Engineered probiotics biofilm enhances osseointegration via immunoregulation and anti-infection

Janus PEGylated CuS-engineered Lactobacillus casei combats biofilm infections via metabolic interference and innate immunomodulation

Bacterial implant-associated infections predominantly contribute to the failure of prosthesis implantation. The local biofilm microenvironment (BME), characterized by its hyperacidic condition and high hydrogen peroxide (H2O2) level, inhibits the host's immune response, thereby facilitating recurrent infections. Here, a Janus PEGylated CuS nanoparticle (CuPen) armed engineered Lactobacillus casei (L. casei) denoted as LC@CuPen, is proposed to interfere with bacterial metabolism and arouse macrophage antibiofilm function. Once LC@CuPen reached the BME, NIR irradiation-activated mild heat damages L. casei and biofilm structure. Meanwhile, the BME-responsive LC@CuPen can catalyze local H2O2 to produce toxic •OH, whereas in normal tissues, the effect of •OH production is greatly reduced due to the higher pH and lower H2O2 concentration. The released bacteriocin from damaged L. casei can destroy the bacterial membrane to enhance the penetration of •OH into damaged biofilm. Excessive •OH interferes with normal bacterial metabolism, resulting in reduced resistance of bacteria to heat stress. Finally, under the action of mild heat treatment, the bacterial biofilm lysed and died. Furthermore, the pathogen-associated molecular patterns (PAMPs) in LC@CuPen can induce M1 polarization of macrophages through NF-κB pathway and promote the release of inflammatory factors. Inflammatory factors enhance the migration of macrophages to the site of infection and phagocytose bacteria, thereby inhibiting the recurrence of infection. Generally, this engineered L. casei program presents a novel perspective for the treatment of bacterial implant-associated infections and serves as a valuable reference for future clinical applications of engineered probiotics.

Probiotic biofilm modified bioceramics for bone defect healing via osteogenesis, angiogenesis, and immune modulation

The failure to repair bone defects in a timely manner has a detrimental effect on patients' quality of life and functional status. Consequently, there are increasing demands for medical interventions to promote healing of bone defects. However, the local inflammation induced by implants and the side effects associated with the systemic use of drugs have prompted research into the development of bioactive materials. Recent reports have indicated that oral administration of Lactobacillus acidophilus (LA) can act as an immunomodulator. In this study, we have strategically designed bioceramic scaffolds modified with inactivated LA biofilms (LA@BC) through UV irradiation for localized application of LA. The biosafety of the scaffold was validated at the cellular and animal levels to ensure that it can be safely used without bacteraemia. LA@BC achieved M1 to M2 polarization of macrophages in vitro by reducing the secretion of inflammatory factors. In addition, LA@BC enhanced the osteogenic effect of bone marrow mesenchymal stem cells by modulating the Wnt/β-catenin signaling pathway. Furthermore, osteogenesis and angiogenesis complement each other. LA@BC exerted a positive effect on the angiogenic effect of endothelial cells. In a rat cranial defect model, LA@BC upregulated the expression of RUNX2, OCN, CD31, and IL-10 in tissues, again demonstrating potent immunomodulatory and osteogenic effects. In conclusion, this bioactive scaffold provides a new strategy for clinical bone repair.

Natural, safety immunomodulatory derivatives of lactobacillus biofilms promote diabetic wound healing by metabolically regulating macrophage phenotype and alleviating local inflammation

INTRODUCTION

Long-term inflammatory microenvironment further impairs the healing process of diabetic wounds. Many studies have shown that Lactobacillus can regulate immune function and promote injured tissue repair. However, the immunomodulatory function and safety of Lactobacillus biofilm (LB) on wounds need further investigation.

OBJECTIVES

In this present research, we proposed a "bacteria-free biofilm derivative therapy" and successfully extracted Lactobacillus biofilm derivatives (LBDs) by ultrasonic separation and filtration technology for the natural and safe treatment of diabetic wounds.

METHODS

The study first cultured Lactobacillus anaerobically and extracted LBDs using ultrasound separation combined with filtration technology. LBDs were characterized via scanning electron microscopy, Concanavalin A fluorescence staining, and protein gel electrophoresis. In vivo diabetic wound model, wound closure rates were dynamically monitored, and tissue sections were analyzed using hematoxylin-eosin and immunofluorescence staining to evaluate LBDs' healing effects. An in vitro macrophage inflammation model was established, employing immunofluorescence, flow cytometry, and Western blotting techniques to explore the molecular mechanisms underlying LBDs' effects on macrophage phenotypes. Furthermore, whole-genome sequencing and proteomics of LBDs-treated macrophages were performed to further elucidate the intrinsic molecular mechanisms through which LBDs regulate macrophage phenotypes.

RESULTS

LBDs were effectively extracted utilizing ultrasonic separation coupled with filtration technology. Studies revealed that LBDs modulate the systemic metabolic reprogramming in wound-site macrophages, suppress JAK-STAT1 signaling pathway, alleviate the local inflammatory microenvironment, promote neovascularization and ultimately accelerate wound healing.

CONCLUSION

The LBDs retains most bioactive components of the LB. As a natural, safe and immunomodulatory agent, LBDs promote diabetic wound healing by metabolically reprogramming macrophage phenotypes and improving the local immune microenvironment, offering promising potential for regenerative applications in diabetic wound management.

Engineered bacillus subtilis enhances bone regeneration via immunoregulation and anti-Infection

Chronic osteomyelitis caused by implant infections is a common complication following orthopedic surgery. Preventing bacterial infection and simultaneously improving bone regeneration are the key for osteomyelitis. Current treatments include systemic antibiotics and multiple surgical interventions, but the strategies available for treatment are limited. In this study, a multifunctional engineered Bacillus subtilis (B. sub) hydrogel with sulfasalazine (SSZ) is developed to treat methicillin-resistant Staphylococcus aureus (MRSA) infection and anti-inflammatory and promote bone regeneration. B. sub in alginate hydrogels protects B. sub from being cleared by the host immune system while allowing the release of its bioactive substances, including antibacterial peptides and anti-inflammatory agents such as SSZ. The results show that the engineered probiotic hydrogels exhibit excellent antibacterial efficacy against MRSA (97 %) and prevent the development of bacterial resistance. The antibacterial effect is primarily mediated through the secretion of bioactive peptides by B. sub, which not only inhibit MRSA growth but also reduce the likelihood of resistance development. Meanwhile, the probiotic hydrogel has a greater ability to induce M2 polarization of macrophages and promote angiogenesis, resulting in enhanced osteogenic differentiation in bone marrow mesenchymal stem cells (BMSCs) and thus enhancing bone regeneration. This engineered probiotic hydrogel offers a promising strategy by simultaneously combating bacterial infection and enhancing osteogenic differentiation for chronic osteomyelitis.

Bibliometric and visualized analysis of the applications of exosomes for bone regeneration

Background

Bone defect, a common orthopedic condition, is characterized by a lengthy and impactful treatment period, posing a considerable challenge in clinical settings. Medical technology has advanced notably, and has effectively treated an increasing number of patients with bone defects. Consequently, there has been an explosion of research articles on bone regeneration, including a substantial number on the application of exosomes. Exosomes, especially those derived from stem cells, have been confirmed to be effective in bone regeneration and have garnered widespread attention in the last decade. Therefore, this study conducted a bibliometric analysis on publications related to the application of exosomes for bone regeneration. The objectives are to explore the development history and research hotspots in this field over the past 10 years, predict future development trends, and provide guidance for subsequent research.

Methods

The Web of Science Core Collection (WoSCC) database was searched for articles related to exosomes and bone regeneration published from 1 January 2014, to 31 December 2023. The collected literature was analyzed using software such as Microsoft Excel, CiteSpace 6.3R1, VOSviewer 1.6.20, and the bibliometric online platform (https://bibliometric.com).

Results

A total of 3,004 articles published by 2,729 institutions from 68 countries were included in this study. The number of articles on the application of exosomes for bone regeneration has increased annually over the last decade. China was the most prolific country in this field, with a total of 1,468 papers; Shanghai Jiao Tong University (China) was the institution with the highest number of publications (117 publications). In terms of authors, Xin Wang, Yi Zhang, and Yang Wang were the three who published the highest number of papers, with 14 papers each. Co-citation analysis revealed that the article published by Valadi H in 2007 has the highest number of co-citations (270 times of quotation). Additionally, most research hotspots focused on the function of exosomes and the mechanism of action. Furthermore, the importance of osteoblast differentiation and angiogenesis in bone regeneration has also garnered significant attention from scholars in this field.

Conclusion

This study reviewed the research achievements on the application of exosomes for bone regeneration over the past 10 years, utilizing bibliometric analysis tools. It visualized the countries, institutions, authors, and journals that have made significant contributions to this field, revealed current research hotspots, and finally explored future development trends.

Molecules-mediated bidirectional interactions between microbes and human cells

Complex molecules-mediated interactions, which are based on the bidirectional information exchange between microbes and human cells, enable the defense against diseases and health maintenance. Recently, diverse single-direction interactions based on active metabolites, immunity factors, and quorum sensing signals have largely been summarized separately. In this review, according to a simplified timeline, we proposed the framework of Molecules-mediated Bidirectional Interactions (MBI) between microbe and humans to decipher and understand their intricate interactions systematically. About the microbe-derived interactions, we summarized various molecules, such as short-chain fatty acids, bile acids, tryptophan catabolites, and quorum sensing molecules, and their corresponding human receptors. Concerning the human-derived interactions, we reviewed the effect of human molecules, including hormones, cytokines, and other circulatory metabolites on microbial characteristics and phenotypes. Finally, we discussed the challenges and trends for developing and deciphering molecule-mediated bidirectional interactions and their potential applications in the guard of human health.

Macro/Microgel-Encapsulated, Biofilm-Armored Living Probiotic Platform for Regenerating Bacteria-Infected Diabetic Wounds

Infectious diabetic wounds pose an arduous threat to contemporary healthcare. The combination of refractory biofilms, persistent inflammation, and retarded angiogenesis can procure non-unions and life-threatening complications, calling for advanced therapeutics potent to orchestrate anti-infective effectiveness, benign biocompatibility, pro-reparative immunomodulation, and angiogenic regeneration. Herein, embracing the emergent "living bacterial therapy" paradigm, a designer probiotic-in-hydrogel wound dressing platform is demonstrated. The platform is constructed employing a "macrogel/microgel/biofilm" hierarchical encapsulation strategy, with Lactobacillus casei as the model probiotic. Alginate gels, in both macro and micro forms, along with self-produced probiotic biofilms, served as encapsulating agents. Specifically, live probiotics are enclosed within alginate microspheres, embedded into an alginate bulk matrix, and cultivated to facilitate biofilm self-encasing. This multiscale confinement protected the probiotics and averted their inadvertent escape, while enabling sustained secretion, proper reservation, and localized delivery of therapeutically active probiotic metabolites, such as lactic acid. The resulting biosystem, as validated in vitro/ovo/vivo, elicited well-balanced antibacterial activities and biological compatibility, alongside prominent pro-healing, vasculogenic and anti-inflammatory potencies, thus accelerating the regeneration of infected full-thickness excisional wounds in diabetic mice. Such multiple encapsulation-engineered "all-in-one" probiotic delivery tactic may shed new light on the safe and efficient adoption of live bacteria for treating chronic infectious diseases.

Synthetic nanointerfacial bioengineering of Ti implants: on-demand regulation of implant-bone interactions for enhancing osseointegration

Titanium and its alloys are the most commonly used biometals for developing orthopedic implants to treat various forms of bone fractures and defects, but their clinical performance is still challenged by the unfavorable mechanical and biological interactions at the implant-tissue interface, which substantially impede bone healing at the defects and reduce the quality of regenerated bones. Moreover, the impaired osteogenesis capacity of patients under certain pathological conditions such as diabetes and osteoporosis may further impair the osseointegration of Ti-based implants and increase the risk of treatment failure. To address these issues, various modification strategies have been developed to regulate the implant-bone interactions for improving bone growth and remodeling in situ. In this review, we provide a comprehensive analysis on the state-of-the-art synthetic nanointerfacial bioengineering strategies for designing Ti-based biofunctional orthopedic implants, with special emphasis on the contributions to (1) promotion of new bone formation and binding at the implant-bone interface, (2) bacterial elimination for preventing peri-implant infection and (3) overcoming osseointegration resistance induced by degenerative bone diseases. Furthermore, a perspective is included to discuss the challenges and potential opportunities for the interfacial engineering of Ti implants in a translational perspective. Overall, it is envisioned that the insights in this review may guide future research in the area of biometallic orthopedic implants for improving bone repair with enhanced efficacy and safety.

Probiotic biofilm modified scaffolds for facilitating osteomyelitis treatment through sustained release of bacteriophage and regulated macrophage polarization

Osteomyelitis has gradually become a catastrophic complication in orthopedic surgery due to the formation of bacterial biofilms on the implant surface and surrounding tissue. The therapeutic challenges of antibiotic resistance and poor postoperative osseointegration provide inspiration for the development of bioactive implants. We have strategically designed bioceramic scaffolds modified with Lactobacillus reuteri (LR) and bacteriophages (phages) to achieve both antibacterial and osteogenic effects. Leveraging the tendency of bacteria to adhere to the surface of implants, bioceramics have been modified with LR biofilm to promote bone repair. The LR biofilm, sterilized by pasteurization, prevents sepsis caused by live bacteria and is biocompatible with phages. Phages, being natural enemies of bacteria, not only effectively kill bacteria and inhibit biofilm formation but also readily adsorb onto the surface of bioceramics. Hence, this scaffold, loaded with a phage cocktail, lysates specific bacterial populations, namely Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). More importantly, the inactivated LR biofilm stimulates macrophages RAW264.7 to polarize towards an anti-inflammatory M2 phenotype, creating an immune microenvironment favorable for inducing osteogenic differentiation of rat mesenchymal stem cells in vitro. In a rat model of infectious cranial defects, the scaffold not only effectively eliminated S. aureus and alleviated associated inflammation but also mediated macrophage-mediated immunoregulation, thus resulting in effective osteogenesis. Collectively, these multifunctional modified scaffolds offer an integrated approach to both bacterium elimination and bone repair, presenting a new strategy for bioactive implants in the clinical management of osteomyelitis.

Osseointegration-Related Exosomes for Surface Functionalization of Titanium Implants

Despite that the clinical application of titanium-based implants has achieved great success, patients' own diseases and/or unhealthy lifestyle habits often lead to implant failure. Many studies have been carried out to modify titanium implants to promote osseointegration and implant success. Recent studies showed that exosomes, proactively secreted extracellular vesicles by mammalian cells, could selectively target and modulate the functions of recipient cells such as macrophages, nerve cells, endothelial cells, and bone marrow mesenchymal stem cells that are closely involved in implant osseointegration. Accordingly, using exosomes to functionalize titanium implants has been deemed as a novel and effective way to improve their osseointegration ability. Herein, recent advances pertaining to surface functionalization of titanium implants with exosomes are analyzed and discussed, with focus on the role of exosomes in regulating the functions of osseointegration-related cells, and their immobilization strategies as well as resultant impact on osseointegration ability.

Amino Acid Functionalized SrTiO3 Nanoarrays with Enhanced Osseointegration Through Programmed Rapid Biofilm Elimination and Angiogenesis Controlled by NIR-Driven Gas Therapy

Bacterial biofilm formation is closely associated with persistent infections of medical implants, which can lead to implantation failure. Additionally, the reconstruction of the vascular network is crucial for achieving efficient osseointegration. Herein, an anti-biofilm nanoplatform based on L-arginine (LA)/new indocyanine green (NICG) that is anchored to strontim titanium oxide (SrTiO3) nano-arrays on a titanium (Ti) substrate by introducing polydopamine (PDA) serving as the interlayer is designed and successfully fabricated. Near-infrared light (NIR) is used to excite NICG, generating reactive oxygen species (ROS) that react with LA to release nitric oxide (NO) molecules. Utilizing the concentration-dependent effect of NO, high power density NIR irradiation applied during the early stage after implantation to release a high concentration of NO, which synergized with the photothermal effect of PDA to eliminate bacterial biofilm. Subsequently, the irradiation power density can be finely down-regulated to reduce the NO concentration in subsequent treatment for accelerating the reconstruction of blood vessels. Meanwhile, SrTiO3 nano-arrays improve the hydrophilicity of the implant surface and slowly release strontium (Sr) ions for continuously optimizing the osteogenic microenvironment. Effective biofilm elimination and revascularization alongside the continuous optimization of the osteogenic microenvironment can significantly enhance the osseointegration of the functionalized Ti implant in in vivo animal experiments.

Assessment of Biofilm Formation and Anti-Inflammatory Response of a Probiotic Blend in a Cultured Canine Cell Model

Gut dysbiosis and an inflamed bowel are growing concerns in mammals, including dogs. Probiotic supplements have been used to restore the natural microbial community and improve gastrointestinal health. Biofilm formation, antimicrobial activities, and immunological responses of probiotics are crucial to improving gut health. Thus, we tested a commercial probiotic blend (LabMAX-3), a canine kibble additive comprising Lactobacillus acidophilus, Lacticaseibacillus casei, and Enterococcus faecium for their ability to inactivate common enteric pathogens; their ability to form biofilms; epithelial cell adhesion; and their anti-inflammatory response in the Madin-Darby Canine Kidney (MDCK) cell line. Probiotic LabMAX-3 blend or individual isolates showed a strong inhibitory effect against Salmonella enterica, Listeria monocytogenes, enterotoxigenic Escherichia coli, and Campylobacter jejuni. LabMAX-3 formed biofilms comparable to Staphylococcus aureus. LabMAX-3 adhesion to the MDCK cell line (with or without lipopolysaccharide (LPS) pretreatment) showed comparable adhesion and biofilm formation (p < 0.05) to L. casei ATCC 334 used as a control. LabMAX-3 had no cytotoxic effects on the MDCK cell line during 1 h exposure. The interleukin-10 (IL-10) and tumor necrosis factor alpha (TNFα) ratio of LabMAX-3, compared to the L. casei control, showed a significant increase (p < 0.05), indicating a more pronounced anti-inflammatory response. The data show that LabMAX-3, a canine kibble supplement, can improve gastrointestinal health.

Coaxial electrospun nanofiber accelerates infected wound healing via engineered probiotic biofilm

Bacterial infection is the primary cause of delayed wound healing. Infected wounds suffer from a series of harmful factors in the harsh wound microenvironment (WME), greatly damaging their potential for tissue regeneration. Herein, a novel probiotic biofilm-based antibacterial strategy is proposed through experimentation. Firstly, a series of coaxial polycaprolactone (PCL) / silk fibroin (SF) nanofiber films (termed as PSN-n, n = 0.5, 1.0, 1.5, and 2.0, respectively) are prepared by coaxial electrospinning and their physiochemical properties are comprehensively characterized. Afterward, the PSN-1.5 is selected and co-cultured with L. paracasei to allow the formation of probiotic biofilm. The probiotic biofilm-loaded PSN-1.5 nanofiber film (termed as PSNL-1.5) exhibits relatively good broad-spectrum antibacterial activity, biocompatibility, and enhanced pro-regenerative capability by immunoregulation of M2 macrophage. A wound healing assay is performed using an S. aureus-infected skin defect model. The application effect of PSNL-1.5 is significantly better than that of a commercial nano‑silver burn & scald dressing (Anson®), revealing huge potential for clinical translation. This study is of significant novelty in demonstrating the antibacterial and pro-regenerative abilities of probiotic biofilms. The product of this study will be extensively used for treating infected wounds or other wounds.

Ultrasound-Activated Probiotics Vesicles Coating for Titanium Implant Infections Through Bacterial Cuproptosis-Like Death and Immunoregulation

Implant-associated infections (IAIs) are the main cause of prosthetic implant failure. Bacterial biofilms prevent antibiotic penetration, and the unique metabolic conditions in hypoxic biofilm microenvironment may limit the efficacy of conventional antibiotic treatment. Escaping survival bacteria may not be continually eradicated, resulting in the recurrence of IAIs. Herein, a sonosensitive metal-organic framework of Cu-TCPP (tetrakis(4-carboxyphenyl) porphyrin) nanosheets and tinidazole doped probiotic-derived membrane vesicles (OMVs) with high-penetration sonodynamic therapy (SDT), bacterial metabolic state interference, and bacterial cuproptosis-like death to eradicate IAIs is proposed. The Cu-TCPP can convert O2 to toxic 1O2 through SDT in the normoxic conditions, enhancing the hypoxic microenvironment and activating the antibacterial activity of tinidazole. The released Cu(II) under ultrasound can be converted to Cu(I) by exogenous poly(tannic acid) (pTA) and endogenous glutathione. The disruption of the bacterial membrane by SDT can enhance the Cu(I) transporter activity. Transcriptomics indicate that the SDT-enhanced Cu(I) overload and hypoxia-activated therapy hinder the tricarboxylic acid cycle (TCA), leading to bacterial cuproptosis-like death. Moreover, the OMVs-activated therapy can polarize macrophages to a M2-like phenotype and facilitate bone repair. The sonodynamic biofilm microenvironment modulation strategy, whereby the hypoxia-enhanced microenvironment is potentiated to synergize SDT with OMVs-activated therapy, provides an effective strategy for antibacterial and osteogenesis performance.

Modulations of the skin microbiome in skin disorders: A narrative review from a wound care perspective

The cutaneous microbiome represents a highly dynamic community of bacteria, fungi and viruses. Scientific evidence, particularly from the last two decades, has revealed that these organisms are far from being inconsequential microscopic hitchhikers on the human body, nor are they all opportunistic pathogens waiting for the chance to penetrate the skin barrier and cause infection. In this review, we will describe how dermatological diseases have been found to be associated with disruptions and imbalances in the skin microbiome and how this new evidence had shaped the diagnosis and clinical practice relating to these disorders. We will identify the microbial agents which have been found to directly exacerbate skin diseases, as well as those which can ameliorate many of the symptoms associated with dermatological disorders. Furthermore, we will discuss the studies which suggest that bacteriotherapy, either by topical use of probiotics or by bacteria-derived compounds, can rectify skin microbial imbalances, thereby offering a promising alternative to antibiotic treatment and reducing the risks of antibiotic resistance.

Thermal control of photothermal implants inspired by polar bear skin for the treatment of infected bone defects

Photothermal therapy (PTT) encounters challenges in addressing deep tissue infections, characterized by limited penetration or potential hyperthermal damage to surrounding tissues, initiating undesirable inflammatory cascades. Inspired by polar bear thermal regulation, we present a "bio-based endogenic thermal-adaptive booster" implant coating. This coating integrates a photothermal poly(tannic acid) (pTA) layer, mimicking the "polar bear dark skin", securely linked with anti-inflammatory dexamethasone (Dex), resembling the "secretion", and a red blood cell membrane (RBCM) layer, forming the insulating "transparent fur". The RBCM "fur" demonstrates unexpectedly superior local heat storage, amplifying the photothermal effect of the pTA "skin" by 1.30 times and boosting localized photothermal antibacterial efficiency by 1.30-fold (approximately 99%) compared to those without RBCM. Furthermore, RBCM sustains Dex release and offers additional protection against thermal inflammation, releasing Dex 1.90 times more under NIR irradiation than under non-photothermal conditions. In a rat infectious bone model, the photothermal-boosting implant coating provides a favorable biological interface and achieves a 99.97% photothermal antibacterial ratio, enhancing osseointegration without evident tissue harm, evidenced by a 2.47-fold increase in bone volume fraction and a 2.24-fold reduction in pro-inflammatory cytokines compared to those lacking a RBCM. Insights derived from cell membrane-based thermal-adaptive coatings herald a paradigm shift in efficient and safe PTT.

Effects of inactivated Lactobacillus rhamnosus on growth performance, serum indicators, and colonic microbiota and metabolism of weaned piglets

BACKGROUND

To assess the effects of inactivated Lactobacillus rhamnosus (ILR) on growth performance, serum biochemical indices, colonic microbiota, and metabolomics in weaned piglets, 120 piglets were randomly divided into five groups. Samples in the control group were fed a basal diet, while the experimental ILR1, ILR2, ILR3, and ILR4 groups were fed basal diets supplemented with 0.1%, 0.2%, 0.3%, and 0.4% ILR, respectively. The prefeeding period lasted for 5 days and was followed by a formal period of 28 days.

RESULTS

Compared to the control, the average daily gain increased by 4.38%, 7.98%, 19.32%, and 18.80% for ILR1, ILR2, ILR3, and ILR4, respectively, and the ratio of feed to gain decreased by 0.63%, 3.80%, 12.66%, and 10.76%, respectively. Serum IgA, IgG, IgM, total antioxidant capacity, and glutathione peroxidase levels increased significantly in weaned piglets in the treatment groups. Addition of 0.3% ILR significantly increased the Shannon and Simpson indices of the colonic microbiota in weaned piglets and altered the microbiota composition. Changes in metabolic profiles were observed and were primarily related to the urea cycle, amino acid metabolism, and lipid metabolism.

CONCLUSION

ILR improved growth performance and serum immunological and biochemical indices and optimized the colonic microbiota structure and metabolism of weaned piglets.

Smart responsive staple for dynamic promotion of anastomotic stoma healing

The precise combination of conflicting biological properties through sophisticated structural and functional design to meet all the requirements of anastomotic healing is of great demand but remains challenging. Here, we develop a smart responsive anastomotic staple (Ti-OH-MC) by integrating porous titanium anastomotic staple with multifunctional polytannic acid/tannic acid coating. This design achieves dynamic sequential regulation of antibacterial, anti-inflammatory, and cell proliferation properties. During the inflammatory phase of the anastomotic stoma, our Ti-OH-MC can release tannic acid to provide antibacterial and anti-inflammatory properties, together with immune microenvironment regulation function. At the same time, as the healing progresses, the multifunctional coating gradually falls off to expose the porous structure of the titanium anastomotic staple, which promotes cell adhesion and proliferation during the later proliferative and remodeling phases. As a result, our Ti-OH-MC exceeds the properties of clinically used titanium anastomotic staple, and can effectively promote the healing. The staple's preparation strategy is simple and biocompatible, promising for industrialisation and clinical application. This work provides an effective anastomotic staple for anastomotic stoma healing and serve as a reference for the functional design and preparation of other types of titanium-based tissue repair materials.

New clues for postbiotics to improve host health: a review from the perspective of function and mechanisms

Strain activity and stability severely limit the beneficial effects of probiotics in modulating host health. Postbiotics have emerged as a promising alternative as they can provide similar or even enhanced efficacy to probiotics, even under inactivated conditions. This review introduces the ingredients, preparation, and identification techniques of postbiotics, focusing on the comparison of the advantages and limitations between probiotics and postbiotics based on their mechanisms and applications. Inactivation treatment is the most significant difference between postbiotics and probiotics. We highlight the use of emerging technologies to inactivate probiotics, optimize process conditions to maintain the activity of postbiotics, or scale up their production. Postbiotics have high stability which can overcome unfavorable factors, such as easy inactivation and difficult colonization of probiotics after entering the intestine, and are rapidly activated, allowing continuous and rapid optimization of the intestinal microecological environment. They provide unique mechanisms, and multiple targets act on the gut-organ axis, co-providing new clues for the study of the biological functions of postbiotics. We summarize the mechanisms of action of inactivated lactic acid bacteria, highlighting that the NF-κB and MAPK pathways can be used as immune targeting pathways for postbiotic modulation of host health. Generally, we believe that as the classification, composition, and efficacy mechanism of postbiotics become clearer they will be more widely used in food, medicine, and other fields, greatly enriching the dimensions of food innovation. © 2024 Society of Chemical Industry.

Artificial Phages with Biocatalytic Spikes for Synergistically Eradicating Antibiotic-Resistant Biofilms

Antibiotic-resistant pathogens have become a global public health crisis, especially biofilm-induced refractory infections. Efficient, safe, and biofilm microenvironment (BME)-adaptive therapeutic strategies are urgently demanded to combat antibiotic-resistant biofilms. Here, inspired by the fascinating biological structures and functions of phages, the de novo design of a spiky Ir@Co3O4 particle is proposed to serve as an artificial phage for synergistically eradicating antibiotic-resistant Staphylococcus aureus biofilms. Benefiting from the abundant nanospikes and highly active Ir sites, the synthesized artificial phage can simultaneously achieve efficient biofilm accumulation, extracellular polymeric substance (EPS) penetration, and superior BME-adaptive reactive oxygen species (ROS) generation, thus facilitating the in situ ROS delivery and enhancing the biofilm eradication. Moreover, metabolomics found that the artificial phage obstructs the bacterial attachment to EPS, disrupts the maintenance of the BME, and fosters the dispersion and eradication of biofilms by down-regulating the associated genes for the biosynthesis and preservation of both intra- and extracellular environments. The in vivo results demonstrate that the artificial phage can treat the biofilm-induced recalcitrant infected wounds equivalent to vancomycin. It is suggested that the design of this spiky artificial phage with synergistic "penetrate and eradicate" capability to treat antibiotic-resistant biofilms offers a new pathway for bionic and nonantibiotic disinfection.

Novel Palladium Hydride Surface Enabling Simultaneous Bacterial Killing and Osteogenic Formation through Proton Capturing and Activation of Antioxidant System in Immune Microenvironments

Achieving bacterial killing and osteogenic formation on an implant surface rarely occurs. In this study, a novel surface design-a palladium hydride (PdHx) film that enables these two distinct features to coexist is introduced. The PdHx lattice captures protons in the extracellular microenvironment of bacteria, disrupting their normal metabolic activities, such as ATP synthesis, nutrient co-transport, and oxidative stress. This disruption leads to significant bacterial death, as evidenced by RNA sequence analysis. Additionally, the unique enzymatic activity and hydrogen-loading properties of PdHx activate the human antioxidant system, resulting in the rapid clearance of reactive oxygen species. This process reshapes the osteogenic immune microenvironment, promoting accelerated osteogenesis. These findings reveal that the downregulation of the NOD-like receptor signaling pathway is critical for activating immune cells toward M2 phenotype polarization. This novel surface design provides new strategies for modifying implant coatings to simultaneously prevent bacterial infection, reduce inflammation, and enhance tissue regeneration, making it a noteworthy contribution to the field of advanced materials.

Dress me an outfit: advanced probiotics hybrid systems for intelligent IBD therapy

Inflammation bowel disease (IBD) has emerged as a public health challenge worldwide; with high incidence and rapid prevalence, it has troubled billions of people and further induced multitudinous systemic complications. Recent decade has witnessed the vigorous application of food-borne probiotics for IBD therapy; however, the complicated and changeable environments of digestive tract have forced probiotics to face multiple in vivo pressures, consequently causing unsatisfied prophylactic or therapeutic efficacy attributed to off-targeted arrival, damaged viability, insufficient colonization efficiency, etc. Fortunately, arisen hybrid technology has provided versatile breakthroughs for the targeted transplantation of probiotics. By ingeniously modifying probiotics to form probiotics hybrid systems (PHS), the biological behaviors of probiotics in vivo could be mediated, the interactions between probiotics with intestinal components can be facilitated, and diverse advanced probiotic-based therapies for IBD challenge can be developed, which attribute to the intelligent response to microenvironment of PHS, and intelligent design of PHS for multiple functions combination. In this review, various PHS were categorized and their intestinal behaviors were elucidated systematically, their therapeutic effects and intrinsic mechanism were further analyzed. Besides, shortages of present PHS and the corresponding solutions have been discussed, based on which the future perspectives of this field have also been proposed. The undeniable fact is that PHS show an incomparable future to bring the next generation of advanced food science.

The Effect of Antibacterial-Osteogenic Surface Modification on the Osseointegration of Titanium Implants: A Static and Dynamic Strategy

Titanium (Ti) and its alloys are widely used biomaterials in bone repair. Although these biomaterials possess stable properties and good biocompatibility, the high elastic modulus and low surface activity of Ti implants have often been associated with infection, inflammation, and poor osteogenesis. Therefore, there is an urgent need to modify the surface of Ti implants, where changes in surface morphology or coatings loading can confer specific functions to help them adapt to the osseointegration formation phase and resist bacterial infection. This can further ensure a healthy microenvironment for bone regeneration as well as the promotion of immunomodulation, angiogenesis, and osteogenesis. Therefore, in this review, we evaluated various functional Ti implants after surface modification, both in terms of static modifications and dynamic response strategies, mainly focusing on the synergistic effects of antimicrobial activities and functionalized osteogenic. Finally, the current challenges and future perspectives are summarized to provide innovative and effective solutions for osseointegration and bone defect repair.

Engineering bacterial warriors: harnessing microbes to modulate animal physiology

A central goal of synthetic biology is the reprogramming of living systems for predetermined biological functions. While many engineering efforts have been made in living systems, these innovations have been mainly employed with microorganisms or cell lines. The engineering of multicellular organisms including animals remains challenging owing to the complexity of these systems. In this context, microbes, with their intricate impact on animals, have opened new opportunities. Through the utilization of the symbiotic relationships between microbes and animals, researchers have effectively manipulated animals in various ways using engineered microbes. This focused approach has demonstrated its significance in scientific exploration and engineering with model animals, coral preservation and restoration, and advancements in human health.

Activating Angiogenesis and Immunoregulation to Propel Bone Regeneration via Deferoxamine-Laden Mg-Mediated Tantalum Oxide Nanoplatform

Vascularization and inflammation management are essential for successful bone regeneration during the healing process of large bone defects assisted by artificial implants/fillers. Therefore, this study is devoted to the optimization of the osteogenic microenvironment for accelerated bone healing through rapid neovascularization and appropriate inflammation inhibition that were achieved by applying a tantalum oxide (TaO)-based nanoplatform carrying functional substances at the bone defect. Specifically, TaO mesoporous nanospheres were first constructed and then modified by functionalized metal ions (Mg2+) with the following deferoxamine (DFO) loading to obtain the final product simplified as DFO-Mg-TaO. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed that the product was homogeneously dispersed hollow nanospheres with large specific surface areas and mesoporous shells suitable for loading Mg2+ and DFO. The biological assessments indicated that DFO-Mg-TaO could enhance the adhesion, proliferation, and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs). The DFO released from DFO-Mg-TaO promoted angiogenetic activity by upregulating the expressions of hypoxia-inducible factor-1 (HIF-1α) and vascular endothelial growth factor (VEGF). Notably, DFO-Mg-TaO also displayed anti-inflammatory activity by reducing the expressions of pro-inflammatory factors, benefiting from the release of bioactive Mg2+. In vivo experiments demonstrated that DFO-Mg-TaO integrated with vascular regenerative, anti-inflammatory, and osteogenic activities significantly accelerated the reconstruction of bone defects. Our findings suggest that the optimized DFO-Mg-TaO nanospheres are promising as multifunctional fillers to speed up the bone healing process.

A self-activating electron transfer antibacterial strategy: Co3O4/TiO2 P-N heterojunctions combined with photothermal therapy

Implant-associated infections are significant impediments to successful surgical outcomes, often resulting from persistent bacterial contamination. It has been hypothesized that bacteria can transfer electrons to semiconductors with comparable potential to the biological redox potential (BRP). Building on this concept, we developed an antibiotic-free bactericidal system, Co3O4/TiO2-Ti, capable of achieving real-time and sustainable bactericidal effects. Our study demonstrated that Co3O4/TiO2-Ti, possessing an appropriately set valence band, initiated charge transfer, reactive oxygen species (ROS) production, and membrane damage in adherent Staphylococcus aureus (S. aureus). Notably, in vivo experiments illustrated the remarkable antibacterial activity of Co3O4/TiO2-Ti, while promoting soft-tissue reconstruction and demonstrating excellent cytocompatibility. Transcriptomic analysis further revealed a down-regulation of aerobic respiration-associated genes and an up-regulation of ROS-associated genes in S. aureus in the presence of Co3O4/TiO2-Ti compared to Ti. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis and gene set enrichment analysis (GSEA) identified alterations in respiratory metabolism, oxidative phosphorylation, and the synthesis of amino acid in S. aureus cultured on Co3O4/TiO2-Ti. Furthermore, when combined with near-infrared (NIR) irradiation and photothermal therapy (PTT), Co3O4/TiO2-Ti eliminated 95.71% of floating and adherent S. aureus in vitro. The findings suggest that this antibiotic-free strategy holds substantial promise in enhancing implant sterilization capabilities, thereby contributing to the prevention and treatment of bacterial infections through bandgap engineering of implants and NIR irradiation.

Tricarboxylic Acid Cycle Metabolite-Coordinated Biohydrogels Augment Cranial Bone Regeneration Through Neutrophil-Stimulated Mesenchymal Stem Cell Recruitment and Histone Acetylation-Mediated Osteogenesis

Cranial bone defects remain a major clinical challenge, increasing patients' life burdens. Tricarboxylic acid (TCA) cycle metabolites play crucial roles in facilitating bone tissue regeneration. However, the development of TCA cycle metabolite-modified biomimetic grafts for skull bone regeneration still needs to be improved. The mechanism underlying the release of TCA cycle metabolites from biomaterials in regulating immune responses and mesenchymal stem cell (MSC) fate (migration and differentiation) remains unknown. Herein, this work constructs biomimetic hydrogels composed of gelatin and chitosan networks covalently cross-linked by genipin (CGG hydrogels). A series of TCA cycle metabolite-coordinated CGG hydrogels with strong mechanical and antiswelling performances are subsequently developed. Remarkably, the citrate (Na3Cit, Cit)-coordinated CGG hydrogels (CGG-Cit hydrogels) with the highest mechanical modulus and strength significantly promote skull bone regeneration in rat and murine cranial defects. Mechanistically, using a transgenic mouse model, bulk RNA sequencing, and single-cell RNA sequencing, this work demonstrates that CGG-Cit hydrogels promote Gli1+ MSC migration via neutrophil-secreted oncostatin M. Results also indicate that citrate improves osteogenesis via enhanced histone H3K9 acetylation on osteogenic master genes. Taken together, the immune microenvironment- and MSC fate-regulated CGG-Cit hydrogels represent a highly efficient and facile approach toward skull bone tissue regeneration with great potential for bench-to-bedside translation.

Injectable Living Probiotic Dressing Built by Droplet-Based Microfluidics and Photo-Cross-Linking to Prevent Pathogenic Infection and Promote Wound Repair

The treatment of infected wounds faces great challenges due to the emergence of antibiotic resistance and the lack of persistence in drug release. Here, a living probiotic dressing is constructed by integrating droplet-shearing and photo-cross-linking. Saccharomyces boulardii (S. boulardii), the only probiotic used clinically, is encapsulated and attached to a wound under light irradiation. A double-layer hydrogel provides a protective barrier for cell growth and proliferation while preventing the escape of S. boulardii. The living probiotic dressing shows superior biosafety with fibroblast cells. Strikingly, in vitro and in vivo experiments indicate that the living probiotic dressing not only inhibits bacterial survival and colonization, but also alleviates inflammation and accelerates wound closure. More significantly, the living probiotic dressing promotes collagen deposition and neovascularization, which accelerates wound healing. This work can provide new ideas for clinical wound treatment and widen the application of probiotics in tissue engineering.

Instant Protection Spray for Anti-Infection and Accelerated Healing of Empyrosis

Distinct from common injuries, deep burns often require a chronic recovery cycle for healing and long-term antibiotic treatment to prevent infection. The rise of drug-resistant bacteria has caused antibiotics to no longer be perfect, and continuous drug use can easily lead to repeated infection and even death. Inspired by wild animals that chew plants to prevent wound infection, probiotic extracts with a structure similar to the tailspike of phage are obtained from Lactobacillus casei and combined with different flavones to design a series of nonantibiotic bactericides. These novel antibacterial agents are combined with a rapid gelation spray with a novel cross-angle layout to form an instant protection spray (IPS) and provide a physical and anti-infectious barrier for burns within 30 s. This IPS is able to sterilize 100.00% and 96.14% of multidrug-resistant Staphylococcus aureus (MRSA) in vitro and in vivo, respectively. In addition, it is found to effectively reduce inflammation in MRSA-infected burns in rats and to promote tissue healing.

Sustainable Sources of Raw Materials for Additive Manufacturing of Bone-Substituting Biomaterials

The need for sustainable development has never been more urgent, as the world continues to struggle with environmental challenges, such as climate change, pollution, and dwindling natural resources. The use of renewable and recycled waste materials as a source of raw materials for biomaterials and tissue engineering is a promising avenue for sustainable development. Although tissue engineering has rapidly developed, the challenges associated with fulfilling the increasing demand for bone substitutes and implants remain unresolved, particularly as the global population ages. This review provides an overview of waste materials, such as eggshells, seashells, fish residues, and agricultural biomass, that can be transformed into biomaterials for bone tissue engineering. While the development of recycled metals is in its early stages, the use of probiotics and renewable polymers to improve the biofunctionalities of bone implants is highlighted. Despite the advances of additive manufacturing (AM), studies on AM waste-derived bone-substitutes are limited. It is foreseeable that AM technologies can provide a more sustainable alternative to manufacturing biomaterials and implants. The preliminary results of eggshell and seashell-derived calcium phosphate and rice husk ash-derived silica can likely pave the way for more advanced applications of AM waste-derived biomaterials for sustainably addressing several unmet clinical applications.

2D silicene nanosheets-loaded coating for combating implant-associated infection

Implant-associated infection (IAI) is an unsolved problem in orthopaedics. Current therapies, including antibiotics and surgical debridement, can lead severe clinical and financial burdens on patients. Therefore, there is an urgent need to reinforce the inherent antibacterial properties of implants. Recently, two-dimensional (2D) silicene nanosheets (SNs) have gained increasing attention in biomedical fields owing to their considerable biocompatibility, biodegradability and strong photothermal-conversion performance. Herein, a dual-functional photosensitive coating on a Ti substrate (denoted as TPSNs) was rationally fabricated for bacterial inhibition and osteogenesis promotion. For the first time, SNs were loaded onto the surface of implants. Hyperthermia generated by the SNs and polydopamine (PDA) coating under 808 nm laser irradiation achieved the in vitro anti-bacterial efficiency of 90.7 ± 2.4 % for S. aureus and 88.0 ± 5.8 % for E. coli, respectively. In addition, TPSNs exhibited promising biocompatibility for the promotion of BMSC (bone marrow mesenchymal stem cells) proliferation and spreading. The presence of silicon (Si) in TPSNs contributed to the improved osteogenic differentiation of BMSCs, elevating the expressions of RUNX2 and OCN. In animal experiments, the combination of TPSNs with photothermal therapy (PTT) achieved an anti-bacterial efficiency of 89.2 % ± 1.6 % against S. aureus. Furthermore, TPSNs significantly improved bone-implant osseointegration in vivo. Overall, the development of a dual-functional TPSNs coating provides a new strategy for combating IAI.

Mechanism Insights of Antibacterial Surfaces Coated with Dead Probiotics

To understand the antimicrobial effect of surfaces fabricated with dead probiotics, we prepared surfaces decorated with dead probiotics Lactobacillus rhamnosus GG (LGG) with varied inactivation methods and explored their inhibitory interactions with Pseudomonas aeruginosa (PAO1). By combining several techniques, i.e., digital holographic microscopy (DHM), atomic force microscopy (AFM), RNA sequencing, and metabolomic analysis, we studied the three-dimensional (3D) swimming behaviors, surface adhesion, biofilm formation, and adaptive responses of PAO1 near such surfaces. The results show that planktonic PAO1 decreases their flick and reverse motions by downregulating the chemotaxis pathway and accelerates with less accumulation near dead LGG surfaces by upregulating the flagellar assembly pathway and decreasing cyclic adenosine monophosphate. Distinct from live siblings, the surfaces decorated with dead LGG show a significant reduction in adhesion strength with PAO1 and inhibit biofilm formation with more downregulated genes in the Pseudomonas quinolone signal and biofilm formation pathway. We demonstrate that the antibacterial ability of such surfaces stems from the gradually released lysate from the dead LGG that is unfavorable to PAO1 in close proximity. The releasing rate and order depend on the cell membrane integrity, which closely relates to the inactivation methods.

Physicochemical Characterization and Immunomodulatory Activity of Polyelectrolyte Multilayer Coatings Incorporating an Exopolysaccharide from Bifidobacterium longum

Immunoregulatory polysaccharides from probiotic bacteria have potential in biomedical engineering. Here, a negatively charged exopolysaccharide from Bifidobacterium longum with confirmed immunoregulatory activity (EPS624) was applied in multilayered polyelectrolyte coatings with positively charged chitosan. EPS624 and coatings (1, 5, and 10 layers and alginate-substituted) were characterized by the zeta potential, dynamic light scattering, size exclusion chromatography, scanning electron microscopy, and atomic force microscopy. Peripheral blood mononuclear cells (hPBMCs) and fibroblasts were exposed for 1, 3, 7, and 10 days with cytokine secretion, viability, and morphology as observations. The coatings showed an increased rugosity and exponential growth mode with an increasing number of layers. A dose/layer-dependent IL-10 response was observed in hPBMCs, which was greater than EPS624 in solution and was stable over 7 days. Fibroblast culture revealed no toxicity or metabolic change after exposure to EPS624. The EPS624 polyelectrolyte coatings are cytocompatible, have immunoregulatory properties, and may be suitable for applications in biomedical engineering.

Effective Modulation of Inflammation and Oxidative Stress for Enhanced Regeneration of Intervertebral Discs Using 3D Porous Hybrid Protein Nanoscaffold

Degeneration of fibrocartilaginous tissues is often associated with complex pro-inflammatory factors. These include reactive oxygen species (ROS), cell-free nucleic acids (cf-NAs), and epigenetic changes in immune cells. To effectively control this complex inflammatory signaling, it developed an all-in-one nanoscaffold-based 3D porous hybrid protein (3D-PHP) self-therapeutic strategy for treating intervertebral disc (IVD) degeneration. The 3D-PHP nanoscaffold is synthesized by introducing a novel nanomaterial-templated protein assembly (NTPA) strategy. 3D-PHP nanoscaffolds that avoid covalent modification of proteins demonstrate inflammatory stimuli-responsive drug release, disc-mimetic stiffness, and excellent biodegradability. Enzyme-like 2D nanosheets incorporated into nanoscaffolds further enabled robust scavenging of ROS and cf-NAs, reducing inflammation and enhancing the survival of disc cells under inflammatory stress in vitro. Implantation of 3D-PHP nanoscaffolds loaded with bromodomain extraterminal inhibitor (BETi) into a rat nucleotomy disc injury model effectively suppressed inflammation in vivo, thus promoting restoration of the extracellular matrix (ECM). The resulting regeneration of disc tissue facilitated long-term pain reduction. Therefore, self-therapeutic and epigenetic modulator-encapsulated hybrid protein nanoscaffold shows great promise as a novel approach to restore dysregulated inflammatory signaling and treat degenerative fibrocartilaginous diseases, including disc injuries, providing hope and relief to patients worldwide.

Genetically engineered Lactobacillus paracasei rescues colonic angiotensin converting enzyme 2 (ACE2) and attenuates hypertension in female Ace2 knock out rats

Engineered gut microbiota represents a new frontier in medicine, in part serving as a vehicle for the delivery of therapeutic biologics to treat a range of host conditions. The gut microbiota plays a significant role in blood pressure regulation; thus, manipulation of gut microbiota is a promising avenue for hypertension treatment. In this study, we tested the potential of Lactobacillus paracasei, genetically engineered to produce and deliver human angiotensin converting enzyme 2 (Lacto-hACE2), to regulate blood pressure in a rat model of hypertension with genetic ablation of endogenous Ace2 (Ace2-/- and Ace2-/y). Our findings reveal a sex-specific reduction in blood pressure in female (Ace2-/-) but not male (Ace2-/y) rats following colonization with the Lacto-hACE2. This beneficial effect of lowering blood pressure was aligned with a specific reduction in colonic angiotensin II, but not renal angiotensin II, suggesting the importance of colonic Ace2 in the regulation of blood pressure. We conclude that this approach of targeting the colon with engineered bacteria for delivery of ACE2 represents a promising new paradigm in the development of antihypertensive therapeutics.

Novel scaffold platforms for simultaneous induction osteogenesis and angiogenesis in bone tissue engineering: a cutting-edge approach

Despite the recent advances in the development of bone graft substitutes, treatment of critical size bone defects continues to be a significant challenge, especially in the elderly population. A current approach to overcome this challenge involves the creation of bone-mimicking scaffolds that can simultaneously promote osteogenesis and angiogenesis. In this context, incorporating multiple bioactive agents like growth factors, genes, and small molecules into these scaffolds has emerged as a promising strategy. To incorporate such agents, researchers have developed scaffolds incorporating nanoparticles, including nanoparticulate carriers, inorganic nanoparticles, and exosomes. Current paper provides a summary of the latest advancements in using various bioactive agents, drugs, and cells to synergistically promote osteogenesis and angiogenesis in bone-mimetic scaffolds. It also discusses scaffold design properties aimed at maximizing the synergistic effects of osteogenesis and angiogenesis, various innovative fabrication strategies, and ongoing clinical studies.

A 3D Bioprinted Nanoengineered Hydrogel with Photoactivated Drug Delivery for Tumor Apoptosis and Simultaneous Bone Regeneration via Macrophage Immunomodulation

One of the significant challenges in bone tissue engineering (BTE) is the healing of traumatic tissue defects owing to the recruitment of local infection and delayed angiogenesis. Herein, a 3D printable multi-functional hydrogel composing polyphenolic carbon quantum dots (CQDs, 100 µg mL-1 ) and gelatin methacryloyl (GelMA, 12 wt%) is reported for robust angiogenesis, bone regeneration and anti-tumor therapy. The CQDs are synthesized from a plant-inspired bioactive molecule, 1, 3, 5-trihydroxybenzene. The 3D printed GelMA-CQDs hydrogels display typical shear-thinning behavior with excellent printability. The fabricated hydrogel displayed M2 polarization of macrophage (Raw 264.7) cells via enhancing anti-inflammatory genes (e.g., IL-4 and IL10), and induced angiogenesis and osteogenesis of human bone mesenchymal stem cells (hBMSCs). The bioprinted hBMSCs are able to produce vessel-like structures after 14 d of incubation. Furthermore, the 3D printed hydrogel scaffolds also show remarkable near infra-red (NIR) responsive properties under 808 nm NIR light (1.0 W cm-2 ) irradiation with controlled release of antitumor drugs (≈49%) at pH 6.5, and thereby killing the osteosarcoma cells. Therefore, it is anticipated that the tissue regeneration and healing ability with therapeutic potential of the GelMA-CQDs scaffolds may provide a promising alternative for traumatic tissue regeneration via augmenting angiogenesis and accelerated immunomodulation.

The role of probiotics in tissue engineering and regenerative medicine

Tissue engineering and regenerative medicine (TERM) as an emerging field is a multidisciplinary science and combines basic sciences such as biomaterials science, biology, genetics and medical sciences to achieve functional TERM-based products to regenerate or replace damaged or diseased tissues or organs. Probiotics are useful microorganisms which have multiple effective functions on human health. They have some immunomodulatory and biocompatibility effects and improve wound healing. In this article, we describe the latest findings on probiotics and their pro-healing properties on various body systems that are useable in regenerative medicine. Therefore, this review presents a new perspective on the therapeutic potential of probiotics for TERM.

The Potential Value of Probiotics after Dental Implant Placement

Dental implantation is currently the optimal solution for tooth loss. However, the health and stability of dental implants have emerged as global public health concerns. Dental implant placement, healing of the surgical site, osseointegration, stability of bone tissues, and prevention of peri-implant diseases are challenges faced in achieving the long-term health and stability of implants. These have been ongoing concerns in the field of oral implantation. Probiotics, as beneficial microorganisms, play a significant role in the body by inhibiting pathogens, promoting bone tissue homeostasis, and facilitating tissue regeneration, modulating immune-inflammatory levels. This review explores the potential of probiotics in addressing post-implantation challenges. We summarize the existing research regarding the importance of probiotics in managing dental implant health and advocate for further research into their potential applications.

Enhancing Microwave Dynamic Effects via Surface States of Ultrasmall 2D MOF Triggered by Interface Confinement for Antibiotics-Free Therapy

Microwave (MV)-trigged dynamic therapy based on MV-responsive materials is promising for treating deep infection diseases that cannot be effectively treated by antibiotics, like life-threatening osteomyelitis. Surface states of materials affect the generation of free charges under the excitation source with energy less than the band gap, consequently influencing the MV dynamic effects. Herein, an MV responsive system with interface confined 2D metal-organic framework (2D MOF) on oxidized carbon nanotube (CNT) is prepared, in which the ultrasmall Cu-based 2D MOF possesses sufficient surface/interface defects, endowing the system a large number of surface states. Under MV irradiation, the synthesized CNT-2D MOF not only efficiently absorbs and converts the microwave into heat for microwaveocaloric therapy (MCT) via enhanced hetero-interfacial polarization, but also generates excited electrons via surface state for microwave dynamic therapy (MDT). This biocompatible CNT-2D MOF exhibits highly effective broad-spectrum antimicrobial activity against seven pathogenic bacteria, including Gram-negative and Gram-positive pathogens, under 7 min MV irradiation. And this system is proven to efficiently eradicate Staphylococcus aureus infected rabbit tibia osteomyelitis. Significantly, MV-excited MCT and MDT of CNT-CuHHTP developed in this study makes a major step forward in antibiotic-free MV therapy in deep tissue bacterial infection diseases.

Bacteria-based multiplex system eradicates recurrent infections with drug-resistant bacteria via photothermal killing and protective immunity elicitation

BACKGROUND

The high mortality associated with drug-resistant bacterial infections is an intractable clinical problem resulting from the low susceptibility of these bacteria to antibiotics and the high incidence of recurrent infections.

METHODS

Herein, a photosynthetic bacteria-based multiplex system (Rp@Al) composed of natural Rhodopseudomonas palustris (Rp) and Food and Drug Administration-approved aluminum (Al) adjuvant, was developed to combat drug-resistant bacterial infections and prevent their recurrence. We examined its photothermal performance and in vitro and in vivo antibacterial ability; revealed its protective immunomodulatory effect; verified its preventative effect on recurrent infections; and demonstrated the system's safety.

RESULTS

Rp@Al exhibits excellent photothermal properties with an effective elimination of methicillin-resistant Staphylococcus aureus (MRSA). In addition, Rp@Al enhances dendritic cell activation and further triggers a T helper 1 (T_H1)/T_H2 immune response, resulting in pathogen-specific immunological memory against recurrent MRSA infection. Upon second infection, Rp@Al-treated mice show significantly lower bacterial burden, faster abscess recovery, and higher survival under near-lethal infection doses than control mice.

CONCLUSIONS

This innovative multiplex system, with superior photothermal and immunomodulatory effects, presents great potential for the treatment and prevention of drug-resistant bacterial infections.

Novel nutrition strategies to enhance recovery after surgery

Surgery and traumatic injury set off a cascade of metabolic changes that are becoming better understood. Recently, strategies and protocols have been developed for optimizing outcomes, and this has yielded beneficial results. This brief review evaluates three specific nutrition or metabolic interventions in the postoperative setting that attempt to optimize outcomes. We limited this to three subspecialty areas including oncologic surgery, orthopedic surgery, and cardiac surgery. These agents included fish oils, factors to prevent dysbiosis, and resistance exercise and its role in enhancing protein update. Where these novel agents fit into the basic tenets of postoperative nutrition interventions does not change the narrative: deliver graduated early enteral feeding to attenuate the metabolic response to surgical stress, maintain the gastrointestinal mucosal barrier, use immune/metabolic modulation to enhance immune response while attenuating excessive inflammation, and support the microbiome.

Development and Evaluation of Novel Encapsulated Isoeugenol-Liposomal Gel Carrier System for Methicillin-Resistant Staphylococcus aureus

In recent years, methicillin-resistant Staphylococcus aureus (MRSA) bacteria have seriously threatened the health and safety of the world’s population. This challenge demands the development of alternative therapies based on plant origin. This molecular docking study ascertained the orientation and intermolecular interactions of isoeugenol within penicillin-binding protein 2a. In this present work, isoeugenol as an anti-MRSA therapy was selected by encapsulating it into a liposomal carrier system. After encapsulation into the liposomal carrier, it was evaluated for encapsulation efficiency (%), particle size, zeta potential, and morphology. The percentage entrapment efficiency (% EE) was observed to be 57.8 ± 2.89% with a particle size of 143.31 ± 7.165 nm, a zeta potential of (−)25 mV, and morphology was found to be spherical and smooth. After this evaluation, it was incorporated into a 0.5% Carbopol gel for a smooth and uniform distribution on the skin. Notably, the isoeugenol-liposomal gel was smooth on the surface with a pH of 6.4, suitable viscosity, and spreadability. Interestingly, the developed isoeugenol-liposomal gel was safe for human use, with more than 80% cell viability. The in vitro drug release study shows promising results with 75.95 ± 3.79% of drug release after 24 h. The minimum inhibitory concentration (MIC) was 8.236 µg/mL. Based on this, it can be concluded that encapsulating isoeugenol into the liposomal gel is a potential carrier for MRSA treatment.

Enzymatic bionanocatalysts for combating peri-implant biofilm infections by specific heat-amplified chemodynamic therapy and innate immunomodulation

Bacterial biofilm-associated infection is a life-threatening emergency contributing from drug resistance and immune escape. Herein, a novel non-antibiotic strategy based on the synergy of bionanocatalysts-driven heat-amplified chemodynamic therapy (CDT) and innate immunomodulation is proposed for specific biofilm elimination by the smart design of a biofilm microenvironment (BME)-responsive double-layered metal-organic framework (MOF) bionanocatalysts (MACG) composed of MIL-100 and CuBTC. Once reaching the acidic BME, the acidity-triggered degradation of CuBTC allows the sequential release of glucose oxidase (GOx) and an activable photothermal agent, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS). GOx converts glucose into H₂O₂ and gluconic acid, which can further acidify the BME to accelerate the CuBTC degradation and GOx/ABTS release. The in vitro and in vivo results show that horseradish peroxidase (HRP)-mimicking MIL-100 in the presence of self-supplied H₂O₂ can catalyze the oxidation of ABTS into oxABTS to yield a photothermal effect that breaks the biofilm structure via eDNA damage. Simultaneously, the Cu ion released from the degraded CuBTC can deplete glutathione and catalyze the splitting of H₂O₂ into •OH, which can effectively penetrate the heat-induced loose biofilms and kill sessile bacteria (up to 98.64%), such as E. coli and MRSA. Particularly, MACG-stimulated M1-macrophage polarization suppresses the biofilm regeneration by secreting pro-inflammatory cytokines (e.g., IL-6, TNF-α, etc.) and forming a continuous pro-inflammatory microenvironment in peri-implant biofilm infection animals for at least 14 days. Such BME-responsive strategy has the promise to precisely eliminate refractory peri-implant biofilm infections with extremely few adverse effects.

ROS Scavenging and inflammation-directed polydopamine nanoparticles regulate gut immunity and flora therapy in inflammatory bowel disease

Dysfunction of the intestinal mucosal immune system and dysbiosis of the intestinal microflora can induce inflammatory bowel disease. However, drug-mediated clinical treatment remains a challenge due to its poor therapeutic efficacy and severe side effects. Herein, a ROS scavenging and inflammation-directed nanomedicine is designed and fabricated by coupling polydopamine nanoparticles with mCRAMP, an antimicrobial peptide, while wrapping macrophage membrane in the outer layer. The designed nanomedicine reduced the secretion of pro-inflammatory cytokines and elevate the expression of anti-inflammatory cytokine in vivo and in vitro inflammation models, demonstrating its significant ability of improving inflammatory responses. Importantly, the macrophage membrane encapsulated nanoparticles exhibit the obviously enhanced targeting performance in local inflamed tissues. Furthermore, the 16S rRNA sequencing of fecal microorganisms showed that probiotics increased and pathogenic bacteria were inhibited after oral delivery the nanomedicine, indicating that the designed nano platform played a significant role in optimizing intestinal microbiome. Taken together, the designed nanomedicine are not only easy to prepare and exhibit high biocompatibility, but also show the inflammatory targeting property, anti-inflammatory function and positive regulation of intestinal flora, thus providing a new idea for the intervention and treatment of colitis. STATEMENT OF SIGNIFICANCE: Inflammatory bowel disease (IBD), a chronic and intractable disease, may lead to colon cancer in severe cases without effective treatment. However, clinical drugs are largely ineffective owing to insufficient therapeutic efficacies and side effects. Herein, we constructed a biomimetic polydopamine nanoparticle for oral administration to treat the IBD by modulating mucosal immune homeostasis and optimizing intestinal microorganisms. In vitro and in vivo experiments showed that the designed nanomedicine not only exhibits the anti-inflammatory function and inflammatory targeting property but also positively regulate the gut microflora. Taken together, the designed nanomedicine combined immunoregulation and intestinal microecology modulation to significantly enhance the therapeutic effect on colitis in mice, thus providing a new approach for the clinical treatment of colitis.

Probiotic-Functionalized Silk Fibroin/Sodium Alginate Scaffolds with Endoplasmic Reticulum Stress-Relieving Properties for Promoted Scarless Wound Healing

Bioactive substances such as probiotics are becoming a research hotspot in the field of tissue regeneration due to their excellent regulatory functions. Here, we proposed to load Lactobacillus casei onto a bilayer silk fibroin/sodium alginate (SF/SA) scaffold to endow the scaffold with both antibacterial and regenerative properties. The performance of the scaffold was characterized systemically. The L. casei-loaded scaffolds (L-SF/SA) bring in lactic acid, which has antibacterial and wound healing properties. In vitro, the cell-free supernatant (CFS) of L. casei inhibited the transformation of fibroblasts to myofibroblasts and relieved the endoplasmic reticulum stress (ERS). In vivo, L-SF/SA accelerated the healing of infected wounds in SD rats. The L-SF/SA reduced the bacterial load, induced M2 polarization of macrophages, increased angiogenesis, regulated collagen ratio, and alleviated the ERS, thereby promoting scarless wound healing and increasing hair follicle regeneration. Therefore, probiotic-functionalized silk fibroin/alginate scaffolds showed potential in the infected wound healing.

Electrochemical deposition of Ppy/Dex/ECM coatings and their regulation on cellular responses through electrical controlled drug release

Bone tissue engineering requires a material that can simultaneously promote osteogenic differentiation and anti-inflammatory effects at specific times in response to a series of problems after bone implantation. In this study, the porous network-like titanium matrix was constructed and polypyrrole/dexamethasone (Ppy/Dex) composite coatings with three-dimensional nano-network structure were prepared by electrochemical deposition. The biocompatibility of the composite coatings was further improved by the composite of the extracellular matrix (ECM). The Ppy/Dex/ECM composite coatings released Dex by changing the redox state of Ppy under the electrical stimulation of negative pulses, achieving a drug release controlled by electric field. In terms of osteogenic differentiation, the Ppy/Dex/ECM composite coatings exhibited the best osteogenic activity under electrical controlled release, indicating the synergistic effect of Dex and ECM on osteogenic differentiation. In terms of anti-inflammatory properties, ECM exhibited simultaneous inhibition of both pro- and anti-inflammatory process, while Dex demonstrated significant promotion of anti-inflammatory processes. In this work, the effect of electrical controlled drug release on osteogenic differentiation and inflammation in the ECM cell microenvironment was achieved by preparing Ppy/Dex/ECM composite coatings, which is of great significance for bone tissue engineering and regenerative medicine.

Novel Titanium Implant: A 3D Multifunction Architecture with Charge-Trapping and Piezoelectric Self-Stimulation

Implant-associated infection and inflammation are the main causes of implant failure, causing irreversible damage and significantly increasing clinical risks and economic losses. In this study, a 3D multifunctional architecture is constructed that consisted of hierarchical TiO₂ nanotubes (NTs) and electrospun polyvinylidene fluoride nanofiber layers on the surface of a titanium implant. The movement of bacteria through the nanofiber layer is facilitated by its appropriate pore sizes and electrostatic interactions to reach the NT layer where the bacteria are killed by positive charge traps. In contrast, the macrophages tend to adhere to the nanofiber layer. The mechanical interactions between the macrophages and piezoelectric nanofibers generate a self-stimulated electric field that regulated an anti-inflammatory phenotype. This study provides a new method for multifunctional implant materials with antibacterial, piezoelectrically self-stimulated anti-inflammatory, and osteointegration properties that are driven by electrical stimulation.