nanogel scaffold for enhanced catalytic efficiency and stability

We report a facile and efficient approach to prepare multifunctional bioinspired platforms under mild conditions that offer increased catalytic efficiency and stability.

Hydrogel systems for targeted cancer therapy

When hydrogel materials with excellent biocompatibility and biodegradability are used as excellent new drug carriers in the treatment of cancer, they confer the following three advantages. First, hydrogel materials can be used as a precise and controlled drug release systems, which can continuously and sequentially release chemotherapeutic drugs, radionuclides, immunosuppressants, hyperthermia agents, phototherapy agents and other substances and are widely used in the treatment of cancer through radiotherapy, chemotherapy, immunotherapy, hyperthermia, photodynamic therapy and photothermal therapy. Second, hydrogel materials have multiple sizes and multiple delivery routes, which can be targeted to different locations and types of cancer. This greatly improves the targeting of drugs, thereby reducing the dose of drugs and improving treatment effectiveness. Finally, hydrogel can intelligently respond to environmental changes according to internal and external environmental stimuli so that anti-cancer active substances can be remotely controlled and released on demand. Combining the abovementioned advantages, hydrogel materials have transformed into a hit in the field of cancer treatment, bringing hope to further increase the survival rate and quality of life of patients with cancer.

pH Responsive Hydrogels for the Delivery of Capecitabine: Development, Optimization and Pharmacokinetic Studies

The objective of the current study was to achieve a sustained release profile of capecitabine (CAP), an anticancer agent frequently administered in conventional dosage form due to its short plasma half-life. A drug-loaded smart pH responsive chitosan/fenugreek-g-poly (MAA) hydrogel was synthesized by an aqueous free radical polymerization technique. The developed network was evaluated for capecitabine loading %, swelling response, morphology, structural and compositional characteristics, and drug release behavior. Significantly higher swelling and in vitro drug release rate were exhibited by formulations at pH 7.4 than at pH 1.2, demonstrating the pH responsive character of hydrogels. Swelling percentage and CAP loading ranged within 74.45-83.54% and 50.13-72.43%, respectively. Maximum release, up to 93%, was demonstrated over 30 h, evidencing the controlled release pattern of CAP from hydrogels. The optimized formulation was further screened for acute oral toxicity studies. No signs of oral, dermal, or ocular toxicities were noticed, confirming safety evidence of the network. Furthermore, pharmacokinetic analysis demonstrated the sustained release response of CAP from hydrogels as confirmed by a significant increase in plasma half-life (t_1/2) (13 h) and AUC (42.88 µg h/mL) of CAP. Based on these findings, fabricated hydrogels are strongly recommended as a biocompatible carrier for colorectal delivery of active agents.

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.

Nanozymes for Regenerative Medicine

Nanozymes refer to nanomaterials that catalyze enzyme substrates into products under relevant physiological conditions following enzyme kinetics. Compared to natural enzymes, nanozymes possess the characteristics of higher stability, easier preparation, and lower cost. Importantly, nanozymes possess the magnetic, fluorescent, and electrical properties of nanomaterials, making them promising replacements for natural enzymes in industrial, biological, and medical fields. On account of the rapid development of nanozymes recently, their application potentials in regeneration medicine are gradually being explored. To highlight the achievements in the regeneration medicine field, this review summarizes the catalytic mechanism of four types of representative nanozymes. Then, the strategies to improve the biocompatibility of nanozymes are discussed. Importantly, this review covers the recent advances in nanozymes in tissue regeneration medicine including wound healing, nerve defect repair, bone regeneration, and cardiovascular disease treatment. In addition, challenges and prospects of nanozyme researches in regeneration medicine are summarized.

Multifunctional stimuli-responsive hybrid nanogels for cancer therapy: Current status and challenges

With cancer research shifting focus to achieving multifunctionality in cancer treatment strategies, hybrid nanogels are making a rapid rise to the spotlight as novel, multifunctional, stimuli-responsive, and biocompatible cancer therapeutic strategies. They can possess cancer cell-specific cytotoxic effects themselves, carry drugs or enzymes that can produce cytotoxic effects, improve imaging modalities, and target tumor cells over normal cells. Hybrid nanogels bring together a wide range of desirable properties for cancer treatment such as stimuli-responsiveness, efficient loading and protection of molecules such as drugs or enzymes, and effective crossing of cellular barriers among other properties. Despite their promising abilities, hybrid nanogels are still far from being used in the clinic, and their available data remains relatively limited. However, many studies can be done to facilitate this clinical transition. This review is critically summarizing and analyzing the recent information and progress on the use of hybrid nanogels particularly inorganic nanoparticle-based and organic nanoparticle-based hybrid nanogels in the field of oncology and future directions to aid in transferring those results to the clinic. This work concludes that the future of hybrid nanogels is greatly impacted by therapeutic and non-therapeutic factors. Therapeutic factors include the lack of hemocompatibility studies, acute and chronic toxicological studies, and information on agglomeration capability and extent, tumor heterogeneity, interaction with proteins in physiological fluids, endocytosis-exocytosis, and toxicity of the nanogels' breakdown products. Non-therapeutic factors include the lack of clear regulatory guidelines and standardized assays, limitations of animal models, and difficulties associated with good manufacture practices (GMP).

Multifaceted Elevation of ROS Generation for Effective Cancer Suppression

The in situ lactate oxidase (LOx) catalysis is highly efficient in reducing oxygen to H₂O₂ due to the abundant lactate substrate in the hypoxia tumor microenvironment. Dynamic therapy, including chemodynamic therapy (CDT), photodynamic therapy (PDT), and enzyme dynamic therapy (EDT), could generate reactive oxygen species (ROS) including ·OH and ¹O₂ through the disproportionate or cascade biocatalytic reaction of H₂O₂ in the tumor region. Here, we demonstrate a ROS-based tumor therapy by integrating LOx and the antiglycolytic drug Mito-LND into Fe₃O₄/g-C₃N₄ nanoparticles coated with CaCO₃ (denoted as FGLMC). The LOx can catalyze endogenous lactate to produce H₂O₂, which decomposes cascades into ·OH and ¹O₂ through Fenton reaction-induced CDT and photo-triggered PDT. Meanwhile, the released Mito-LND contributes to metabolic therapy by cutting off the source of lactate and increasing ROS generation in mitochondria for further improvement in CDT and PDT. The results showed that the FGLMC nanoplatform can multifacetedly elevate ROS generation and cause fatal damage to cancer cells, leading to effective cancer suppression. This multidirectional ROS regulation strategy has therapeutic potential for different types of tumors.

Self-assembled iRGD-R7-LAHP-M nanoparticle induced sufficient singlet oxygen and enhanced tumor penetration immunological therapy

The generation of singlet oxygen (¹O₂) using photodynamic therapy (PDT) is limited by the hypoxia of the tumor microenvironment and the depth of external light penetration because it depends on the precise cooperation between the photosensitizers, oxygen, and light. Herein, we report a self-sufficient ¹O₂ nanoreactor with enhanced penetration into deep tumors for cancer therapy. Linoleic acid hydroperoxide (LAHP) is coordinated with transition metal ions (Cu²⁺/Fe³⁺) to prepare linoleic acid hydroperoxide metal complex nanoparticles (LAHP-M NPs). iRGD combined with R7 decoration endows the nanoparticles with tumor targeting and penetration ability. We show that the polypeptide carries the nanoparticles into deep tumors, and thereafter the nanoparticles are disassembled into LAHP and catalytical metal ions to produce ¹O₂ based on the Russell mechanism under the stimulation of acidic pH. The elevated ROS induces necrotic cell death in vitro and in vivo, and further causes immunogenic cell death (ICD). This study demonstrates the effectiveness of exploiting biochemical reactions as a spatial-temporal strategy to overcome the current limitations of photodynamic therapy.

Vitamin C supramolecular hydrogel for enhanced cancer immunotherapy

Vitamin C (VitC) has shown great promise to promote cancer immunotherapy, however, its high hydrophilicity makes it quickly excreted, leading to limited therapeutic efficiency even with frequent high-dose administration. Herein, we provide a pioneering report about the employment of VitC amphiphile self-assembled nanofiber hydrogels for enhanced cancer immunotherapy. Specifically, driven by hydrogen bonding and hydrophobic interactions, the synthesized VitC amphiphile, consisting of a hydrophilic VitC headgroup and a hydrophobic alkyl chain, could self-assemble into an injectable nanofiber hydrogel with self-healing properties. The formed VitC hydrogel not only serves as a reservoir for VitC but also acts as an effective delivery platform for stimulator of interferon genes (STING) agonist-4 (SA). Interestingly, the VitC hydrogel itself exhibits antitumor effects by upregulating genes related to interferon (IFN) signaling, apoptotic signaling and viral recognition and defense. Moreover, the SA-encapsulated VitC hydrogel (SA@VitC hydrogel) synergistically activated the immune system to inhibit the progression of both local and abscopal tumors.

Molecular imaging nanoprobes for theranostic applications

As a non-invasive imaging monitoring method, molecular imaging can provide the location and expression level of disease signature biomolecules in vivo, leading to early diagnosis of relevant diseases, improved treatment strategies, and accurate assessment of treating efficacy. In recent years, a variety of nanosized imaging probes have been developed and intensively investigated in fundamental/translational research and clinical practice. Meanwhile, as an interdisciplinary discipline, this field combines many subjects of chemistry, medicine, biology, radiology, and material science, etc. The successful molecular imaging not only requires advanced imaging equipment, but also the synthesis of efficient imaging probes. However, limited summary has been reported for recent advances of nanoprobes. In this paper, we summarized the recent progress of three common and main types of nanosized molecular imaging probes, including ultrasound (US) imaging nanoprobes, magnetic resonance imaging (MRI) nanoprobes, and computed tomography (CT) imaging nanoprobes. The applications of molecular imaging nanoprobes were discussed in details. Finally, we provided an outlook on the development of next generation molecular imaging nanoprobes.

Localized Enzyme-Assisted Self-Assembly of low molecular weight hydrogelators. Mechanism, applications and perspectives

Nature uses systems of high complexity coordinated by the precise spatial and temporal control of associated processes, working from the molecular to the macroscopic scale. This living organization is mainly ensured by enzymatic actions. Herein, we review the concept of Localized Enzyme-Assisted Self-Assembly (LEASA). It is defined and presented as a straightforward and insightful strategy to achieve high levels of control in artificial systems. Indeed, the use of immobilized enzymes to drive self-assembly events leads not only to the local formation of supramolecular structures but also to tune their kinetics and their morphologies. The possibility to design tailored complex systems taking advantage of self-assembled networks through their inherent and emergent properties offers new perspectives for the design of novel, more adaptable materials. As a result, some applications have already been developed and are gathered in this review. Finally, challenges and perspectives of LEASA are introduced and discussed.

Self-Amplifying Assembly of Peptides in Macrophages for Enhanced Inflammatory Treatment

Enzyme-regulated in situ self-assembly of peptides represents one versatile strategy in the creation of theranostic agents, which, however, is limited by the strong dependence on enzyme overexpression. Herein, we reported the self-amplifying assembly of peptides precisely in macrophages associated with enzyme expression for improving the anti-inflammatory efficacy of conventional drugs. The self-amplifying assembling system was created via coassembling an enzyme-responsive peptide with its derivative functionalized with a protein ligand. Reduction of the peptides by the enzyme NAD(P)H quinone dehydrogenase 1 (NQO1) led to the formation of nanofibers with high affinity to the protein, thereby facilitating NQO1 expression. The improved NQO1 level conversely promoted the assembly of the peptides into nanofibers, thus establishing an amplifying relationship between the peptide assembly and the NQO1 expression in macrophages. Utilization of the amplifying assembling system as vehicles for drug dexamethasone allowed for its passive targeting delivery to acute injured lungs. Both in vitro and in vivo studies confirmed the capability of the self-amplifying assembling system to enhance the anti-inflammatory efficacy of dexamethasone via simultaneous alleviation of the reactive oxygen species side effect and downregulation of proinflammatory cytokines. Our findings demonstrate the manipulation of the assembly of peptides in living cells with a regular enzyme level via a self-amplification process, thus providing a unique strategy for the creation of supramolecular theranostic agents in living cells.