Advanced biomimetic nanoreactor for specifically killing tumor cells through multi-enzyme cascade

Sustained-release of SOD from multivesicular liposomes accelerated the colonic mucosal healing of colitis mice by inhibiting oxidative stress

Oxidative stress has long been known as a pathogenic factor of ulcerative colitis. Superoxide dismutase (SOD) has been demonstrated to mitigate gut mucosal injury via combating oxidative stress. Herein, we developed SOD-loaded multivesicular liposomes (S-MVLs) as sustained-release depot for ulcerative colitis treatment. S-MVLs were spherical honeycomb-like particles with average particle size of 27.3 ± 5.4 μm and encapsulating efficiency of 78.7 ± 2.6 %. Moreover, the two-phase release profiles of SOD from S-MVLs were exhibited, that was, the burst release phase within 4 h and the sustained-release phase within 96 h. After intraperitoneally injecting S-MVLs, in situ retention time of SOD at bowel cavity extended by 4-fold in comparison with SOD solution. In vitro cells experiment showed that S-MVLs had the protective effect on LPS-treated RAW 264.7 cells via scavenging ROS and inhibiting pro-inflammatory cytokines production. S-MVLs ameliorated the body weight loss, DAI score and the colon shortening of colitis mice. Meanwhile, the colonic morphology and the epithelial barrier of colitis mice were effectively recovered after S-MVLs treatment. The therapeutic mechanism might be associated with polymerizing M1 macrophages to M2 phenotypes and alleviating oxidative stress. Collectively, multivesicular liposomes might be a promising sustained-release depot of SOD for ulcerative colitis treatments.

Multi-Enzyme Cascade Nanoreactors for High-Throughput Immunoassay: Transitioning Concept in Lab to Application in Community

In this work, we reported a cholesterol oxidase (Chox)-loaded platinum (Pt) nanozyme with the collaborative cascade nanoreactor for the construction of nanozyme-enzyme-linked immunosorbent assay (N-ELSA) models to realize high-throughput rapid evaluation of cancer markers. Considering the high specific surface area and manipulable surface sites, ZIF-8 was used as a substrate for natural enzyme and nanozyme loading. The constructed ZIF-8-Pt nanozyme platform exhibited efficient enzyme-like catalytic efficiency with a standard corrected activity of 60.59 U mg-1, which was 12 times higher than that of the ZIF-8 precursor, and highly efficient photothermal conversion efficiency (∼35.49%). In N-ELISA testing, developed multienzyme photothermal probes were immobilized in microplates based on antigen-antibody-specific reactions. Cholesterol was reacted in a cascade to reactive oxygen radicals, which attacked 3,3',5,5'-tetramethylbenzidine, causing it to oxidize and color change, thus exhibiting highly enhanced efficient photothermal properties. Systematic temperature evaluations were performed by a hand-held microelectromechanical system thermal imager under the excitation of an 808 nm surface light source to determine the cancer antigen 15-3 (CA15-3) profiles in the samples. Encouragingly, the temperature signal from the microwells increased with increasing CA15-3, with a linear range of 2 mU mL-1 to 100 U mL-1, considering it to be the sensor with the widest working range for visualization and portability available. This work provides new horizons for the development of efficient multienzyme portable colorimetric-photothermal platforms to help advance the community-based process of early cancer detection.

Biomimetic ZIF-8 Nanoparticles: A Novel Approach for Biomimetic Drug Delivery Systems

Metal-organic frameworks (MOFs) are porous materials resulting from the coordination of metal clusters or ions with organic ligands, merging macromolecular and coordination chemistry features. Among these, zeolitic imidazolate framework-8 (ZIF-8) stands out as a widely utilized MOF known for its robust stability in aqueous environments owing to the robust interaction between its constituent zinc ions (Zn2+) and 2-methylimidazole (2-MIM). ZIF-8 readily decomposes under acidic conditions, serving as a promising candidate for pH-responsive drug delivery systems. Moreover, biomimetic materials typically possess good biocompatibility, reducing immune reactions. By mimicking natural structures or surface features within the body, they enhance the targeting of nanoparticles, prolong their circulation time, and increase their bioavailability in vivo. This review explores the latest advancements in biomimetic ZIF-8 nanoparticles for drug delivery, elucidating the primary obstacles and future prospects in utilizing ZIF-8 for drug delivery applications.

Identification and functional characterization of a superoxide dismutase (CuZnSOD) from Pinctada fucata martensii

Copper/zinc superoxide dismutase (Cu/Zn-SOD) can effectively eliminate reactive oxygen species (ROS)，avoid damage from O2 to the body, and maintain O2 balance. In this study, multi-step high-performance liquid chromatography (HPLC), combined with Mass Spectrometry (MS), was used to isolate and identify Cu/Zn-SOD from the serum of Pinctada fucata martensii (P. f. martensii) and was designated as PmECSOD. With a length of 1864 bp and an open reading frame (ORF) of 1422 bp, the cDNA encodes a 473 amino acid protein. The PmECSOD transcript was detected in multiple tissues by quantitative real-time PCR (qRT-PCR), with its highest expression level being in the gills. Additionally, the temporal expression of PmECSOD mRNA in the hemolymph was highest at 48 h after in vivo stimulation with Escherichia coli and Micrococcus luteus. The results from this study provide a valuable base for further exploration of molluscan innate immunity and immune response.

Targeted cancer treatment using folate-conjugated sponge-like ZIF-8 nanoparticles: a review

ZIF-8 (zeolitic imidazolate framework-8) is a potential drug delivery system because of its unique properties, which include a large surface area, a large pore capacity, a large loading capacity, and outstanding stability under physiological conditions. ZIF-8 nanoparticles may be readily functionalized with targeting ligands for the identification and absorption of particular cancer cells, enhancing the efficacy of chemotherapeutic medicines and reducing adverse effects. ZIF-8 is also pH-responsive, allowing medication release in the acidic milieu of cancer cells. Because of its tunable structure, it can be easily functionalized to design cancer-specific targeted medicines. The delivery of ZIF-8 to cancer cells can be facilitated by folic acid-conjugation. Hence, it can bind to overexpressed folate receptors on the surface of cancer cells, which holds the promise of reducing unwanted deliveries. As a result of its importance in cancer treatment, the folate-conjugated ZIF-8 was the major focus of this review.

Synthetic Biohybrids of Red Blood Cells and Cascaded-Enzymes@ Metal-Organic Frameworks for Hyperuricemia Treatment

Hyperuricemia, caused by an imbalance between the rates of production and excretion of uric acid (UA), may greatly increase the mortality rates in patients with cardiovascular and cerebrovascular diseases. Herein, for fast-acting and long-lasting hyperuricemia treatment, armored red blood cell (RBC) biohybrids, integrated RBCs with proximal, cascaded-enzymes of urate oxidase (UOX) and catalase (CAT) encapsulated within ZIF-8 framework-based nanoparticles, have been fabricated based on a super-assembly approach. Each component is crucial for hyperuricemia treatment: 1) RBCs significantly increase the circulation time of nanoparticles; 2) ZIF-8 nanoparticles-based superstructure greatly enhances RBCs resistance against external stressors while preserving native RBC properties (such as oxygen carrying capability); 3) the ZIF-8 scaffold protects the encapsulated enzymes from enzymatic degradation; 4) no physical barrier exists for urate diffusion, and thus allow fast degradation of UA in blood and neutralizes the toxic by-product H2 O2 . In vivo results demonstrate that the biohybrids can effectively normalize the UA level of an acute hyperuricemia mouse model within 2 h and possess a longer elimination half-life (49.7 ± 4.9 h). They anticipate that their simple and general method that combines functional nanomaterials with living cell carriers will be a starting point for the development of innovative drug delivery systems.

Current status and prospect of ZIF-based materials for breast cancer treatment

Breast cancer, one of the three most life-threatening cancers in modern times, must be explored for treatments with low side effects and practical efficacy. Metal organic framework materials (MOFs) is made by metal ions as the center for point and organic ligands as a bridge connecting a new type of porous nano-materials, among them, the zinc base zeolite imidazole skeleton material series (ZIFs) because of its excellent biocompatibility and pH slow controlled release ability, is widely used in the tumor microenvironment in basic research and achieved remarkable curative effect. Inspired by this, in this review, we focus on the recent research progress on the application of ZIFs in the treatment of breast cancer, mainly studying the structure of ZIFs such as ZIF-8, ZIF-90 and ZIF-67 and their application in novel therapies for breast cancer treatment, such as targeted drug delivery, photothermal therapy, immunotherapy and gene therapy.We will more fully demonstrate the potential of zif in breast cancer treatment, hoping to provide an avenue for exploring breast cancer treatment.

Tailored Beta-Lapachone Nanomedicines for Cancer-Specific Therapy

Nanotechnology shows the power to improve efficacy and reduce the adverse effects of anticancer agents. As a quinone-containing compound, beta-lapachone (LAP) is widely employed for targeted anticancer therapy under hypoxia. The principal mechanism of LAP-mediated cytotoxicity is believed due to the continuous generation of reactive oxygen species with the aid of NAD(P)H: quinone oxidoreductase 1 (NQO1). The cancer selectivity of LAP relies on the difference between NQO1 expression in tumors and that in healthy organs. Despite this, the clinical translation of LAP faces the problem of narrow therapeutic window that is challenging for dose regimen design. Herein, the multifaceted anticancer mechanism of LAP is briefly introduced, the advance of nanocarriers for LAP delivery is reviewed, and the combinational delivery approaches to enhance LAP potency in recent years are summarized. The mechanisms by which nanosystems boost LAP efficacy, including tumor targeting, cellular uptake enhancement, controlled cargo release, enhanced Fenton or Fenton-like reaction, and multidrug synergism, are also presented. The problems of LAP anticancer nanomedicines and the prospective solutions are discussed. The current review may help to unlock the potential of cancer-specific LAP therapy and speed up its clinical translation.

Breast cancer brain metastasis: from etiology to state-of-the-art modeling

Currently, breast carcinoma is the most common form of malignancy and the main cause of cancer mortality in women worldwide. The metastasis of cancer cells from the primary tumor site to other organs in the body, notably the lungs, bones, brain, and liver, is what causes breast cancer to ultimately be fatal. Brain metastases occur in as many as 30% of patients with advanced breast cancer, and the 1-year survival rate of these patients is around 20%. Many researchers have focused on brain metastasis, but due to its complexities, many aspects of this process are still relatively unclear. To develop and test novel therapies for this fatal condition, pre-clinical models are required that can mimic the biological processes involved in breast cancer brain metastasis (BCBM). The application of many breakthroughs in the area of tissue engineering has resulted in the development of scaffold or matrix-based culture methods that more accurately imitate the original extracellular matrix (ECM) of metastatic tumors. Furthermore, specific cell lines are now being used to create three-dimensional (3D) cultures that can be used to model metastasis. These 3D cultures satisfy the requirement for in vitro methodologies that allow for a more accurate investigation of the molecular pathways as well as a more in-depth examination of the effects of the medication being tested. In this review, we talk about the latest advances in modeling BCBM using cell lines, animals, and tissue engineering methods.

Effect of Cell Membrane-cloaked Nanoparticle Elasticity on Nano-Bio Interaction

Cell membrane-cloaked nanoparticles are exploited as a promising drug carrier to enhance circulation, accumulation, penetration into tumor sites and cellular internalization. However, the effect of physicochemical properties (e.g., size, surface charge, shape, and elasticity) of cell membrane-cloaked nanoparticles on nano-bio interaction is rarely studied. In the present study, keeping the other parameters constant, erythrocyte membrane (EM)-cloaked nanoparticles (nanoEMs) with different Young's moduli are fabricated by altering different kinds of nano-core (i.e., aqueous phase core, gelatin nanoparticles, and platinum nanoparticles). The designed nanoEMs are used to investigate the effect of nanoparticle elasticity on nano-bio interaction including cellular internalization, tumor penetration, biodistribution, blood circulation, and so on. The results demonstrate that the nanoEMs with intermediate elasticity (≈95 MPa) have a relatively higher increase in cellular internalization and inhibition of tumor cells migration than the soft (≈11 MPa) and stiff (≈173 MPa) ones. Furthermore, in vivo studies show that nanoEMs with intermediate elasticity preferentially accumulate and penetrate into tumor sites than the soft and stiff ones, while in circulation, softer nanoEMs show a longer blood circulation time. This work provides an insight for optimizing the design of biomimetic carriers and may further contribute to the selection of nanomaterials on biomedical application.

MOF-Immobilized Two-in-One Engineered Enzymes Enhancing Activity of Biocatalytic Cascade for Tumor Therapy

Biocatalytic systems based on enzyme cascade reactions have attracted growing interest in the field of biocatalytic medicine. However, it is a major challenge to reasonably construct enzyme cascade reactions with high stability, selectivity, and catalytic efficiency for the in vivo biocatalytic application. Herein, two-in-one engineered glucose oxidase (GOx-Fe⁰ ) is fabricated by a biomineralization strategy, through which a nanozyme (Fe⁰ NP) is anchored within the inner cavity of GOx. Then, GOx-Fe⁰ is immobilized in a pH-sensitive metal-organic framework (MOF) zeolitic imidazolate framework-8 (ZIF-8) to establish a stable and effective MOF-immobilized two-in-one engineered enzyme, GOx-Fe⁰ @ZIF-8. In vitro studies show that GOx-Fe⁰ @ZIF-8 exhibits excellent stability and high pH/glucose selectivity, and the shorter spacing between cascade enzymes can increase the cascade throughput and effectively improve the reaction efficiency of the enzyme cascade. In vivo experiments exhibit that GOx-Fe⁰ @ZIF-8 solves the instability and systemic toxicity of free enzymes, and achieves deep tumor penetration and significant chemodynamic therapeutic efficacy through a pH/glucose-selective enzyme cascade reaction in tumor site. Taken together, such an orchestrated enzyme engineering strategy can effectively improve enzyme stability, selectivity, and enzyme cascade reaction efficiency via chemical transformations, and also provide a promising strategy for the application of biocatalytic cascade reactions in vivo.

Application of Spectroscopic Methods for the Identification of Superoxide Dismutases in Cyanobacteria

Superoxide dismutases (SODs) belong to the group of metalloenzymes that remove superoxide anion radicals and they have been identified in three domains of life: Bacteria, Archaea and Eucarya. SODs in Synechocystis sp. PCC 6803, Gloeobacter violaceus CCALA 979, and Geitlerinema sp. ZHR1A were investigated. We hypothesized that iron (FeSOD) and/or manganese (MnSOD) dominate as active forms in these cyanobacteria. Activity staining and three different spectroscopic methods of SOD activity bands excised from the gels were used to identify a suitable metal in the separated samples. FeSODs or enzymes belonging to the Fe-MnSOD superfamily were detected. The spectroscopic analyses showed that only Fe is present in the SOD activity bands. We found FeSOD in Synechocystis sp. PCC 6803 while two forms in G. violaceus and Geitlerinema sp. ZHR1A: FeSOD1 and FeSOD2 were present. However, no active Cu/ZnSODs were identified in G. violaceus and Geitlerinema sp. ZHR1A. We have shown that selected spectroscopic techniques can be complementary to the commonly used method of staining for SOD activity in a gel. Furthermore, the occurrence of active SODs in the cyanobacteria studied is also discussed in the context of SOD evolution in oxyphotrophs.

An extracellular Cu/Zn superoxide dismutase from Neocaridina denticulata sinensis: cDNA cloning, mRNA expression and characterizations of recombinant protein

Neocaridina denticulata sinensis possesses characters of rapid growth, tenacious vitality, short growth cycle, transparent, and easy feeding. Therefore, it is gradually being developed into an animal model for basic research on decapod crustaceans. Herein, a Cu/Zn superoxide dismutase (Cu/Zn-SOD), named as Nd-ecCu/Zn-SOD, was identified and characterized from N. denticulata sinensis. The full-length cDNA sequence of Nd-ecCu/Zn-SOD is 829 bp containing a 684 bp open reading frame, which encodes a protein of 227 amino acid residues with a typical Sod_Cu domain. The quantitative real-time PCR analysis showed that Nd-ecCu/Zn-SOD mRNA was expressed in all the tested tissues. Under challenge with copper, the mRNA expression of Nd-ecCu/Zn-SOD reached the maximum at 6 h, and decreased until 24 h. After 24 h of exposure, its expression was up-regulated significantly at 36 h. After then its expression sharply decreased with a comeback at 48 h. The result indicated that Nd-ecCu/Zn-SOD might play an important role in the stress response of N. denticulata sinensis. The expression of Nd-ecCu/Zn-SOD in gills challenged with Vibrio parahaemolyticus changed in a time-dependent manner. Nd-ecCu/Zn-SOD was lowly expressed in early developmental stages by RNA-Seq technology, yet it showed that a cyclical rise and fall occurred between middle stages and late stages. In addition, Nd-ecCu/Zn-SOD was recombinantly expressed using E. coli and the recombinant protein was purified as a single band on SDS-PAGE. The recombinant Nd-ecCu/Zn-SOD (rNd-ecCu/Zn-SOD) existed enzymatic activity under a wide range of temperature and pH. The exposure of metal ions was found that Zn²⁺, Mg²⁺, Ca²⁺, Ba²⁺, and Cu²⁺ could inhibit the enzymatic activity of rNd-ecCu/Zn-SOD, and Mn²⁺ increased the enzymatic activity of rNd-ecCu/Zn-SOD. These results indicate that Nd-ecCu/Zn-SOD may play a pivotal role in resistant against oxidative damage and act as a biomarker under stressful environment.

Recent advances in erythrocyte membrane-camouflaged nanoparticles for the delivery of anti-cancer therapeutics

INTRODUCTION

Red blood cell (or erythrocyte) membrane-camouflaged nanoparticles (RBC-NPs) not only have a superior circulation life and do not induce accelerated blood clearance, but also possess special functions, which offers great potential in cancer therapy.

AREAS COVERED

This review focuses on the recent advances of RBC-NPs for delivering various agents to treat cancers in light of their vital role in improving drug delivery. Meanwhile, the construction and in vivo behavior of RBC-NPs are discussed to provide an in-depth understanding of the basis of RBC-NPs for improved cancer drug delivery.

EXPERT OPINION

Although RBC-NPs are quite prospective in delivering anti-cancer therapeutics, they are still in their infancy stage and many challenges need to be overcome for successful translation into the clinic. The preparation and modification of RBC membranes, the optimization of coating methods, the scale-up production and the quality control of RBC-NPs, and the drug loading and release should be carefully considered in the clinical translation of RBC-NPs for cancer therapy.

Artificial Nanoplatelets Depend on Size for Precisely Inducing Thrombosis in Tumor Vessels

Due to the heterogeneity of a tumor, the tumor vascular interruption-based therapy has become an ideal treatment strategy. Herein, artificial nanoplatelets are reported to induce selective thrombosis in tumor vessels, which can achieve rapid and large-scale necrosis of tumor cells. For one, the nanoplatelets are exploited to specially release thrombin into target regions without affecting the established coagulation factors system. For another, the thrombin elicits vascular infarction to provide tumor-ablation effects. More importantly, the size-dependent effect of nanoplatelets (with diameters of 200, 400, and 800 nm) in vivo on blocking the tumor vessels is evaluated. The results show that the nanoplatelets from nanometer to submicron have achieved different biodistribution and therapeutic effects through the vascular transport. Notably, 400 nm scale nanoplatelets can induce thrombosis in tumor vessels and achieve 83% of the tumor elimination rate, thus manifesting the effectiveness of anti-tumor strategy compared with the other two scales of nanoplatelets (200 and 800 nm). These findings highlight the need of concern about nanoparticle size, providing a promising strategy for the future design of advanced vascular targeting reagents and the clinical translation of tumor vascular interruption-based therapy.

Rational design of non-toxic GOx-based biocatalytic nanoreactor for multimodal synergistic therapy and tumor metastasis suppression

Rationale: Glucose oxidase (GOx)-based biocatalytic nanoreactors can cut off the energy supply of tumors for starvation therapy and deoxygenation-activated chemotherapy. However, these nanoreactors, including mesoporous silica, calcium phosphate, metal-organic framework, or polymer nanocarriers, cannot completely block the reaction of GOx with glucose in the blood, inducing systemic toxicity from hydrogen peroxide (H₂O₂) and anoxia. The low enzyme loading capacity can reduce systemic toxicity but limits its therapeutic effect. Here, we describe a real 'ON/OFF' intelligent nanoreactor with a core-shell structure (GOx + tirazapamine (TPZ))/ZIF-8@ZIF-8 modified with the red cell membrane (GTZ@Z-RBM) for cargo delivery.

Methods: GTZ@Z-RBM nanoparticles (NPs) were prepared by the co-precipitation and epitaxial growth process under mild conditions. The core-shell structure loaded with GOx and TPZ was characterized for hydrate particle size and surface charge. The GTZ@Z-RBM NPs morphology, drug, and GOx loading/releasing abilities, system toxicity, multimodal synergistic therapy, and tumor metastasis suppression were investigated. The in vitro and in vivo outcomes of GTZ@Z-RBM NPs were assessed in 4T1 breast cancer cells.

Results: GTZ@Z-RBM NPs could spatially isolate the enzyme from glucose in a physiological environment, reducing systemic toxicity. The fabricated nanoreactor with high enzyme loading capacity and good biocompatibility could deliver GOx and TPZ to the tumors, thereby exhausting glucose, generating H₂O₂, and aggravating hypoxic microenvironment for starvation therapy, DNA damage, and deoxygenation-activated chemotherapy. Significantly, the synergistic therapy effectively suppressed the breast cancer metastasis in mice and prolonged life without systemic toxicity. The in vitro and in vivo results provided evidence that our biomimetic nanoreactor had a powerful synergistic cascade effect in treating breast cancer.

Conclusion: GTZ@Z-RBM NPs can be used as an 'ON/OFF' intelligent nanoreactor to deliver GOx and TPZ for multimodal synergistic therapy and tumor metastasis suppression.

Multienzyme nanoassemblies: from rational design to biomedical applications

Multienzyme nanoassemblies (MENAs) that combine the functions of several enzymes into one entity have attracted widespread research interest due to their improved enzymatic performance and great potential for multiple applications. Considerable progress has been made to design and fabricate MENAs in recent years. This review begins with an introduction of the up-to-date strategies in designing MENAs, mainly including substrate channeling, compartmentalization and control of enzyme stoichiometry. The desirable properties that endow MENAs with important applications are also discussed in detail. Then, the recent advances in utilizing MENAs in the biomedical field are reviewed, with a particular focus on biosensing, tumor therapy, antioxidant and drug delivery. Finally, the challenges and perspectives for development of versatile MENAs are summarized.

Metal-Coordinated Supramolecular Self-Assemblies for Cancer Theranostics

Metal-coordinated supramolecular nanoassemblies have recently attracted extensive attention as materials for cancer theranostics. Owing to their unique physicochemical properties, metal-coordinated supramolecular self-assemblies can bridge the boundary between traditional inorganic and organic materials. By tailoring the structural components of the metal ions and binding ligands, numerous multifunctional theranostic nanomedicines can be constructed. Metal-coordinated supramolecular nanoassemblies can modulate the tumor microenvironment (TME), thus facilitating the development of TME-responsive nanomedicines. More importantly, TME-responsive organic-inorganic hybrid nanomaterials can be constructed in vivo by exploiting the metal-coordinated self-assembly of a variety of functional ligands, which is a promising strategy for enhancing the tumor accumulation of theranostic molecules. In this review, recent advancements in the design and fabrication of metal-coordinated supramolecular nanomedicines for cancer theranostics are highlighted. These supramolecular compounds are classified according to the order in which the coordinated metal ions appear in the periodic table. Furthermore, the prospects and challenges of metal-coordinated supramolecular self-assemblies for both technical advances and clinical translation are discussed. In particular, the superiority of TME-responsive nanomedicines for in vivo coordinated self-assembly is elaborated, with an emphasis on strategies that enhance the accumulation of functional components in tumors for an ideal theranostic outcome.

Sensing Hydration of Biomimetic Cell Membranes

Biological membranes play a vital role in cell functioning, providing structural integrity, controlling signal transduction, and controlling the transport of various chemical species. Owing to the complex nature of biomembranes, the self-assembly of lipids in aqueous media has been utilized to develop model systems mimicking the lipid bilayer structure, paving the way to elucidate the mechanisms underlying various biological processes, as well as to develop a number of biomedical and technical applications. The hydration properties of lipid bilayers are crucial for their activity in various cellular processes. Of particular interest is the local membrane dehydration, which occurs in membrane fusion events, including neurotransmission, fertilization, and viral entry. The lack of universal technique to evaluate the local hydration state of the membrane components hampers understanding of the molecular-level mechanisms of these processes. Here, we present a new approach to quantify the hydration state of lipid bilayers. It takes advantage of the change in the lateral diffusion of lipids that depends on the number of water molecules hydrating them. Using fluorescence recovery after photobleaching technique, we applied this approach to planar single and multicomponent supported lipid bilayers. The method enables the determination of the hydration level of a biomimetic membrane down to a few water molecules per lipid.

Artificial M2 macrophages for disease-modifying osteoarthritis therapeutics

Osteoarthritis (OA) is one of the most common joint diseases worldwide and the focus is shifting to disease prevention and the pharmaceutical and surgical treatment of early OA. However, at present few have proven ability to block or delay the progression of OA. Nevertheless, M2 macrophages present an anti-inflammatory function and promote cartilage repair, thereby alleviating OA in mice. However, it is a significant challenge to regulate the helpful secretion of M2 macrophages on demand toward disease-modifying osteoarthritis therapeutics. Here, artificial M2 macrophage (AM2M) with yolk-shell structure was proposed and fabricated to enhance the therapeutic efficacy of M2 macrophages in the treatment of OA. AM2M was composed of macrophage membrane as "shell" and inflammation-responsive nanogel as "yolk". The nanogel was prepared via physical interaction of gelatin and chondroitin sulfate (ChS) through ionic bond and hydrogen bond, achieving burst release to down-regulate inflammation during acute flares and sustainable release to repair cartilage during low inflammatory activity. Furthermore, AM2M exhibited the targeting and long-term residence in the inflamed area and blocked the immune stimulation of macrophages by ChS. Therefore, our fabrication provided a new insight that artificial M2 macrophages are expected to break a vicious and self-perpetuating cycle of OA.

Recent advances in cell membrane coated metal-organic frameworks (MOFs) for tumor therapy

In improving the tumor-targeting ability of metal-organic frameworks (MOFs) for tumor therapy and avoiding the clearance as well as capture by the immune system, there are still several challenges, which limit the development and bio-applications of MOFs. To overcome these challenges, various targeted modification strategies have been proposed. Amongst all the strategies, a promising cell membrane coating method has been explored and utilized for the syntheses of new cell membrane biomimetic MOFs (CMMs). Through such coating, various source cell membranes (e.g., red blood cell, immune cell, cancer cell, platelet, and fusion cell membranes) can be endowed with excellent properties such as long blood circulation, immune escape, and targeting ability. In the presented perspective, the synthetic method, characterization, and research progress in tumor therapy based on CMMs have been summarized. This is because, like many other technologies, the cell membrane coating technology also has several challenges to overcome. Hence, addressing and overcoming such challenges will promote and extend the bio-applications of MOFs which in the future may become a prospective carrier for cancer nano-medicine. Finally, the prospects and challenges of utilizing CMMs for tumor therapy have been discussed.

3D printed intelligent scaffold prevents recurrence and distal metastasis of breast cancer

Rationale: Tumors are commonly treated by resection, which usually leads to massive hemorrhage and tumor cell residues, thereby increasing the risk of local recurrence and distant metastasis.

Methods: Herein, an intelligent 3D-printed poly(lactic-co-glycolic acid), gelatin, and chitosan scaffold loaded with anti-cancer drugs was prepared that showed hemostatic function and good pH sensitivity.

Results: Following in situ implantation in wounds, the scaffolds absorbed hemorrhage and cell residues after surgery, and promoted wound healing. In an in vivo environment, the scaffold responded to the slightly acidic environment of the tumor to undergo sustained drug release to significantly inhibit the recurrence and growth of the tumor, and reduced drug toxicity, all without causing damage to healthy tissues and with good biocompatibility.

Conclusions: The multifunctional intelligent scaffold represents an excellent treatment modality for breast cancer following resection, and provides great potential for efficient cancer therapy.

In Situ Cell Membrane Fusion for Engineered Tumor Cells by Worm-like Nanocell Mimics

Cell-based therapy is a promising clinic strategy to address many unmet medical needs. However, engineering cells faces some inevitable challenges, such as limited sources of cells, cell epigenetic alterations, and short shelf life during in vitro culture. Here, the worm-like nanocell mimics are fabricated to engineer effectively the tumor cells in vivo through the synergistic combination of nongenetic membrane surface engineering and inside encapsulation using in situ cell membrane fusion. The specific targeting and deformability of nanocell mimics play a vital role in membrane fusion mechanisms. The engineered primary tumor cells improved the tumor penetration of therapeutic cargoes via extracellular vesicles, while the engineered circulating tumor cells (CTCs) can capture the homologous cells to form the CTC clusters in the bloodstream and eliminate the CTC clusters in the lung, thus achieving excellent antitumor and antimetastasis efficacy. Above all, we find an intriguing phenomenon, in situ cell membrane fusion by the worm-like nanocell mimics, and our finding of in situ cell membrane fusion inspired us to engineer tumor cells in vivo. The present study would be a particularly meaningful strategy to directly engineer cells in vivo for cell-based therapy.