Fe3O4@TiO2-Laden Neutrophils Activate Innate Immunity via Photosensitive Reactive Oxygen Species Release

Recent advances in cell membrane camouflaged nanotherapeutics for the treatment of bacterial infection

Infectious diseases caused by bacterial infections are common in clinical practice. Cell membrane coating nanotechnology represents a pioneering approach for the delivery of therapeutic agents without being cleared by the immune system in the meantime. And the mechanism of infection treatment should be divided into two parts: suppression of pathogenic bacteria and suppression of excessive immune response. The membrane-coated nanoparticles exert anti-bacterial function by neutralizing exotoxins and endotoxins, and some other bacterial proteins. Inflammation, the second procedure of bacterial infection, can also be suppressed through targeting the inflamed site, neutralization of toxins, and the suppression of pro-inflammatory cytokines. And platelet membrane can affect the complement process to suppress inflammation. Membrane-coated nanoparticles treat bacterial infections through the combined action of membranes and nanoparticles, and diagnose by imaging, forming a theranostic system. Several strategies have been discovered to enhance the anti-bacterial/anti-inflammatory capability, such as synthesizing the material through electroporation, pretreating with the corresponding pathogen, membrane hybridization, or incorporating with genetic modification, lipid insertion, and click chemistry. Here we aim to provide a comprehensive overview of the current knowledge regarding the application of membrane-coated nanoparticles in preventing bacterial infections as well as addressing existing uncertainties and misconceptions.

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.

Photocatalytic Antimicrobials: Principles, Design Strategies, and Applications

Nowadays, the increasing emergence of antibiotic-resistant pathogenic microorganisms requires the search for alternative methods that do not cause drug resistance. Phototherapy strategies (PTs) based on the photoresponsive materials have become a new trend in the inactivation of pathogenic microorganisms due to their spatiotemporal controllability and negligible side effects. Among those phototherapy strategies, photocatalytic antimicrobial therapy (PCAT) has emerged as an effective and promising antimicrobial strategy in recent years. In the process of photocatalytic treatment, photocatalytic materials are excited by different wavelengths of lights to produce reactive oxygen species (ROS) or other toxic species for the killing of various pathogenic microbes, such as bacteria, viruses, fungi, parasites, and algae. Therefore, this review timely summarizes the latest progress in the PCAT field, with emphasis on the development of various photocatalytic antimicrobials (PCAMs), the underlying antimicrobial mechanisms, the design strategies, and the multiple practical antimicrobial applications in local infections therapy, personal protective equipment, water purification, antimicrobial coatings, wound dressings, food safety, antibacterial textiles, and air purification. Meanwhile, we also present the challenges and perspectives of widespread practical implementation of PCAT as antimicrobial therapeutics. We hope that as a result of this review, PCAT will flourish and become an effective weapon against pathogenic microorganisms and antibiotic resistance.

Nanotherapeutics with immunoregulatory functions for the treatment of bacterial infection

The advent of drug-resistant pathogens results in the occurrence of stubborn bacterial infections that cannot be treated with traditional antibiotics. Antibacterial immunotherapy by reviving or activating the body's immune system to eliminate pathogenic bacteria has confirmed promising therapeutic strategies in controlling bacterial infections. Subsequent studies found that antimicrobial immunotherapy has its own benefits and limitations, such as avoiding recurrence of infection and autoimmunity-induced side effects. Current studies indicate that the various antibacterial therapeutic strategies inducing immune regulation can achieve superior therapeutic efficacy compared with monotherapy alone. Therefore, summarizing the recent advances in nanomedicine with immunomodulatory functions for combating bacterial infections is necessary. Herein, we briefly introduce the crisis caused by drug-resistant bacteria and the opportunity for antibacterial immunotherapy. Then, immune-involved multimodal antibacterial therapy for the treatment of infectious diseases was systematically summarized. Finally, the prospects and challenges of immune-involved combinational therapy are discussed.

Applications and Future Prospects of Micro/Nanorobots Utilizing Diverse Biological Carriers

Targeted drug delivery using micro-nano robots (MNRs) is a rapidly advancing and promising field in biomedical research. MNRs enable precise delivery of drugs, addressing a wide range of healthcare needs. However, the application of MNRs in vivo is limited by power issues and specificity in different scenarios. Additionally, the controllability and biological safety of MNRs must be considered. To overcome these challenges, researchers have developed bio-hybrid micro-nano motors that offer improved accuracy, effectiveness, and safety for targeted therapies. These bio-hybrid micro-nano motors/robots (BMNRs) use a variety of biological carriers, blending the benefits of artificial materials with the unique features of different biological carriers to create tailored functions for specific needs. This review aims to give an overview of the current progress and application of MNRs with various biocarriers, while exploring the characteristics, advantages, and potential hurdles for future development of these bio-carrier MNRs.

Advanced strategies to evade the mononuclear phagocyte system clearance of nanomaterials

Nanomaterials are promising carriers to improve the bioavailability and therapeutic efficiency of drugs by providing preferential drug accumulation at their sites of action, but their delivery efficacy is severely limited by a series of biological barriers, especially the mononuclear phagocytic system (MPS)-the first and major barrier encountered by systemically administered nanomaterials. Herein, the current strategies for evading the MPS clearance of nanomaterials are summarized. First, engineering nanomaterials methods including surface modification, cell hitchhiking, and physiological environment modulation to reduce the MPS clearance are explored. Second, MPS disabling methods including MPS blockade, suppression of macrophage phagocytosis, and macrophages depletion are examined. Last, challenges and opportunities in this field are further discussed.

A Zinc- and Calcium-Rich Lysosomal Nanoreactor Rescues Monocyte/Macrophage Dysfunction under Sepsis

Sepsis is a dysregulation of the immune response to pathogens and has high morbidity and mortality worldwide. However, the unclear mapping and course of dysregulated immune cells currently hinders the development of advanced therapeutic strategies to treat sepsis. Here, evidence is provided using single-cell RNA sequencing from peripheral blood mononuclear cells in sepsis that pathogens attacking monocytes/macrophages disrupt their immune function. The results reveal an enormous decline in monocytes/macrophages in sepsis and chart the evolution of their impaired phagocytosis (Pha) capabilities. Inspired by these findings, nanoparticles, named "Alpha-MOFs," are developed that target dysfunctional monocytes/macrophages to actively (A) lift (L) Pha by the release of lysosome-sensitive ions from a mineralized metal-organic framework (MOF). Alpha-MOFs have good stability and biosafety in peripheral blood and efficiently targeted monocytes/macrophages. They also release calcium and zinc ions into monocyte/macrophage lysosomes to promote the Pha and degradation of bacteria. Taken together, these results suggest that Alpha-MOFs rescue monocytes/macrophages dysfunction and effectively improve their survival rate during sepsis.

Neutrophil membrane-coated nanoparticles for enhanced nanosecond pulsed electric field treatment of pancreatic cancer

OBJECTIVE

Pancreatic cancer is one of the leading causes of cancer-related deaths worldwide. Poor prognosis and low survival rates have driven the development of novel therapeutic strategies. Nanosecond pulsed electric field has emerged as a novel, minimal invasive and non-thermal treatment for solid tumors. It is of great significance to study the combination therapy of nsPEF and other treatment strategies for pancreatic cancer.

METHODS

We developed neutrophil membrane-wrapped liposomal nanoparticles loaded with gemcitabine (NE/Lip-GEM) and investigated their use as a complementary agent for nsPEF treatment.

RESULTS

Our results showed that neutrophil-mediated delivery of liposomal-gemcitabine (NE/Lip-GEM) efficiently inhibited the growth of pancreatic tumors in mice whose has been treated with incomplete nsPEF ablation.

CONCLUSIONS

The combination of nsPEF and NE/Lip-GEM may be a promising synergistic strategy for pancreatic cancer therapy.

New Insight into Assembled Fe3O4@PEI@Ag Structure as Acceptable Agent with Enzymatic and Photothermal Properties

Metal-based enzyme mimics are considered to be acceptable agents in terms of their biomedical and biological properties; among them, iron oxides (Fe₃O₄) are treated as basement in fabricating heterogeneous composites through variable valency integrations. In this work, we have established a facile approach for constructing Fe₃O₄@Ag composite through assembling Fe₃O₄ and Ag together via polyethyleneimine ethylenediamine (PEI) linkages. The obtained Fe₃O₄@PEI@Ag structure conveys several hundred nanometers (~150 nm). The absorption peak at 652 nm is utilized for confirming the peroxidase-like activity of Fe₃O₄@PEI@Ag structure by catalyzing 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of H₂O₂. The Michaelis–Menten parameters (K_m) of 1.192 mM and 0.302 mM show the higher catalytic activity and strong affinity toward H₂O₂ and TMB, respectively. The maximum velocity (V_max) value of 1.299 × 10⁻⁷ M∙s⁻¹ and 1.163 × 10⁻⁷ M∙s⁻¹ confirm the efficiency of Fe₃O₄@PEI@Ag structure. The biocompatibility illustrates almost 100% cell viability. Being treated as one simple colorimetric sensor, it shows relative selectivity and sensitivity toward the detection of glucose based on glucose oxidase. By using indocyanine green (ICG) molecule as an additional factor, a remarkable temperature elevation is observed in Fe₃O₄@PEI@Ag@ICG with increments of 21.6 °C, and the absorption peak is nearby 870 nm. This implies that the multifunctional Fe₃O₄@PEI@Ag structure could be an alternative substrate for formatting acceptable agents in biomedicine and biotechnology with enzymatic and photothermal properties.

Usage of Nanoparticles to Alter Neutrophils' Function for Therapy

Neutrophils, the most abundant white blood cells in the human body, are important immune cells responsible for the innate immune response. Neutrophils can migrate to inflammatory areas, such as tumor sites and infection sites, because of chemotaxis. Neutrophil-based nanomaterials, such as neutrophil-nanomaterial composites and neutrophil membrane-based nanomaterials, can help the drug or imaging agent gather in the inflammatory area with the help of chemotaxis. In addition, some nanomaterials can interfere with the function of neutrophils to treat tissue damage caused by excessive local accumulation of neutrophils. This review focuses on the interaction between nanomaterials and neutrophils as well as the applications of neutrophil-based nanomaterials and neutrophil-interfering nanomaterials.

Interaction between iron oxide nanoparticles (Fe3O4 NPs) and human neutrophils: Evidence that Fe3O4 NPs possess some pro-inflammatory activities

Iron oxide nanoparticles (Fe₃O₄ NPs) are important for different medical applications. However, potential toxicity has been reported and several parameters must still be studied to reach highest therapeutic efficacy with minimal undesired effects. Inflammation is one of the most reported undesired effects of NP exposure in a variety of inflammatory models and conflicting data exist regarding whether Fe₃O₄ NPs possess pro- or anti-inflammatory activities. The aim of this study was to determine the direct effect of Fe₃O₄ NPs on the biology of neutrophil, a key player cell in inflammation. Freshly isolated human neutrophils were incubated in vitro with Fe₃O₄ NPs, and several functions have been studied. Using transmission electronic microscopy, Fe₃O₄ NPs were found to be ingested by neutrophils. These NPs do not induce a respiratory burst by themselves, but they increase the ability of neutrophils to adhere onto human endothelial cells as well as enhance phagocytosis. An antibody array approach revealed that Fe₃O₄ NPs induce the production of some cytokines, including the chemokine IL-8 (CXCL8), which was confirmed by ELISA. Fe₃O₄NPs were found to delay spontaneous neutrophil apoptosis regardless of sex of the donor. Using a pharmacological approach, we demonstrate that Fe₃O₄ NPs delay apoptosis by a de novo protein synthesis-dependent mechanism and via different cell signalling pathways. The data indicate that Fe₃O₄ NPs can alter the biology of human neutrophils and that they possess some pro-inflammatory effects, particularly based on their capacity to delay apoptosis and to induce the production of pro-inflammatory cytokines. Therefore, Fe₃O₄ NPs can regulate inflammation by targeting human neutrophil functions.

Blood cell-based drug delivery systems: a biomimetic platform for antibacterial therapy

With the rapid increase in multidrug-resistance against antibiotics, higher doses of antibiotics or more effective antibiotics are needed to treat diseases, which ultimately leads to a decrease in the body's immunity and seriously threatens human health worldwide. The efficiency of antibiotics has been a large challenge for years. To overcome this problem, many carriers are utilized for anti-bacteria, attempting to optimize the delivery of such drugs and transport them safely and directly to the site of disease. Blood cell-based drug delivery systems present several advantages as compared to polymeric delivery system. These blood cells including red blood cells (RBCs), leukocytes, platelets. The blood cells and their membranes can both be used as drug carriers to deliver antibacterial drugs. In addition, blood cells can overcome many physiological/pathological obstacles faced by nanoparticles in vivo and effectively deliver drugs to the site of the disease. In this paper, we review studies on blood cell-based delivery systems used in antibacterial therapy, and analyze different roles in antibacterial therapy, which provide basis for further study in this field.

Harnessing immune response using reactive oxygen Species-Generating/Eliminating inorganic biomaterials for disease treatment

With the increasing understanding of various biological functions mediated by reactive oxygen species (ROS) in the immune system, a number of studies have been designed to develop ROS-generating/eliminating strategies to selectively modulate immunogenicity for disease treatment. These strategies potentially exploit ROS-modulating inorganic biomaterials to harness host immunity to maximize the therapeutic potency by eliciting a favorable immune response. Inorganic biomaterial-guided in vivo ROS scavenging can exhibit several effects to: i) reduce the secretion of pro-inflammatory factors, ii) induce the phenotypic transition of macrophages from inflammatory M1 to immunosuppressive M2 phase, iii) minimize the recruitment and infiltration of immune cells. and/or iv) suppress the activation of nuclear factor kappa-B (NF-κB) pathway. Inversely, ROS-generating inorganic biomaterials have been found to be capable of: i) inducing immunogenic cell death (ICD), ii) reprograming tumor-associated macrophages from M2 to M1 phenotypes, iii) activating inflammasomes to stimulate tumor immunogenicity, and/or iv) recruiting phagocytes for antimicrobial therapy. This review provides a systematic and up-to-date overview on the progress related to ROS-nanotechnology mediated immunomodulation. We highlight how the ROS-generating/eliminating inorganic biomaterials can converge with immunomodulation and ultimately elicit an effective immune response against inflammation, autoimmune diseases, and/or cancers. We expect that contents presented in this review will be beneficial for the future advancements of ROS-based nanotechnology and its potential applications in this evolving field.

Applications of Titanium Dioxide Nanostructure in Stomatology

Breakthroughs in the field of nanotechnology, especially in nanochemistry and nanofabrication technologies, have been attracting much attention, and various nanomaterials have recently been developed for biomedical applications. Among these nanomaterials, nanoscale titanium dioxide (nano-TiO₂) has been widely valued in stomatology due to the fact of its excellent biocompatibility, antibacterial activity, and photocatalytic activity as well as its potential use for applications such as dental implant surface modification, tissue engineering and regenerative medicine, drug delivery carrier, dental material additives, and oral tumor diagnosis and treatment. However, the biosafety of nano-TiO₂ is controversial and has become a key constraint in the development of nano-TiO₂ applications in stomatology. Therefore, in this review, we summarize recent research regarding the applications of nano-TiO₂ in stomatology, with an emphasis on its performance characteristics in different fields, and evaluations of the biological security of nano-TiO₂ applications. In addition, we discuss the challenges, prospects, and future research directions regarding applications of nano-TiO₂ in stomatology that are significant and worthy of further exploration.

Silver nanoclusters show advantages in macrophage tracing in vivo and modulation of anti-tumor immuno-microenvironment

Macrophage-based nanomedicine represents an emerging powerful strategy for cancer therapy. Unfortunately, some obstacles and challenges limit the translational applications of macrophage-mediated nanodrug delivery system. For instance, tracking and effective cell delivery for targeted tumor sites remain to be overcome, and controlling the states of macrophages is still rather difficult due to their plastic nature in response to external stimuli. To address these critical issues, here, we reported a novel type of silver nanoclusters (AgNCs) with excellent fluorescent intensity, especially long-lasting cell labeling stability after endocytosis by macrophages, indicating promising applications in tracking macrophage-based nanomedicine delivery. Our mechanistic investigations uncovered that these merits originate from the escape of AgNCs from lysosomal degradation within macrophages. In addition, the AgNCs would prime the M1-like polarization of macrophages (at least in part) through the toll-like receptor 4 signaling pathway. The engineered macrophages laden with AgNCs could be employed for lung metastasis breast cancer treatment, showing the effective targeting propensity to metastatic tumors, remarkable regulation of tumor immune microenvironment and inhibition of tumor growth. Collectively, AgNC-trained macrophages appear to be a promising strategy for tumor immune-microenvironment regulation, which might be generalized to a wider spectrum of cancer therapeutics.

Surface processing for iron-based degradable alloys: A preliminary study on the importance of acid pickling

The formation of a heterogeneous oxidized layer, also called scale, on metallic surfaces is widely recognized as a rapid manufacturing event for metals and their alloys. Partial or total removal of the scale represents a mandatory integrated step for the industrial fabrication processes of medical devices. For biodegradable metals, acid pickling has already been reported as a preliminary surface preparation given further processes, such as electropolishing. Unfortunately, biodegradable medical prototypes presented discrepancies concerning acid pickling studies based on samples with less complex geometry (e.g., non-uniform scale removal and rougher surface). Indeed, this translational knowledge lacks a detailed investigation on this process, deep characterization of treated surfaces properties, as well as a comprehensive discussion of the involved mechanisms. In this study, the effects of different acidic media (HCl, HNO3, H3PO4, CH3COOH, H2SO4 and HF), maintained at different temperatures (21 and 60 °C) for various exposition time (15-240 s), on the chemical composition and surface properties of a Fe-13Mn-1.2C biodegradable alloy were investigated. Changes in mass loss, morphology and wettability evidenced the combined effect of temperature and time for all conditions. Pickling in HCl and HF solutions favor mass loss (0.03-0.1 g/cm2) and effectively remove the initial scale.

Synergistic Antibacterial Effect of Zinc Oxide Nanoparticles and Polymorphonuclear Neutrophils

Zinc oxide nanoparticles (ZnONPs) are inorganic nano-biomaterials with excellent antimicrobial properties. However, their effects on the anti-infection ability of the innate immune system remains poorly understood. The aim of the present study was to explore the potential immunomodulatory effects of ZnONPs on the innate immune system, represented by polymorphonuclear leukocytes (PMNs), and determine whether they can act synergistically to resist pathogen infections. In vitro experiment showed that ZnONPs not only exhibit obvious antibacterial activity at biocompatible concentrations but also enhance the antibacterial property of PMNs. In vivo experiments demonstrated the antibacterial effect of ZnONPs, accompanied by more infiltration of subcutaneous immune cells. Further ex vivo and in vitro experiments revealed that ZnONPs enhanced the migration of PMNs, promoted their bacterial phagocytosis efficiency, proinflammatory cytokine (TNF-α, IL-1β, and IL-6) expression, and reactive oxygen species (ROS) production. In summary, this study revealed potential synergistic effects of ZnONPs on PMNs to resist pathogen infection and the underlying mechanisms. The findings suggest that attempts should be made to fabricate and apply biomaterials in order to maximize their synergy with the innate immune system, thus promoting the host’s resistance to pathogen invasion.

CD301b+ macrophages mediate angiogenesis of calcium phosphate bioceramics by CaN/NFATc1/VEGF axis

Calcium phosphate (CaP) bioceramics are important for tissue regeneration and immune response, yet how CaP bioceramics influence these biological processes remains unclear. Recently, the role of immune cells in biomaterial-mediated regeneration, especially macrophages, has been well concerned. CD301b⁺ macrophages were a new subset of macrophages we have discovered, which were required for bioceramics-mediated bone regeneration. Nevertheless, the impact of CD301b⁺ macrophages on angiogenesis, which is a vital prerequisite to bone formation is yet indistinct. Herein, we found that CD301b⁺ macrophages were closely correlated to angiogenesis of CaP bioceramics. Additionally, depletion of CD301b⁺ macrophages led to the failure of angiogenesis. We showed that store-operated Ca²⁺ entry and calcineurin signals regulated the VEGF expression of CD301b⁺ macrophages via the NFATc1/VEGF axis. Inhibition of calcineurin effectively impaired angiogenesis via decreasing the infiltration of CD301b⁺ macrophages. These findings provided a potential immunomodulatory strategy to optimize the integration of angiogenesis and bone tissue engineering scaffold materials.

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BCP bioceramics need the involvement of CD301b⁺ macrophages to promote angiogenesis.

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Surrounding BCP, CD301b⁺ macrophages are controlled by CaN and SOCE to express VEGF.

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BCP bioceramics direct CD301b⁺ macrophages' infiltration partly through calcineurin.

The Advances of Neutrophil-Derived Effective Drug Delivery Systems: A Key Review of Managing Tumors and Inflammation

The chimeric trait of recruitment by inflammatory signals endows neutrophils with the functionality of migrating to inflamed tissues, which can be utilized to tailor novel drug delivery systems. In this review, we introduce a mechanism of neutrophil-derived drug delivery systems recruited into inflamed sites and provide insight into tumors and inflammation therapy. In particular, the advantages of neutrophils—their endogenous-derived neutrophil membrane, exosomes as drug carriers for augmented targeting, prolonged circulation, and improved biostability—were concluded. Subsequently, the latest application in the treatment of tumors and inflammation was elaborated upon, followed by a discussion of the future prospects to neutrophil-derived delivery systems. This promising system will provide new therapeutic avenues for the treatment of inflammation and tumors.

Activation of GATA-binding protein 4 regulates monocyte chemoattractant protein-1 and chemotaxis in periodontal ligament cells

BACKGROUND AND OBJECTIVES

Periodontitis is a chronic inflammatory disease of periodontal supporting tissues. The persistent inflammatory reaction depends on the release of chemokines to continuously recruit inflammation cells. GATA-binding protein 4 (GATA4) exerts effects on senescence and inflammation, while its role in periodontitis is far from clear. The present study aims to address the effect of GATA4 on regulating chemokines and the chemotaxis in periodontitis.

MATERIAL AND METHODS

Periodontitis rat models were constructed to detect the expression of GATA4 and the chemokine monocyte chemoattractant protein-1 (MCP-1) by immunohistochemistry. Lipopolysaccharide (LPS)-stimulated human periodontal ligament (PDL) cells and GATA4-knockdown by siRNA transient transfection PDL cells were used to explore the correlation between GATA4 and chemokines. Transwell assay was performed to detect the role of GATA4 for the recruitment effect of chemokines on macrophages. Mitogen-activated protein kinase (MAPK) inhibitors were scheduled to intervene in LPS-stimulated PDL cells to examine the association between MAPK signaling pathways and GATA4. The expression of GATA4, chemokines, or MAPK signaling molecules was determined by quantitative real-time polymerase chain reaction, western blotting, or cell immunofluorescence.

RESULTS

The expression of GATA4 and MCP-1 was significantly increased in periodontitis rat models and in LPS-stimulated PDL cells. Knockdown GATA4 inhibited the expression of GATA4 and MCP-1 as well as suppressed the recruitment of macrophage in LPS-stimulated PDL cells. Inhibitors of p38 and ERK1/2 signaling pathways significantly downregulated the increased expression of GATA4 and MCP-1 induced by LPS in PDL cells.

CONCLUSIONS

GATA-binding protein 4 could act as an upstream regulator of MCP-1 and as a downstream regulator of p38 and ERK1/2 signaling pathways to initiate inflammation response and regulate chemotaxis during the progression of periodontitis.

Dual-targeted and MRI-guided photothermal therapy via iron-based nanoparticles-incorporated neutrophils

Nanoparticle-mediated photothermal therapy (PTT) has shown promising capability for tumor therapy through the high local temperature at the tumor site generated by a photothermal agent (PTA) under visible or near-infrared (NIR) irradiation. Improving the accumulation of PTA at the tumor site is crucial to achieving effective photothermal treatment. Here, we developed temperature-activatable engineered neutrophils (Ne) by combining indocyanine green (ICG)-loaded magnetic silica NIR-sensitive nanoparticles (NSNP), which provide the potential for dual-targeted photothermal therapy. The combined effect of neutrophil targeting and magnetic targeting increased the accumulation of PTA at the tumor site. According to magnetic resonance imaging (MRI), the retention of intravenous injected NSNP-incorporated neutrophils within the tumor site was markedly augmented as compared to free NSNP. Furthermore, when irradiated by NIR, NSNP could cause a high local temperature at the tumor site and the thermal stimulation of neutrophils. The heat can kill tumor cells directly, and also lead to the death of neutrophils, upon which active substances with tumor-killing efficacy will be released to kill residual tumor cells and thus reduce tumor recurrence. Thereby, our therapy achieved the elimination of malignancy in the mouse model of the pancreatic tumor without recurrence. Given that all materials used in this system have been approved for use in humans, the transition of this treatment method to clinical application is plausible.

Individualized plasticity autograft mimic with efficient bioactivity inducing osteogenesis

Mineralized tissue regeneration is an important and challenging part of the field of tissue engineering and regeneration. At present, autograft harvest procedures may cause secondary trauma to patients, while bone scaffold materials lack osteogenic activity, resulting in a limited application. Loaded with osteogenic induction growth factor can improve the osteoinductive performance of bone graft, but the explosive release of growth factor may also cause side effects. In this study, we innovatively used platelet-rich fibrin (PRF)-modified bone scaffolds (Bio-Oss^®) to replace autograft, and used cytokine (BMP-2) to enhance osteogenesis. Encouragingly, this mixture, which we named “Autograft Mimic (AGM)”, has multiple functions and advantages. (1) The fiber network provided by PRF binds the entire bone scaffold together, thereby shaping the bone grafts and maintaining the space of the defect area. (2) The sustained release of BMP-2 from bone graft promoted bone regeneration continuously. (3) AGM recruited bone marrow mesenchymal stem cells (BMSCs) and promote their proliferation, migration, and osteogenic differentiation. Thus, AGM developed in this study can improve osteogenesis, and provide new guidance for the development of clinical bone grafts.

Chemically Engineered Immune Cell-Derived Microrobots and Biomimetic Nanoparticles: Emerging Biodiagnostic and Therapeutic Tools

Over the past decades, considerable attention has been dedicated to the exploitation of diverse immune cells as therapeutic and/or diagnostic cell-based microrobots for hard-to-treat disorders. To date, a plethora of therapeutics based on alive immune cells, surface-engineered immune cells, immunocytes' cell membranes, leukocyte-derived extracellular vesicles or exosomes, and artificial immune cells have been investigated and a few have been introduced into the market. These systems take advantage of the unique characteristics and functions of immune cells, including their presence in circulating blood and various tissues, complex crosstalk properties, high affinity to different self and foreign markers, unique potential of their on-demand navigation and activity, production of a variety of chemokines/cytokines, as well as being cytotoxic in particular conditions. Here, the latest progress in the development of engineered therapeutics and diagnostics inspired by immune cells to ameliorate cancer, inflammatory conditions, autoimmune diseases, neurodegenerative disorders, cardiovascular complications, and infectious diseases is reviewed, and finally, the perspective for their clinical application is delineated.

Target Reprogramming Lysosomes of CD8+ T Cells by a Mineralized Metal-Organic Framework for Cancer Immunotherapy

T cell immunotherapy holds significant challenges in solid tumors, mainly due to the T cells' low activation and the decreased synthesis-release of therapeutic proteins, including perforin and granzyme B, which are present in lysosomes. In this study, a lysosome-targeting nanoparticle (LYS-NP) is developed by way of a mineralized metal-organic framework (MOF) coupled with a lysosome-targeting aptamer (CD63-aptamer) to enhance the antitumor effect of T cells. The MOF synthesized from Zn²⁺ and dimethylimidazole has good protein encapsulation and acid sensitivity, and is thus an ideal lysosomal delivery vector. Calcium carbonate (CaCO₃ ) is used to induce MOF mineralization, improve the composite material's stability in encapsulating therapeutic protein, and provide calcium ions with synergistic effects. Before mineralization, perforin and granzyme B-T cell-needed therapeutic proteins for tumors-are preloaded with the MOF. Moreover, T cells are pretreated with processed tumor-specific antigens to activate or produce memory before reprogramming the lysosomes, facilitating the T cell receptor (TCR) for release of the therapeutic proteins. Using T cells recombined by LYS-NPs, a significant enhancement of breast cancer control is confirmed.

Nano-peroxidase a Promising Anti-inflammatory and Antibacterial Agent Against Bacteria and Inflammation Related to Colorectal Cancer

BACKGROUND

Colorectal cancer (CRC) is one of the most common causes of cancer death in the world. Although genes are considered the most importantcauses that contribute to CRC, the intestinal microorganisms are an important player. Recently, various studies ensured the role of microbial infection and the ensuing inflammation in colon cancer initiation and progression. This present study tries to introduce a cheap nano-peroxidase (an antioxidant enzyme) produced from natural sources as efficient and safe antibacterial and anti-inflammatory agent against bacteria and inflammation related to colorectal cancer.

METHODS

Silica nanoparticles were prepared from rice straw. Peroxidase extracted from the dry onion scales was then immobilized on the prepared nanosilica (nano-peroxidase). The antibacterial activity of the prepared nano-peroxidase was tested against the four horsemen bacteria in CRC, Fusobacterium nucleatum, Escherichia coli, Bacteroides fragilis, and Salmonella enterica. The in vitro anti-inflammatory activity of the prepared nano-peroxidase also tests through performing inhibition of albumin denaturation test.

RESULTS

The prepared nano-peroxidase showed high antibacterial activity against the tested bacteria in presence of very low concentration of H2O2. Immobilization increased the peroxidase stability and protected it from hydrolysis enzymes produced by the bacteria. The prepared nano-peroxidase interestingly showed significant higher anti-inflammatory activity than that of the standard (Aspirin).

CONCLUSION

Nano-peroxidase can be considered a promising safe anti-inflammatory and antibacterial agent against bacteria and inflammation related to colorectal cancer.

A bifunctionalized NiCo2O4-Au composite: Intrinsic peroxidase and oxidase catalytic activities for killing bacteria and disinfecting wound

A NiCo₂O₄-Au composite was fabricated following the calcination-reduction method and testified to exhibit the intrinsic high peroxidase- and oxidase-like activities. The composite could activate a low level of H₂O₂ (100 μM) to kill E. coli and S. aureus. NiCo₂O₄-Au composite could be easily separated by an external magnet from the media and reused several times. NiCo₂O₄-Au composite could also effectively damage the existing biofilms and prevent the formation of new biofilms. The electron spin resonance tests showed that NiCo₂O₄-Au composite catalyzed H₂O₂ into reactive oxygen species (ROS), mainly including OH, O₂^-, and ¹O₂; while the oxidase-like activity of NiCo₂O₄-Au also stemmed from the ROS formation in the absence of H₂O₂. The radical trapping experiment confirmed that OH and ¹O₂ were the main radicals in the antibacterial process for NiCo₂O₄-Au in the presence of H₂O₂. A NiCo₂O₄-Au based Band-Aid was also designed, which exhibited high anti-infective and wound-healing properties. This study has demonstrated that NiCo₂O₄-Au composite can be a promising antibacterial agent in environmental and clinical applications.

Cell-Membrane-Display Nanotechnology

Advances in material science have set the stage for nanoparticle-based research with potent applications for the diagnosis, bioimaging, and precise treatment of diseases. Despite the wide range of biomaterials developed, the rational design of biomaterials with predictable bioactivity and safety remains a critical challenge. In recent years, the field of cell-membrane-based therapeutics has emerged as a promising platform for addressing unmet medical needs. The utilization of natural cell membranes endows biomaterials with a remarkable ability to serve as biointerfaces that interact with the host environment. To improve the function and efficacy of cell-membrane-based therapeutics, a series of novel strategies is developed as cell-membrane-display nanotechnology, which utilizes various methods to selectively display therapeutic molecules of cell membranes on nanoparticles. Although cell-membrane-display nanotechnology remains in the early phases, considerable work is currently being conducted in the field. This review discusses details of innovative strategies for displaying cell-membrane molecules, including the following: 1) displaying molecules of cell membranes on biomaterials, 2) pretreating cell membranes to induce increased expression of inherent molecules of cell membranes and enhance their function, and 3) inserting additional functional molecules on cell membranes. For each area, the theoretical basis, application scenarios, and potential development are highlighted.

Multi-Component Mesocrystalline Nanoparticles with Enhanced Photocatalytic Activity

Mesocrystals, consisting of small subunits, have gained research interests owing to their ability to simultaneously modify material-specific properties and interactions among subunits. However, despite these unique characteristics, most mesocrystals are composed of a single material, and there is a disjunction between academic discovery and practical application. In this study, the synthesis of multi-component mesocrystalline nanoparticles composed of Fe₃ O₄ , ZnFe₂ O₄ , and ZnO subunits using a polymerization induced heterogeneous nucleation method is reported. The structure has small ZnFe₂ O₄ and ZnO nanocrystals covering the Fe₃ O₄ crystallites. It exhibits not only magnetic and catalytic properties determined by the size of each subunit nanocrystal, but also enhances photocatalytic and colloidal properties that originates because of its crowded arrangement. The magnetically recoverable catalysts exhibit remarkable photodegradation of organic molecules under the irradiation of visible light for 1 h; thus, improving its applicability in purifying a large amount of wastewater during the daytime.

Light-Excited Antibiotics for Potentiating Bacterial Killing via Reactive Oxygen Species Generation

The irrational or excessive use of antibiotics causes the emergence of bacterial resistance, making antibiotics less effective or ineffective. As the number of resistant antibiotics increases, it is crucial to develop new strategies and innovative approaches to potentiate the efficacy of existing antibiotics. In this paper, we report that some existing antibiotics can produce reactive oxygen species (ROS) directly under light irradiation. Thus, a novel antibacterial photodynamic therapy (PDT) strategy is proposed by using existing antibiotics for which the activities are potentiated via light-activation. This antibiotic-based PDT strategy can achieve efficient bacteria killing with a low dosage of antibiotics, indicating that bacterial killing can be enhanced by the light-irradiated antibiotics. Moreover, the specific types of ROS produced by different antibiotics under light irradiation were studied for better elucidation of the antibacterial mechanism. The findings can extend the application of existing antibiotics and provide a promising strategy for treatment of bacterial infections and even cancers.