Bacterial outer membrane vesicles as potential biological nanomaterials for antibacterial therapy

Bacterial extracellular vesicles in the initiation, progression and treatment of atherosclerosis

Atherosclerosis is the primary cause of cardiovascular and cerebrovascular diseases. However, current anti-atherosclerosis drugs have shown conflicting therapeutic outcomes, thereby spurring the search for novel and effective treatments. Recent research indicates the crucial involvement of oral and gastrointestinal microbiota in atherosclerosis. While gut microbiota metabolites, such as choline derivatives, have been extensively studied and reviewed, emerging evidence suggests that bacterial extracellular vesicles (BEVs), which are membrane-derived lipid bilayers secreted by bacteria, also play a significant role in this process. However, the role of BEVs in host-microbiota interactions remains insufficiently explored. This review aims to elucidate the complex communication mediated by BEVs along the gut-heart axis. In this review, we summarize current knowledge on BEVs, with a specific focus on how pathogen-derived BEVs contribute to the promotion of atherosclerosis, as well as how BEVs from gut symbionts and probiotics may mitigate its progression. We also explore the potential and challenges associated with engineered BEVs in the prevention and treatment of atherosclerosis. Finally, we discuss the benefits and challenges of using BEVs in atherosclerosis diagnosis and treatment, and propose future research directions to address these issues.

Engineered cell membrane-based nano therapies fight infectious diseases

Infectious diseases continue to present significant global public health challenges, with pathogens such as bacteria and viruses posing substantial threats to human health. Conventional therapeutic approaches face several limitations, including the rising prevalence of drug resistance, suboptimal targeting, and adverse side effects, which collectively complicate clinical management. Cell membrane vesicles (MVs), characterized by their natural biocompatibility and outstanding drug delivery capabilities, have emerged as a promising platform for addressing these challenges in the treatment of infectious diseases. To further augment the therapeutic potential of MVs, engineering modifications have been extensively employed to enhance their functionality and efficacy. This review provides a comprehensive overview of the production and modification techniques associated with MVs, emphasizing recent advancements in the development of engineered membrane vesicles (EMVs) as versatile nanoplatforms for combating infectious diseases. Additionally, the clinical prospects and existing challenges of EMVs are critically analyzed, and recommendations are proposed to guide future research and facilitate their clinical translation into practical applications in combating infectious disease.

Polylysine Derivatives with a Potent Antibacterial Ability for Effectively Treating Methicillin-Resistant Staphylococcus aureus-Induced Endophthalmitis

Bacterial endophthalmitis (BE) is a severe ocular infection that can lead to irreversible blinding ocular disease. When diagnosed with BE, the main treatment approach is empirically administering intravitreal antibiotic injections. However, the excessive use of antibiotics leads to increased drug resistance in pathogens, and the retinal dose-limiting toxicities greatly limit its application in clinic. In this work, we present a series of polylysine derivatives (PLL-n) for the treatment of bacterial endophthalmitis. By precisely adjusting the balance of hydrophilic/hydrophobic, the optimal polymer, PLL-2, demonstrates high efficacy against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), and various clinically isolated drug-resistant bacteria. The antibacterial mechanism showed that PLL-2 could effectively destroy the bacterial membrane and lead to bacterial death. Due to its unique antibacterial mechanism, PLL-2 exhibits rapid bactericidal kinetics and does not induce bacterial resistance up to 16 generations. More importantly, PLL-2 showed a significant therapeutic effect on a methicillin-resistant S. aureus-induced rat endophthalmitis model, which presents a promising therapeutic approach for managing endophthalmitis.

Enhanced Photothermal Antimicrobial Effect of MXene-Doped PVA Electrospun Membranes via "Bedquilt-like" Synergistically Heat Modulation and Biological Effects of Bacteria-Derived OMVs for Infected Wound Treatment

Current treatments for skin infections employing single-agent antimicrobials have demonstrated pronounced limitations. Here, we have engineered an efficient antibacterial composite consisting of MXene and poly(vinyl alcohol) electrospun fibrous membranes, which are further functionalized with outer membrane vesicles (OMVs) using a tannic acid (TA) bridge. Upon near-infrared irradiation, OMVs augment the photothermal properties of MXene due to their "bedquilt effect". Meanwhile, the temperature rise facilitates active antibacterial substance release by increasing the permeability of the OMVs. The synergistically enhanced antimicrobial ability of the OMVs and photothermal materials achieves a potentiated antibacterial effect, resulting in a near 100% antibacterial efficacy in vitro and in vivo. This multifunctional, antibiotic-free dressing membrane, which integrates photothermal and biological antibacterial properties, presents a promising therapeutic strategy for the management of skin wound infections.

Beta-Lactam Antibiotics Promote Extracellular Vesicle Production of Staphylococcus aureus Through ROS-Mediated Lipid Metabolic Reprogramming

Bacterial extracellular vesicles (EVs) are natural reservoirs of biological active substances. They exhibit promising application in developing bioproducts such as vaccine, drug-delivery system and anticancer agent. However, the low yield of naturally secreted EVs during bacterial growth is a bottleneck factor that restricts EV applications. In this study, we showed that sub-minimum inhibitory concentration (MIC) of β-lactams boosted EV production in various Staphylococcus aureus strains. The expression of penicillin-binding protein (PBP) genes increased after β-lactam treatment, and the inactivation of alternative PBPs promoted EV secretion of S. aureus. We also demonstrated that sub-MIC β-lactams promoted EV production via a reactive oxygen species (ROS)-dependent pathway. Deletion of redundant pbp genes enhanced oxacillin (OXA)-stimulated ROS levels. Transcriptomic and lipidomic analyses revealed that OXA-induced ROS triggered lipid metabolic reprogramming in S. aureus. Particularly, ROS promoted lipid peroxidation (LPO) and increased the biosynthesis of phosphatidic acid (PA) and lipoteichoic acid (LTA) that contributed to EV generation. Furthermore, OXA treatment altered the diversity of EV-loaded proteins. OXA-treated ∆ agr /OXAEVs induced stronger Dengue EDIII-specific antibodies in BALB/c mice than did ∆ agrEVs. Overall, this study provided mechanic insights into β-lactam-promoted EV production in S. aureus, and highlighted the potential strategies to prepare EVs for various applications.

Highly antibacterial and biocompatible polylysine-modified silk fibroin for potential food preservation and biomedical applications

Bacterial infection remains a thorny problem in food, medicine, and other fields. Due to the emergence of antibiotic-resistant bacteria, it is critical to develop an effective strategy to yield novel antibacterial agents. Herein, a new type of non-antibiotic antimicrobial material was successfully synthesized by grafting ε-polylysine (EPL) onto silk fibroin (SF). The resulting ε-polylysine-modified silk fibroin (SF-EPL) possessed the possibility to be processed into different formats. As the EPL content increased, SF-EPL exhibited higher positive charge levels, similar to those of EPL. Notably, the incorporation of 10 % EPL endowed superior antibacterial effects against E. coli and S. aureus (>90 %), while maintaining excellent biocompatibility. Furthermore, SF-10%EPL effectively extended the shelf life of cherry tomatoes, significantly delaying weight loss and the decline in titratable acidity content. The obtained SF-EPL may represent a promising substitute for food preservation and biomedical applications.

Engineered bacterial outer membrane vesicles co-delivering Angio-3 and doxorubicin to enhance tumor therapy

Bacterial outer membrane vesicles (OMVs) have emerged as versatile nanomaterial-based drug delivery systems that can stimulate systemic immune responses and facilitate precise co-delivery of multiple therapeutic agents. This study introduces a bioengineering approach that enables the co-delivery of the angiogenesis inhibitor Angio-3 and the chemotherapeutic agent doxorubicin (DOX) within OMVs, creating a potent antitumor therapeutic platform. Angio-3 displayed on the surface of OMVs inhibited angiogenesis and decreased vascular permeability, which in turn impeded the supply of nutrients necessary for tumor growth. Moreover, intrinsic properties of OMVs triggered a systemic immune response. Both in vitro and in vivo studies, including a CT26 tumor-bearing mouse model, have demonstrated that the OMV@A&D-based therapeutic regimen, which integrates antiangiogenesis, chemotherapy, and immune activation, significantly suppresses tumor proliferation. This study highlights the potential of bioengineered OMVs in revolutionizing cancer therapy by offering a multifaceted and synergistic platform that enhances therapeutic outcomes.

Albumin as a functional carrier enhances solubilization, photodynamic and photothermal antibacterial therapy of curcumin

Bacterial infections are a significant threat to human health. Photodynamic therapy (PDT) and photothermal therapy (PTT) offer promising alternatives to antibiotic therapy. Curcumin (CUR) has shown great potentials in PDT, but its PTT was never reported. Also, its delivery and efficacy is highly limited by the poor water solubility. Herein, we report the antibacterial PTT of CUR for the first time. Furthermore, we successfully solubilized CUR, facilitated its delivery into bacterial cells, and enhanced its antibacterial PDT/PTT via using bovine serum albumin (BSA) as a carrier. The water solubility of CUR was enhanced from 10 to 298 μg/mL by forming CUR-BSA complex (containing 4 mg/mL BSA) which also enhanced the delivery of CUR into E. coli cells by >10 folds. Upon 450 nm irradiation, CUR-BSA (80 μg/mL) caused 94 % viability loss of E. coli, higher than 70 % loss caused by CUR, and more intracellular ROS was generated in CUR-BSA group. Interestingly, the antibacterial activity of CUR-BSA was reduced when the hyperthermia was depleted, suggesting its synergistic PDT/PTT effect. Considering the ready availability and great biocompatibility of albumin, our findings indicate that CUR-albumin complex may have great potentials in clinical use for antibacterial phototherapy.

New Advances in Periodontal Functional Materials Based on Antibacterial, Anti-Inflammatory, and Tissue Regeneration Strategies

With the global population aging, awareness of oral health is rising. Periodontitis, a widespread bacterial infectious disease, is gaining attention. Current novel biomaterials address key clinical issues like bacterial infection, gum inflammation, tooth loosening, and loss, focusing on antibacterial, anti-inflammatory, and tissue regeneration properties. However, strategies that integrate the advantages of these biomaterials to achieve synergistic therapeutic effects by clearing oral biofilms, inhibiting inflammation activation, and restoring periodontal soft and hard tissue functions remain very limited. Recent studies highlight the link between periodontitis and systemic diseases, underscoring the complexity of the periodontal disease. There is an urgent need to find comprehensive treatment plans that address clinical requirements. Whether by integrating new biomaterials to enhance existing periodontal treatments or by developing novel approaches to replace traditional therapies, these efforts will drive advancements in periodontitis treatment. Therefore, this review compares novel biomaterials with traditional treatments. It highlights the design concepts and mechanisms of these functional materials, focusing on their antibacterial, anti-inflammatory, and tissue regeneration properties, and discusses the importance of developing comprehensive treatment strategies. This review aims to provide guidance for emerging periodontitis research and to promote the development of precise and efficient treatment strategies.

Role of exosomes in dental and craniofacial regeneration - A review

BACKGROUND

The treatment of congenital deformities, traumatic injuries, infectious diseases, and tumors in the craniomaxillofacial (CMF) region is complex due to the intricate nature of the tissues involved. Conventional treatments such as bone grafts and cell transplantation face limitations, including the need for multiple surgeries, complications, and safety concerns.

OBJECTIVE

This paper aims to provide a comprehensive analysis of the role of exosomes (EXOs) in CMF and dental tissue regeneration and to explore their potential applications in regenerative dental medicine.

METHODS

An extensive review of advancements in tissue engineering, materials sciences, and nanotechnology was conducted to evaluate the development of delivery systems for EXOs-based therapies. The analysis included how EXOs, as nanovesicles released by cells, can be modified to target specific cells or loaded with functional molecules for drug or gene delivery.

RESULTS

EXOs have emerged as a promising alternative to cell transplant therapy, offering a safer method for cell communication and epigenetic control. EXOs transport important proteins and genetic materials, facilitating intercellular communication and delivering therapeutics effectively. The potential of EXOs in personalized medicine, particularly in diagnosing, customizing treatment, and predicting patient responses, is highlighted.

CONCLUSION

EXO-mediated therapy holds significant potential for advancing tissue regeneration, offering targeted, personalized treatment options with reduced side effects. However, challenges in purification, production, and standardized protocols need to be addressed before its clinical application can be fully realized.

NIR-triggered and glucose-powered hollow mesoporous Mo-based single-atom nanozymes for cascade chemodynamic diabetic infection therapy

Diabetic infections/wounds remain to be a threatening challenge as it seriously leads to lower limb amputation with endless pains and subsequent high economic/psychosocial costs. The exceptional peroxidase-like activity of single-atom nanozymes (SAzymes) holds great promise for chemodynamic therapy (CDT) of diabetic infection, but is extremely restricted by the near-neutral pH and insufficient H2O2 levels in physiological conditions. Herein, we innovated a hollow mesoporous molybdenum single-atom nanozyme (HMMo-zyme) featured with catalytic activity, photothermal performance and drug delivery properties for more effective antibacterial therapeutic in diabetic conditions. The glucose oxidase (GOx) was encapsulated into HMMo-zyme with phase-change material (PCM) to form HMMo/GOx@P system, which could be controllably disassembled by near-infrared ray (NIR) to trigger cascade CDT toward bacterial infections. The results revealed that the release of GOx accelerated by NIR could facilitate the continuous conversion of glucose (Glu) into gluconic acid, accompanied by a sharply decrease in pH to establish a low-pH environment that notably enhanced the catalytic activity of HMMo-zyme, which subsequently drives the conversion of generated H2O2 into toxic hydroxyl radicals (·OH) for amplified anti-bacterial treatment. As a proof of the concept, this NIR-assisted HMMo/GOx@P strategy could efficiently inhibit/kill bacteria and suppress tissue inflammations, thereby accelerating the wound healing processes both in in vitro and in vivo diabetic infection models. This study provides a novel strategy that may serve as a promising alternative for antibiotic therapeutics against diabetic infection, thus holding promise for more effective diabetic infection treatment manipulating Mo-based SAzymes.

Hybrid Outer Membrane Vesicles with Genetically Engineering for Treatment of Implant-Associated Infections and Relapse Prevention Through Host Immunomodulation

Implant-associated infections (IAIs) are refractory to elimination, and the local immunosuppressive microenvironment (IME) exacerbates therapeutic difficulties, ultimately causing persistence and relapse. Therefore, exploring immunostrengthening treatments holds great promise for reversing IME and thoroughly eradicating chronic or repetitive infections. Bacterial outer membrane vesicles (OMVs) have emerged as potential immunostimulatory candidates; however, they lack active targeting capabilities and cause non-specific inflammatory side effects. In this study, bone marrow-derived mesenchymal stem cells (BMSCs) are genetically engineered to overexpress CXCR4 and isolated cell membranes (mBMSCCXCR4) for hybridization with OMVs derived from Escherichia coli (E. coli) to produce nanovesicles (mBMSCCXCR4@OMV). The resulting mBMSCCXCR4@OMV nanovesicles demonstrate excellent bone marrow targeting capability and are effectively taken up by bone marrow-derived macrophages, triggering the efficient transition to pro-inflammatory M1 status through TLR/NF-κB pathway. This alteration promotes innate bactericidal capacity and antigen presentation. Subsequent activation of T and B cells and inhibition of myeloid-derived suppressor cells (MDSCs) facilitated in vivo adaptive immunity in mouse models. Additionally, mBMSCCXCR4@OMV boosted memory B cell and bacteria-specific antibody responses. Together, these data highlight the potential of mBMSCCXCR4@OMV to eradicate complicated IAIs and provide whole-stage protection against postsurgical relapse, thus marking a significant immunotherapeutic advancement in the post-antibiotic era.

Bacterial outer membrane vesicles in tumor prevention and treatment: advancements in research and application

As one of the major challenges to global health, the innovation of prevention and treatment methods for tumors has consistently been a focal point in medical research. In recent years, bacterial membrane vesicles (MVs), particularly outer membrane vesicles (OMVs) secreted by Gram-negative bacteria, have garnered significant attention due to their unique biological characteristics and potential anti-tumor effects. OMVs are bilayer lipid nanocapsules that are actively released by bacteria during their growth, typically ranging in diameter from 20 to 300 nm. They are rich in various biomolecules, including lipids, proteins, nucleic acids, and other small molecules. These components not only reflect the outer membrane structure of bacteria but also contain numerous pathogen-associated molecular patterns (PAMPs) related to bacterial pathogenicity and immunogenicity. Consequently, OMVs play an important role in bacterial resistance, antimicrobial activity, gene transfer, signal transduction, and immune regulation. Research and application of OMVs in anti-tumor therapy have made significant progress. This paper reviews the classification, characteristics, preparation, safety evaluation, biological functions, and specific research advancements of OMVs as antitumor drugs, immunomodulators, and carriers. Additionally, common methods for the preparation and modification of OMVs, including preliminary extraction, purification, characterization, and drug loading, are discussed. This paper also summarizes the challenges faced by OMVs in anti-tumor research and outlines future development directions, aiming to provide a reference for the further application of OMVs in tumor treatment.

Nanomaterial-enabled anti-biofilm strategies: new opportunities for treatment of bacterial infections

Biofilms play a pivotal role in bacterial pathogenicity and antibiotic resistance, representing a major challenge in the treatment of bacterial infections. The limited diffusion and inactivation efficacy of antibiotics within biofilms hinder their clearance, and while increasing dosage may enhance effectiveness, it also promotes antibiotic resistance. Nano-delivery systems that target antimicrobial agents directly to biofilms offer a promising strategy to overcome this challenge. This review summarizes the resistance mechanisms and therapeutic challenges associated with biofilms, with a focus on recent advances in nano-delivery systems such as liposomes, nanoemulsions, cell membrane vesicles (CMVs), polymers, dendrimers, nanogels, inorganic nanoparticles, and metal-organic frameworks (MOFs). Furthermore, the review explores the potential applications and challenges of nano-delivery systems in biofilm treatment and provides recommendations to guide future research and development in this field.

The role and mechanisms of Helicobacter pylori outer membrane vesicles in the pathogenesis of extra-gastrointestinal diseases

Helicobacter pylori (H. pylori) infection have been closely associated with several extra-gastrointestinal disorders. Outer membrane vesicles (OMVs), as lipid-membrane-bounded nanoparticles, are usually shed from Gram-negative both in vitro and in vivo. H. pylori is also capable of producing OMVs, which can enter the systemic circulation and be delivered to various cells, tissues or organs, eliciting a range of inflammatory and immune modulation responses. In this current review, we summarize the biogenesis and functions of H. pylori OMVs, describe the contribution of H. pylori OMVs to the generation and progression of extra-gastrointestinal diseases, such as neuronal damage, Alzheimer disease, hepatic fibrosis and atherosclerosis. We also explored the effect of H. pylori OMVs in inflammatory and immune modulation of diverse immune cells, including macrophages, mononuclear cells and dendritic cells. By elucidating the molecular mechanism of H. pylori OMVs-mediated extra-gastrointestinal diseases and immunomodulatory effect, it may promote the development of efficient treatments and vaccinations against H. pylori.

The Therapeutic Potential of Exosome Therapy in Sepsis Management: Addressing Complications and Improving Outcomes"

Infection occurs when pathogens penetrate tissues, reproduce, and trigger a host response to both the infectious agents and their toxins. A diverse array of pathogens, including viruses and bacteria, can cause infections. The host's immune system employs several mechanisms to combat these infections, typically involving an innate inflammatory response. Inflammation is a complex biological reaction that can affect various parts of the body and is a key component of the response to harmful stimuli. Sepsis arises when the body's response to infection leads to widespread damage to tissues and organs, potentially resulting in severe outcomes or death. The initial phase of sepsis involves immune system suppression. Early identification and targeted management are crucial for improving sepsis outcomes. Common treatment approaches include antibiotics, intravenous fluids, blood cultures, and monitoring urine output. This study explores the potential of exosome therapy in enhancing the management and alleviation of sepsis symptoms.

Modification of Liposomal Properties by an Engineered Gemini Surfactant

Lipid membranes form the primary structure of cell membranes and serve as configurable interfaces across numerous applications including biosensing technologies, antifungal treatments, and therapeutic platforms. Therefore, the modification of lipid membranes by additives has important consequences in both biological processes and practical applications. In this study, we investigated a nicotinic-acid-based gemini surfactant (NAGS) as a chemically tunable molecular additive for modulating the structure and phase behavior of liposomal membranes. We specifically focused on NAGS with hydrocarbon chains that mirror those of lipid molecules. By introducing NAGS to phosphatidylcholine membranes with lipids of identical and varied chain lengths or degrees of unsaturation, we demonstrated the effects of headgroup interactions and chain mismatch between NAGS and membrane lipids. Using small-angle X-ray scattering, we showed that regardless of chain compatibility or mismatch, NAGS reduced the thickness and packing density of fluid lipid membranes. Further observations by fluorescence microscopy revealed the emergence of ordered-disordered domains upon cooling to room temperature. The observed phases were quite distinct from those of lipid membranes with analogous chain compositions, emphasizing the importance of NAGS headgroup chemistry in mediating domain formation and stabilization. These findings open new possibilities for exploiting NAGS in tuning the structure and organization of liposomal membranes with potential applications in drug delivery and biomedical imaging.

Bacterial and bacterial derivatives-based drug delivery systems: a novel approach for treating central nervous system disorders

INTRODUCTION

Bacteria and their derivatives show great potential as drug delivery systems due to their unique chemotaxis, biocompatibility, and targeting abilities. In CNS disease treatment, bacterial carriers can cross the blood-brain barrier (BBB) and deliver drugs precisely, overcoming limitations of traditional methods. Advances in genetic engineering, synthetic biology, and nanotechnology have transformed these systems into multifunctional platforms for personalized CNS treatment.

AREAS COVERED

This review examines the latest research on bacterial carriers for treating ischemic brain injury, neurodegenerative diseases, and gliomas. Bacteria efficiently cross the blood-brain barrier via active targeting, endocytosis, paracellular transport, and the nose-to-brain route for precise drug delivery. Various bacterial drug delivery systems, such as OMVs and bacterial ghosts, are explored for their design and application. Databases were searched in Google Scholar for the period up to December 2024.

EXPERT OPINION

Future developments in bacterial drug delivery will rely on AI-driven design and high-throughput engineering, enhancing treatment precision. Personalized medicine will further optimize bacterial carriers for individual patients, but challenges such as biosafety, immune rejection, and scalability must be addressed. As multimodal diagnostic and therapeutic strategies advance, bacterial carriers are expected to play a central role in CNS disease treatment, offering novel precision medicine solutions.

Review on bacterial outer membrane vesicles: structure, vesicle formation, separation and biotechnological applications

Outer membrane vesicles (OMVs), shed by Gram-negative bacteria, are spherical nanostructures that play a pivotal role in bacterial communication and host-pathogen interactions. Comprising an outer membrane envelope and encapsulating a variety of bioactive molecules from their progenitor bacteria, OMVs facilitate material and informational exchange. This review delves into the recent advancements in OMV research, providing a comprehensive overview of their structure, biogenesis, and mechanisms of vesicle formation. It also explores their role in pathogenicity and the techniques for their enrichment and isolation. Furthermore, the review highlights the burgeoning applications of OMVs in the field of biomedicine, emphasizing their potential as diagnostic tools, vaccine candidates, and drug delivery vectors.

Consistency in bacterial extracellular vesicle production: key to their application in human health

Bacterial extracellular vesicles (BEVs) are naturally occurring functional structures that play critical roles in bacterial life processes. These vesicles, commonly known as outer membrane vesicles (OMVs), were first found to be released by Gram-negative bacteria; however, it has since been confirmed that Gram-positive bacteria also secrete BEVs. As research advances, BEVs are increasingly utilized in diverse applications, including vaccine development and drug delivery. Nevertheless, the effective employment of BEVs in these contexts requires the acquisition of vesicles with consistent properties and functions through appropriate culture, isolation, and purification methods. This review examines the advantages and disadvantages of various purification techniques alongside the heterogeneity they may introduce. We utilize the heterogeneity of BEVs as a framework to critically analyze the barriers to their application and the factors influencing their characteristics. Additionally, we constructively propose solutions to enhance the consistency of BEVs, thereby facilitating their further development and application.

Platelet backpacking nanoparticles based on bacterial outer membrane vesicles enhanced photothermal-immune anti-tumor therapy

Bacterial outer membrane vesicles (OMVs), produced by Gram-negative bacteria, retain the immunostimulatory capacity of parental bacteria. OMVs have been recognized as potent natural immune adjuvants and drug delivery vehicles. Photothermal therapy that triggers immunogenic cell death further stimulates the immune system by releasing damage-associated molecular patterns. This therapeutic effect can be synergized with OMVs to achieve enhanced anti-tumor outcomes. We also observed that tumors can recruit platelets. Leveraging the phenomenon, we have innovatively employed platelets as "couriers" to boost the tumor-targeting delivery efficiency of both OMVs and photothermal agents. In detail, based on OMVs, we meticulously engineered nanoparticles (IR780-SLN@O-P) with platelet-binding capacity. These "courier" platelets carry "cargo" IR780-SLN@O-P NPs to tumor sites via P-selectin, ensuring targeted delivery. Under laser irradiation, the photothermal agents generate significant photothermal effects, which combined with the immune-stimulating properties of OMVs, creating a robust anti-tumor immune response. For "cold" tumors such as triple-negative breast cancer (TNBC), our IR780-SLN@O-P NPs not only prolonged the survival of mice bearing 4T1 orthotopic tumors, but also significantly suppressed tumor growth. Moreover, they facilitated dendritic cell maturation and the infiltration of CD8+ T cells to ameliorate the immunosuppressive tumor environment. Our research aims to highlight the unique advantages of OMVs and explore the potential of the tumor-targeting strategy that synergizes photothermal therapy with immunotherapy. We hope that our findings can offer insights into TNBC clinical treatments.

Potential and development of cellular vesicle vaccines in cancer immunotherapy

Cancer vaccines are promising as an effective means of stimulating the immune system to clear tumors as well as to establish immune surveillance. In this paper, we discuss the main platforms and current status of cancer vaccines and propose a new cancer vaccine platform, the cytosolic vesicle vaccine. This vaccine has a unique structure that can integrate antigen and adjuvant carriers to improve the delivery efficiency and immune activation ability, which brings new ideas for cancer vaccine design. Tumor exosomes carry antigens and MHC-peptide complexes, which can provide tumor antigens to antigen-processing cells and increase the chances of recognition of tumor antigens by immune cells. DEVs play a role in amplifying the immune response by acting as carriers for the dissemination of antigenic substances in dendritic cells. OMVs, with their natural adjuvant properties, are one of the advantages for the preparation of antitumor vaccines. This paper presents the advantages of these three bacteria/extracellular vesicles as cancer vaccines and discusses the potential applications of functionally modified extracellular vesicles as cancer vaccines after cellular engineering or genetic engineering, as well as current clinical trials of extracellular vesicle vaccines. In summary, extracellular vesicle vaccines are a promising direction for cancer vaccine research.

Synthetic Vesicle-Based Drug Delivery Systems for Oral Disease Therapy: Current Applications and Future Directions

Oral diseases such as dental caries, periodontitis, and oral cancer are prevalent and present significant challenges to global public health. Although these diseases are typically treated through procedures like dental preparation and resin filling, scaling and root planning, or surgical excision, these interventions are often not entirely effective, and postoperative drug therapy is usually required. Traditional drug treatments, however, are limited by factors such as poor drug penetration, significant side effects, and the development of drug resistance. As a result, there is a growing need for novel drug delivery systems that can enhance therapeutic efficacy, reduce side effects, and improve treatment outcomes. In recent years, drug-loaded vesicles, such as liposomes, polymersomes, and extracellular vesicles (EVs), have emerged as promising drug delivery platforms due to their high drug encapsulation efficiency, controlled release properties, and excellent biocompatibility. This review provides an in-depth examination of the characteristics, advantages, and limitations of liposomes, polymersomes, and extracellular vesicles in the context of oral disease treatment. It further explores the reasons for their advantages and limitations and discusses the specific applications, development prospects, and strategies for optimizing these vesicle-based systems for improved clinical outcomes.

Innovative Strategies in Oncology: Bacterial Membrane Vesicle-Based Drug Delivery Systems for Cancer Diagnosis and Therapy

Outer membrane vesicles (OMVs) are double-layered structures of nanoscale lipids released by gram-negative bacteria. They have the same membrane composition and characteristics as primitive cells, which enables them to penetrate cells and tissues efficiently. These OMVs exhibit excellent membrane stability, immunogenicity, safety, and permeability (which makes it easier for them to penetrate into tumour tissue), making them suitable for developing cancer vaccines and drug delivery systems. Recent studies have focused on engineering OMVs to enhance tumour-targeting capabilities, reduce toxicity, and extend circulation time in vivo. This article reviews the latest progress in OMV engineering for tumour treatment and discusses the challenges associated with the use of OMV-based antitumour therapy in clinical practice.

Extracellular vesicles: From large-scale production and engineering to clinical applications

Extracellular vesicles (EVs) have emerged as a promising strategy for treating a wide spectrum of pathologies, as they can deliver their cargo to recipient cells and regulate the signaling pathway of these cells to modulate their fate. Despite the great potential of EVs in clinical applications, their low yield and the challenges of cargo loading remain significant obstacles, hindering their transition from experimental research to clinical practice. Therefore, promoting EV release and enhancing EV cargo-loading are promising fields with substantial research potential and broad application prospects. In this review, we summarize the clinical applications of EVs, the methods and technologies for their large-scale production, engineering, and modification, as well as the challenges that must be addressed during their development. We also discuss the future perspectives of this exciting field of research to facilitate its transformation from bench to clinical reality.

Utilizing Engineered Bacteria as "Cell Factories" In Vivo for Intracellular RNA-Loaded Outer Membrane Vesicles' Self-Assembly in Tumor Treatment

Delivery systems play a crucial role in RNA therapy. However, the current RNA delivery system involves complex preparation and transport processes, requiring RNA preassembly in vitro, transportation at low temperatures throughout, and possibly multiple injections for improved therapeutic efficacy. To address these challenges, we developed a simple and efficient RNA delivery system. This system only requires the injection of engineered bacteria, which serve as in vivo "cell factories" for continuous production of the target RNA. The RNA can self-assemble with engineered bacteria's outer membrane vesicles (OMVs), facilitating in vivo RNA delivery. Experimental results demonstrated that this system allowed effective delivery with excellent stability and continuity for various types of RNA, including mRNA, miRNA, and siRNA. And the relative abundance of target RNA in the OMVs was 104-107 times higher than that in the mock group. We took the delivery of PD-L1 siRNA for tumor treatment as an example and found that this system could effectively downregulate the gene expression of PD-L1 by approximately twofold. Notably, a single injection of engineered bacteria achieved a significant tumor suppression of 49.37% in vivo. This research provides promising insights into the RNA delivery system for tumor therapy.

Gene editing tool-loaded biomimetic cationic vesicles with highly efficient bacterial internalization for in vivo eradication of pathogens

In the post-COVID-19 era, drug-resistant bacterial infections emerge as one of major death causes, where multidrug-resistant Acinetobacter baumannii (MRAB) and drug-resistant Pseudomonas aeruginosa (DRPA) represent primary pathogens. However, the classical antibiotic strategy currently faces the bottleneck of drug resistance. We develop an antimicrobial strategy that applies the selective delivery of CRISPR/Cas9 plasmids to pathogens with biomimetic cationic hybrid vesicles (BCVs), irrelevant to bacterial drug resistance. CRISPR/Cas9 plasmids were constructed, replicating in MRAB or DRPA and expressing ribonucleic proteins, leading to irreparable chromosomal lesions; however, delivering the negatively charged plasmids with extremely large molecular weight to the pathogens at the infection site became a huge challenge. We found that the BCVs integrating the bacterial out membrane vesicles and cationic lipids efficiently delivered the plasmids in vitro/in vivo to the pathogens followed by effective internalization. The BCVs were used by intratracheal or topical hydrogel application against MRAB pulmonary infection or DRPA wound infection, and both of the two pathogens were eradicated from the lung or the wound. CRISPR/Cas9 plasmid-loaded BCVs become a promising medication for drug-resistant bacteria infections.

Outer Membrane Vesicle-Cancer Hybrid Membrane Coating Indocyanine Green Nanoparticles for Enhancing Photothermal Therapy Efficacy in Tumors

Cell membrane-coated nanomaterials are increasingly recognized as effective in cancer treatment due to their unique benefits. This study introduces a novel hybrid membrane coating nanoparticle, termed cancer cell membrane (CCM)-outer membrane vesicle (OMV)@Lip-indocyanine green (ICG), which combines CCMs with bacterial OMV to encapsulate ICG-loaded liposomes. Comprehensive analyses were conducted to assess its physical and chemical properties as well as its functionality. Demonstrating targeted delivery capabilities and good biocompatibility, CCM-OMV@Lip-ICG nanoparticles showed promising photothermal and immunotherapeutic effects in tumor models. By inducing hyperthermia-induced tumor therapy and bolstering antitumor immunity, CCM-OMV@Lip-ICG nanoparticles exhibit a synergistic therapeutic effect, providing a new perspective for the management of cancer.

Advancements in Nanoparticle-Based Strategies for Enhanced Antibacterial Interventions

The escalating global threat of antibiotic resistance underscores the urgent need for innovative antimicrobial strategies. This review explores the cutting-edge applications of nanotechnology in combating bacterial infections, addressing a critical healthcare challenge. We critically assess the antimicrobial properties and mechanisms of diverse nanoparticle systems, including liposomes, polymeric micelles, solid lipid nanoparticles, dendrimers, zinc oxide, silver, and gold nanoparticles, as well as nanoencapsulated essential oils. These nanomaterials offer distinct advantages, such as enhanced drug delivery, improved bioavailability, and efficacy against antibiotic-resistant strains. Recent advancements in nanoparticle synthesis, functionalization, and their synergistic interactions with conventional antibiotics are highlighted. The review emphasizes biocompatibility considerations, stressing the need for rigorous safety assessments in nanomaterial applications. By synthesizing current knowledge and identifying emerging trends, this review provides crucial insights for researchers and clinicians aiming to leverage nanotechnology for next-generation antimicrobial therapies. The integration of nanotechnology represents a promising frontier in combating infectious diseases, underscoring the timeliness and imperative of this comprehensive analysis.

Recent advances in bacterial outer membrane vesicles: Effects on the immune system, mechanisms and their usage for tumor treatment

Tumor treatment remains a significant medical challenge, with many traditional therapies causing notable side effects. Recent research has led to the development of immunotherapy, which offers numerous advantages. Bacteria inherently possess motility, allowing them to preferentially colonize tumors and modulate the tumor immune microenvironment, thus influencing the efficacy of immunotherapy. Bacterial outer membrane vesicles (OMVs) secreted by gram-negative bacteria are nanoscale lipid bilayer structures rich in bacterial antigens, pathogen-associated molecular patterns (PAMPs), various proteins, and vesicle structures. These features allow OMVs to stimulate immune system activation, generate immune responses, and serve as efficient drug delivery vehicles. This dual capability enhances the effectiveness of immunotherapy combined with chemotherapy or phototherapy, thereby improving anticancer drug efficacy. Current research has concentrated on engineering OMVs to enhance production yield, minimize cytotoxicity, and improve the safety and efficacy of treatments. Consequently, OMVs hold great promise for applications in tumor immunotherapy, tumor vaccine development, and drug delivery. This article provides an overview of the structural composition and immune mechanisms of OMVs, details various OMVs modification strategies, and reviews the progress in using OMVs for tumor treatment and their anti-tumor mechanisms. Additionally, it discusses the challenges faced in translating OMV-based anti-tumor therapies into clinical practice, aiming to provide a comprehensive understanding of OMVs' potential for in-depth research and clinical application.

Novel Nano Drug-Loaded Hydrogel Coatings for the Prevention and Treatment of CAUTI

Catheter-associated urinary tract infection (CAUTI) is a prevalent type of hospital-acquired infection, affecting approximately 15% to 25% of patients with urinary catheters. Long-term use of the catheter can lead to colonization of microorganisms and biofilm formation, and may develop into bacterial CAUTI. However, the frequent replacement of catheters in clinical settings can result in tissue damage, inflammation, ulceration, and additional complications, causing discomfort and pain for patients. In light of these challenges, a novel nanodrug-supported hydrogel coating called NP-AM/FK@OMV-P/H has been developed in this study. Through in vitro experiments, it is confirmed that OMV nano-loaded liquid gel coating has an effective reaction against E.coli HAase and releases antibacterial drugs. This coating has also demonstrated strong inhibition of E.coli and has shown the ability to inhibit the formation of bacterial biofilm. These findings highlight the potential of the OMV nanoparticle gel coating in preventing and treating bacterial infections. Notably, NP-AM/FK@OMV-P/H has exhibited greater efficacy against multidrug-resistant E.coli associated with UTIs compared to coatings containing single antimicrobial peptides or antibiotics. Additionally, it has demonstrated good biosecurity. In conclusion, the NP-AM/FK@OMV-P/H coating holds great potential in providing benefits to patients with CAUTI.

The two coin sides of bacterial extracellular membrane nanovesicles: atherosclerosis trigger or remedy

Among the numerous driving forces that cause the atherosclerotic cardiovascular disease (ASCVD), pathogenic bacterial extracellular membrane nanovesicles (BEMNs) containing toxins and virulence factors appear to be the key trigger of inflammation and atherogenesis, the major processes involved in the pathogenesis of ASCVD. Since BEMNs are the carriers of nanosized biomolecules to distant sites, they are now being considered as a novel drug delivery system. Nowadays, many therapeutic strategies are used to treat ASCVD. However, the conventional anti-atherosclerotic therapies are not effective enough. This primarily due to the inefficiency of non-targeted drug delivery systems to tissue affected areas, which, in turn, leads to numerous side effects, as well as faulty pharmacokinetics. In this regard, nanomedicine methods using nanoparticles (NPs) as targeted drug delivery vehicles proved to be extremely useful. Bioengineered BEMNs equipped with disease-specific ligand moieties and loaded with corresponding drugs represent a promising tool in nanomedicine, which can be used as a novel drug delivery system for a successful therapy of ASCVD. In this review, we outline the involvement of pathogenic BEMNs in the triggering of ASCVD, the conventional therapeutic strategies for the treatment of ASCVD, and the recent trends in nanomedicine using BEMNs and NPs as a vehicle for targeted drug delivery.

Natural compounds-based nanomedicines for cancer treatment: Future directions and challenges

Several efforts have been extensively accomplished for the amelioration of the cancer treatments using different types of new drugs and less invasives therapies in comparison with the traditional therapeutic modalities, which are widely associated with numerous drawbacks, such as drug resistance, non-selectivity and high costs, restraining their clinical response. The application of natural compounds for the prevention and treatment of different cancer cells has attracted significant attention from the pharmaceuticals and scientific communities over the past decades. Although the use of nanotechnology in cancer therapy is still in the preliminary stages, the application of nanotherapeutics has demonstrated to decrease the various limitations related to the use of natural compounds, such as physical/chemical instability, poor aqueous solubility, and low bioavailability. Despite the nanotechnology has emerged as a promise to improve the bioavailability of the natural compounds, there are still limited clinical trials performed for their application with various challenges required for the pre-clinical and clinical trials, such as production at an industrial level, assurance of nanotherapeutics long-term stability, physiological barriers and safety and regulatory issues. This review highlights the most recent advances in the nanocarriers for natural compounds secreted from plants, bacteria, fungi, and marine organisms, as well as their role on cell signaling pathways for anticancer treatments. Additionally, the clinical status and the main challenges regarding the natural compounds loaded in nanocarriers for clinical applications were also discussed.

Unveiling the promise: Exosomes as game-changers in anti-infective therapy

Extracellular vesicles (EVs)-based intercellular communication (through exosomes, microvesicles, and apoptotic bodies) is conserved across all kingdoms of life. In recent years, exosomes have gained much attention for targeted pharmaceutical administration due to their unique features, nanoscale size, and capacity to significantly contribute to cellular communication. As drug delivery vehicles, exosomes have several advantages over alternative nanoparticulate drug delivery technologies. A key advantage lies in their comparable makeup to the body's cells, which makes them non-immunogenic. However, exosomes vesicles face several challenges, including a lack of an effective and standard production technique, decreased drug loading capacity, limited characterization techniques, and underdeveloped isolation and purification procedures. Exosomes are well known for their long-term safety and natural ability to transport intercellular nucleic acids and medicinal compounds across the blood-brain-barrier (BBB). Therefore, in addition to revealing new insights into exosomes' distinctiveness, the growing availability of new analytical tools may drive the development of next-generation synthetic systems. Herein, light is shed on exosomes as drug delivery vehicles in anti-infective therapy by reviewing the literature on primary articles published between 2002 and 2023. Additionally, the benefits and limitations of employing exosomes as vehicles for therapeutic drug delivery are also discussed.

Opportunities for Helicobacter pylori Eradication beyond Conventional Antibiotics

Helicobacter pylori (H. pylori) is a bacterium known to be associated with a significant risk of gastric cancer in addition to chronic gastritis, peptic ulcer, and MALT lymphoma. Although only a small percentage of patients infected with H. pylori develop gastric cancer, Gastric cancer causes more than 750,000 deaths worldwide, with 90% of cases being caused by H. pylori. The eradication of this bacterium rests on multiple drug regimens as guided by various consensus. However, the efficacy of empirical therapy is decreasing due to antimicrobial resistance. In addition, biofilm formation complicates eradication. As the search for new antibiotics lags behind the bacterium's ability to mutate, studies have been directed toward finding new anti-H. pylori agents while also optimizing current drug functions. Targeting biofilm, repurposing outer membrane vesicles that were initially a virulence factor of the bacteria, phage therapy, probiotics, and the construction of nanoparticles might be able to complement or even be alternatives for H. pylori treatment. This review aims to present reports on various compounds, either new or combined with current antibiotics, and their pathways to counteract H. pylori resistance.

Novel quinazolin-6-yl Isoindolinone: Altering polysaccharide chemstructure for antibacterial efficacy against Staphylococcus aureus

The ongoing development of novel strategies to combat Staphylococcus aureus and eliminate its biofilm formation has gained significant attention for human health. Antibiotic-resistant S. aureus necessitates the development of novel antibacterial agents with new mechanism of action. This study introduced a promising recently synthesized quinazolin-6-yl isoindolinone (IQE-X1), which exhibited potent antibacterial and antibiofilm efficacy with average median inhibitory concentration (IC50) of 3.37 μg mL-1 and minimal inhibitory concentration (MIC) of 12.5 μg mL-1, coupled with its ability to reduce cell surface hydrophobicity. IQE-X1 dose-dependently decreased extracellular polysaccharides (EPS) and its component monosaccharides, including rhamnose, arabinose, glucosamine, galactose, glucose, xylose, mannose, and ribose, accompanied by an increase in capsular polysaccharides (CP) and its individual monosaccharides, especially glucosamine. IQE-X1 demonstrated specificity in modulating the structural profiles of EPS and CP by altering the compositional ratios of their component monosaccharides. The potential mechanism of polysaccharide modulation was preliminarily elucidated through the response of β-N-acetylaminoglucosidase to IQE-X1 and their direct binding interaction. These findings provide new insights into the potential manipulation of the chemstructure of these biologically important macromolecules, EPS and CP, and highlight the antibacterial potential of IQE-X1 as a polysaccharide modulator for the development of more effective polysaccharide-targeted strategies against S. aureus.

Engineering Versatile Bacteria-Derived Outer Membrane Vesicles: An Adaptable Platform for Advancing Cancer Immunotherapy

In recent years, cancer immunotherapy has undergone a transformative shift toward personalized and targeted therapeutic strategies. Bacteria-derived outer membrane vesicles (OMVs) have emerged as a promising and adaptable platform for cancer immunotherapy due to their unique properties, including natural immunogenicity and the ability to be engineered for specific therapeutic purposes. In this review, a comprehensive overview is provided of state-of-the-art techniques and methodologies employed in the engineering of versatile OMVs for cancer immunotherapy. Beginning by exploring the biogenesis and composition of OMVs, unveiling their intrinsic immunogenic properties for therapeutic appeal. Subsequently, innovative approaches employed to engineer OMVs are delved into, ranging from the genetic engineering of parent bacteria to the incorporation of functional molecules. The importance of rational design strategies is highlighted to enhance the immunogenicity and specificity of OMVs, allowing tailoring for diverse cancer types. Furthermore, insights into clinical studies and potential challenges utilizing OMVs as cancer vaccines or adjuvants are also provided, offering a comprehensive assessment of the current landscape and future prospects. Overall, this review provides valuable insights for researchers involved in the rapidly evolving field of cancer immunotherapy, offering a roadmap for harnessing the full potential of OMVs as a versatile and adaptable platform for cancer treatment.

Roseburia intestinalis-derived extracellular vesicles ameliorate colitis by modulating intestinal barrier, microbiome, and inflammatory responses

Inflammatory bowel disease (IBD) is a chronic disorder characterized by recurrent gastrointestinal inflammation, lacking a precise aetiology and definitive cure. The gut microbiome is vital in preventing and treating IBD due to its various physiological functions. In the interplay between the gut microbiome and human health, extracellular vesicles secreted by gut bacteria (BEVs) are key mediators. Herein, we explore the role of Roseburia intestinalis (R)-derived EVs (R-EVs) as potent anti-inflammatory mediators in treating dextran sulfate sodium-induced colitis. R was selected as an optimal BEV producer for IBD treatment through ANCOM analysis. R-EVs with a 76 nm diameter were isolated from R using a tangential flow filtration system. Orally administered R-EVs effectively accumulated in inflamed colonic tissues and increased the abundance of Bifidobacterium on microbial changes, inhibiting colonic inflammation and prompting intestinal recovery. Due to the presence of Ile-Pro-Ile in the vesicular structure, R-EVs reduced the DPP4 activity in inflamed colonic tissue and increased the active GLP-1, thereby downregulating the NFκB and STAT3 via the PI3K pathway. Our results shed light on the impact of BEVs on intestinal recovery and gut microbiome alteration in treating IBD.

Harnessing and Mimicking Bacterial Features to Combat Cancer: From Living Entities to Artificial Mimicking Systems

Bacterial-derived micro-/nanomedicine has garnered considerable attention in anticancer therapy, owing to the unique natural features of bacteria, including specific targeting ability, immunogenic benefits, physicochemical modifiability, and biotechnological editability. Besides, bacterial components have also been explored as promising drug delivery vehicles. Harnessing these bacterial features, cutting-edge physicochemical and biotechnologies have been applied to attenuated tumor-targeting bacteria with unique properties or functions for potent and effective cancer treatment, including strategies of gene-editing and genetic circuits. Further, the advent of bacteria-inspired micro-/nanorobots and mimicking artificial systems has furnished fresh perspectives for formulating strategies for developing highly efficient drug delivery systems. Focusing on the unique natural features and advantages of bacteria, this review delves into advances in bacteria-derived drug delivery systems for anticancer treatment in recent years, which has experienced a process from living entities to artificial mimicking systems. Meanwhile, a summary of relative clinical trials is provided and primary challenges impeding their clinical application are discussed. Furthermore, future directions are suggested for bacteria-derived systems to combat cancer.

Bacteria extracellular vesicle as nanopharmaceuticals for versatile biomedical potential

Bacteria extracellular vesicles (BEVs), characterized as the lipid bilayer membrane-surrounded nanoparticles filled with molecular cargo from parent cells, play fundamental roles in the bacteria growth and pathogenesis, as well as facilitating essential interaction between bacteria and host systems. Notably, benefiting from their unique biological functions, BEVs hold great promise as novel nanopharmaceuticals for diverse biomedical potential, attracting significant interest from both industry and academia. Typically, BEVs are evaluated as promising drug delivery platforms, on account of their intrinsic cell-targeting capability, ease of versatile cargo engineering, and capability to penetrate physiological barriers. Moreover, attributing to considerable intrinsic immunogenicity, BEVs are able to interact with the host immune system to boost immunotherapy as the novel nanovaccine against a wide range of diseases. Towards these significant directions, in this review, we elucidate the nature of BEVs and their role in activating host immune response for a better understanding of BEV-based nanopharmaceuticals' development. Additionally, we also systematically summarize recent advances in BEVs for achieving the target delivery of genetic material, therapeutic agents, and functional materials. Furthermore, vaccination strategies using BEVs are carefully covered, illustrating their flexible therapeutic potential in combating bacterial infections, viral infections, and cancer. Finally, the current hurdles and further outlook of these BEV-based nanopharmaceuticals will also be provided.

Tailoring therapeutics via a systematic beneficial elements comparison between photosynthetic bacteria-derived OMVs and extruded nanovesicles

Photosynthetic bacteria (PSB) has shown significant potential as a drug or drug delivery system owing to their photothermal capabilities and antioxidant properties. Nevertheless, the actualization of their potential is impeded by inherent constraints, including their considerable size, heightened immunogenicity and compromised biosafety. Conquering these obstacles and pursuing more effective solutions remains a top priority. Similar to extracellular vesicles, bacterial outer membrane vesicles (OMVs) have demonstrated a great potential in biomedical applications. OMVs from PSB encapsulate a rich array of bioactive constituents, including proteins, nucleic acids, and lipids inherited from their parent cells. Consequently, they emerge as a promising and practical alternative. Unfortunately, OMVs have suffered from low yield and inconsistent particle sizes. In response, bacteria-derived nanovesicles (BNVs), created through controlled extrusion, adeptly overcome the challenges associated with OMVs. However, the differences, both in composition and subsequent biological effects, between OMVs and BNVs remain enigmatic. In a groundbreaking endeavor, our study meticulously cultivates PSB-derived OMVs and BNVs, dissecting their nuances. Despite minimal differences in morphology and size between PSB-derived OMVs and BNVs, the latter contains a higher concentration of active ingredients and metabolites. Particularly noteworthy is the elevated levels of lysophosphatidylcholine (LPC) found in BNVs, known for its ability to enhance cell proliferation and initiate downstream signaling pathways that promote angiogenesis and epithelialization. Importantly, our results indicate that BNVs can accelerate wound closure more effectively by orchestrating a harmonious balance of cell proliferation and migration within NIH-3T3 cells, while also activating the EGFR/AKT/PI3K pathway. In contrast, OMVs have a pronounced aptitude in anti-cancer efforts, driving macrophages toward the M1 phenotype and promoting the release of inflammatory cytokines. Thus, our findings not only provide a promising methodological framework but also establish a definitive criterion for discerning the optimal application of OMVs and BNVs in addressing a wide range of medical conditions.

Proteome analysis of outer membrane vesicles from Vibrio parahaemolyticus causing acute hepatopancreatic necrosis disease

A specific strain of Vibrio parahaemolyticus (VpAHPND) causes acute hepatopancreatic necrosis disease (AHPND), leading to significant losses in shrimp aquaculture. Outer membrane vesicles (OMVs) are naturally secreted by Gram-negative bacteria, and their significant roles in host-pathogen interactions and pathogenicity have been recognized. In the present study, OMVs were isolated from VpAHPND by differential-ultracentrifugation and used for proteomics analysis. In the Nano-HPLC-MS/MS analysis, totally 645 proteins were determined, including virulence factors, immunogenic proteins, outer membrane protein, bacterial secretory proteins, ribosomal proteins, protease, and iron regulation proteins. Furthermore, GO and KEGG annotations indicated that proteins identified in VpAHPND-OMVs are involved in metabolism, regulation of multiple biological processes, genetic information processes, immunity and more. Meanwhile, toxin proteins PirAvp and PirBvp, associated with VpAHPND pathogenicity, were also identified in the proteome of VpAHPND-OMVs. Our objective is to identify the protein composition of OMVs released by VpAHPND, analyzing the potential for cytotoxicity and immunomodulatory activity of these granule hosts. This study is crucial for understanding the roles played by bacterial-derived vesicles in the disease process, given that these vesicles carry relevant activities inherent to the bacteria that produce them.

Extracellular vesicles derived from plasmodium-infected red blood cells alleviate cerebral malaria in plasmodium berghei ANKA-infected C57BL/6J mice

RTS,S is the first malaria vaccine recommended for implementation among young children at risk. However, vaccine efficacy is modest and short-lived. To mitigate the risk of cerebral malaria (CM) among children under the age of 5, it is imperative to develop new vaccines. EVs are potential vaccine candidates as they obtain the ability of brain-targeted delivery and transfer plasmodium antigens and immunomodulators during infections. This study extracted EVs from BALB/c mice infected with Plasmodium yoelii 17XNL (P.y17XNL). C57BL/6J mice were intravenously immunized with EVs (EV-I.V. + CM group) or subcutaneously vaccinated with the combination of EVs and CpG ODN-1826 (EV + CPG ODN-S.C. + CM group) on days 0 and 20, followed by infection with Plasmodium berghei ANKA (P.bANKA) on day 20 post-second immunization. We monitored Parasitemia and survival rate. The integrity of the Blood-brain barrier (BBB) was examined using Evans blue staining.The levels of cytokines and adhesion molecules were evaluated using Luminex, RT-qPCR, and WB. Brain pathology was evaluated by hematoxylin and eosin and immunohistochemical staining. The serum levels of IgG, IgG1, and IgG2a were analyzed by enzyme-linked immunosorbent assay. Compared with those in the P.bANKA-infected group, parasitemia increased slowly, death was delayed (day 10 post-infection), and the survival rate reached 75 %-83.3 % in the EV-I.V. + ECM and EV + CPG ODN-S.C. + ECM groups. Meanwhile, compared with the EV + CPG ODN-S.C. + ECM group, although parasitemia was almost the same, the survival rate increased in the EV-I.V. + ECM group.Additionally, EVs immunization markedly downregulated inflammatory responses in the spleen and brain and ameliorated brain pathological changes, including BBB disruption and infected red blood cell (iRBC) sequestration. Furthermore, the EVs immunization group exhibited enhanced antibody responses (upregulation of IgG1 and IgG2a production) compared to the normal control group. EV immunization exerted protective effects, improving the integrity of the BBB, downregulating inflammation response of brain tissue, result in reduces the incidence of CM. The protective effects were determined by immunological pathways and brain targets elicited by EVs. Intravenous immunization exhibited better performance than subcutaneous immunization, which perhaps correlated with EVs, which can naturally cross BBB to play a better role in brain protection.

Bacterial extracellular vesicles: biotechnological perspective for enhanced productivity

Bacterial extracellular vesicles (BEVs) are non-replicative nanostructures released by Gram-negative and Gram-positive bacteria as a survival mechanism and inter- and intraspecific communication mechanism. Due to BEVs physical, biochemical, and biofunctional characteristics, there is interest in producing and using them in developing new therapeutics, vaccines, or delivery systems. However, BEV release is typically low, limiting their application. Here, we provide a biotechnological perspective to enhance BEV production, highlighting current strategies. The strategies include the production of hypervesiculating strains through gene modification, bacteria culture under stress conditions, and artificial vesicles production. We discussed the effect of these production strategies on BEVs types, morphology, composition, and activity. Furthermore, we summarized general aspects of BEV biogenesis, functional capabilities, and applications, framing their current importance and the need to produce them in abundance. This review will expand the knowledge about the range of strategies associated with BEV bioprocesses to increase their productivity and extend their application possibilities.

Expert opinion on antimicrobial therapies: is there enough scientific evidence to state that targeted therapies outperform non-targeted ones?

INTRODUCTION

Different active and passive strategies have been developed to fight against pathogenic bacteria. Those actions are undertaken to reduce the bacterial burden while minimizing the possibilities to develop not only antimicrobial resistance but also antimicrobial side-effects such as allergic or hypersensitivity reactions.

AREAS COVERED

We have reviewed preclinical results that evidence that targeted antimicrobial therapies outperform non-targeted ones. Active selective targeting against pathogenic bacteria has been achieved through the functionalization of antimicrobials, either alone or encapsulated within micro- or nanocarriers, with various recognition moieties. These moieties include peptides, aptamers, antibodies, carbohydrates, extracellular vesicles, cell membranes, infective agents, and other affinity ligands with specific bacterial tropism. Those selective ligands increase retention and enhance effectiveness reducing the side-effects and the required dose to exert the antimicrobial action at the site of infection.

EXPERT OPINION

When using targeted antimicrobial therapies not only reduced side-effects are observed, but also, compared to the administration of equivalent doses of the non-targeted drugs, a superior efficacy has been demonstrated against planktonic, sessile, and intracellular pathogenic bacterial persisters. The translation of those targeted therapies to subsequent phases of clinical development still requires the demonstration of a reduction in the probabilities for the pathogen to develop resistance when using targeted approaches.

Bacterial membrane vesicles: orchestrators of interkingdom interactions in microbial communities for environmental adaptation and pathogenic dynamics

Bacterial membrane vesicles (MVs) have attracted increasing attention due to their significant roles in bacterial physiology and pathogenic processes. In this review, we provide an overview of the importance and current research status of MVs in regulating bacterial physiology and pathogenic processes, as well as their crucial roles in environmental adaptation and pathogenic infections. We describe the formation mechanism, composition, structure, and functions of MVs, and discuss the various roles of MVs in bacterial environmental adaptation and pathogenic infections. Additionally, we analyze the limitations and challenges of MV-related research and prospect the potential applications of MVs in environmental adaptation, pathogenic mechanisms, and novel therapeutic strategies. This review emphasizes the significance of understanding and studying MVs for the development of new insights into bacterial environmental adaptation and pathogenic processes. Overall, this review contributes to our understanding of the intricate interplay between bacteria and their environment and provides valuable insights for the development of novel therapeutic strategies targeting bacterial pathogenicity.

Biomimetic Hydrogel Containing Copper Sulfide Nanoparticles and Deferoxamine for Photothermal Therapy of Infected Diabetic Wounds

Inducing cell migration from the edges to the center of a wound, promoting angiogenesis, and controlling bacterial infection are very important for diabetic wound healing. Incorporating growth factors and antibiotics into hydrogels for wound dressing is considered a potential strategy to meet these requirements. However, some present drawbacks greatly slow down their development toward application, such as the short half-life and high price of growth factors, low antibiotic efficiency against drug-resistant bacteria, insufficient ability of hydrogels to promote cell migration, etc. Deferoxamine (DFO) can upregulate the expression of HIF-1α, thus stimulating the secretion of angiogenesis-related endogenous growth factors. Copper sulfide (CuS) nanoparticles possess excellent antibacterial performance combined with photothermal therapy (PTT). Herein, DFO and CuS nanoparticles are incorporated into a biomimetic hydrogel, which mimics the structure and function of the extracellular matrix (ECM), abbreviated as DFO/CuS-ECMgel. This biomimetic hydrogel is expected to be able to promote cell adhesion and migration, be degraded by cell-secreted matrix metalloproteinases (MMPs), and then release DFO and CuS nanoparticles at the wound site to exert their therapeutic effects. As a result, the three crucial requirements for diabetic wound healing, "beneficial for cell adhesion and migration, promoting angiogenesis, effectively killing drug-resistant bacteria," can be achieved simultaneously.

Reversing the Natural Drug Resistance of Gram-Negative Bacteria to Fusidic Acid via Forming Drug-Phospholipid Complex

Drug resistance substantially compromises antibiotic therapy and poses a serious threat to public health. Fusidic acid (FA) is commonly used to treat staphylococcal infections, such as pneumonia, osteomyelitis and skin infections. However, Gram-negative bacteria have natural resistance to FA, which is almost restrained in cell membranes due to the strong interactions between FA and phospholipids. Herein, we aim to utilize the strong FA-phospholipid interaction to pre-form a complex of FA with the exogenous phospholipid. The FA, in the form of an FA-phospholipid complex (FA-PC), no longer interacts with the endogenous membrane phospholipids and thus can be delivered into bacteria cells successfully. We found that the water solubility of FA (5 µg/mL) was improved to 133 µg/mL by forming the FA-PC (molar ratio 1:1). Furthermore, upon incubation for 6 h, the FA-PC (20 µg/mL) caused a 99.9% viability loss of E. coli and 99.1% loss of P. aeruginosa, while free FA did not work. The morphology of the elongated bacteria cells after treatment with the FA-PC was demonstrated by SEM. The successful intracellular delivery was shown by confocal laser scanning microscopy in the form of coumarin 6-PC (C6-PC), where C6 served as a fluorescent probe. Interestingly, the antibacterial effect of the FA-PC was significantly compromised by adding extra phospholipid in the medium, indicating that there may be a phospholipid-based transmembrane transport mechanism underlying the intracellular delivery of the FA-PC. This is the first report regarding FA-PC formation and its successful reversing of Gram-negative bacteria resistance to FA, and it provides a platform to reverse transmembrane delivery-related drug resistance. The ready availability of phospholipid and the simple preparation allow it to have great potential for clinical use.

Maintaining sidedness and fluidity in cell membrane coatings supported on nano-particulate and planar surfaces

Supported cell membrane coatings meet many requirements set to bioactive nanocarriers and materials, provided sidedness and fluidity of the natural membrane are maintained upon coating. However, the properties of a support-surface responsible for maintaining correct sidedness and fluidity are unknown. Here, we briefly review the properties of natural membranes and membrane-isolation methods, with focus on the asymmetric distribution of functional groups in natural membranes (sidedness) and the ability of molecules to float across a membrane to form functional domains (fluidity). This review concludes that hydrophilic sugar-residues of glycoproteins in the outer-leaflet of cell membranes direct the more hydrophobic inner-leaflet towards a support-surface to create a correctly-sided membrane coating, regardless of electrostatic double-layer interactions. On positively-charged support-surfaces however, strong, electrostatic double-layer attraction of negatively-charged membranes can impede homogeneous coating. In correctly-sided membrane coatings, fluidity is maintained regardless of whether the surface carries a positive or negative charge. However, membranes are frozen on positively-charged, highly-curved, small nanoparticles and localized nanoscopic structures on a support-surface. This leaves an unsupported membrane coating in between nanostructures on planar support-surfaces that is in dual-sided contact with its aqueous environment, yielding enhanced fluidity in membrane coatings on nanostructured, planar support-surfaces as compared with smooth ones.

Current advances in bacteria-based cancer immunotherapy

As the understanding of the tumor microenvironment has deepened, immunotherapy has become a promising strategy for cancer treatment. In contrast to traditional therapies, immunotherapy is more precise and induces fewer adverse effects. In this field, some bacteria have attracted increased attention because of their natural ability to preferentially colonize and proliferate inside tumor sites and exert antitumor effects. Moreover, bacterial components may activate innate and adaptive immunity to resist tumor progression. However, the application of bacteria-based cancer immunotherapy is hampered by potential infection-associated toxicity and unpredictable behavior in vivo. Owing to modern developments in genetic engineering, bacteria can be modified to weaken their toxicity and enhance their ability to eliminate tumor cells or activate the antitumor immune response. This review summarizes the roles of bacteria in the tumor microenvironment, current strategies for bacterial engineering, and the synergistic efficiency of bacteria with other immunotherapies. In addition, the prospects and challenges of the clinical translation of engineered bacteria are summarized.