Metal Ion Coordination Improves Graphite Nitride Carbon Microwave Therapy in Antibacterial and Osteomyelitis Treatment

Tailoring osteoimmunity and hemostasis using 3D-Printed nano-photocatalytic bactericidal scaffold for augmented bone regeneration

Bone hemorrhage, infection, and large bone defects following surgical treatment of traumatic bone injury have raised potential concerns, underscoring the urgent need to develop multifunctional therapeutic platforms that can effectively address traumatic bone regeneration. Advancements in three-dimensional (3D) printing technology have propelled the development of several engineering disciplines, such as tissue engineering. Nevertheless, 3D-printed frameworks with conventional materials often lack multifunctional capabilities to promote specific activities for diverse regeneration purposes. In this study, we developed a highly oxidized two-dimensional (2D) graphitic carbon nitride (Ox-gCN) as a nano-photocatalyst to reinforce alginate/gelatin (ALG)-based hydrogel scaffolds (ALG/CN) to achieve an anti-inflammatory and osteo-immunomodulatory niche with superior hemostatic ability for traumatic bone injury repair. Sulfuric acid oxidation enhances the oxygen-containing functional groups of the g-CN surface and promotes cell adhesion and differentiation of human bone marrow-derived mesenchymal stem cells (hBMSCs) in vitro. Moreover, the excellent visible light-activated photocatalytic characteristics of the ALG/CN scaffold were used in antibacterial studies. In addition, the ALG/CN bio/nanocomposite scaffold facilitates M2 polarization of macrophages than did pristine ALG scaffolds. Furthermore, ALG/CN scaffold induced hBMSCs differentiation by upregulating ERK and MAPKs phosphorylation during osteo-immunomodulation. In a rat calvaria defect model, the fabricated ALG/CN scaffolds induced new bone formation through collagen deposition and activation of osteocalcin proteins without inflammation in vivo. These results highlight the potential of 3D-printed functionalized 2D carbon nitrides in regulating the bone immune microenvironment, which may be beneficial for developing advanced tissue constructs, especially for traumatic bone regeneration in clinical settings.

Semiconductor photocatalytic antibacterial materials and their application for bone infection treatment

Bacterial infection in bone tissue engineering is a severe clinical issue. Traditional antimicrobial methods usually cause problems such as bacterial resistance and biosecurity. Employing semiconductor photocatalytic antibacterial materials is a more controlled and safer strategy, wherein semiconductor photocatalytic materials generate reactive oxygen species under illumination for killing bacteria by destroying their cell membranes, proteins, DNA, etc. In this review, P-type and N-type semiconductor photocatalytic materials and their antibacterial mechanisms are introduced. Type II heterojunctions, P-N heterojunctions, type Z heterojunctions and Schottky junctions have been reported to reduce the recombination of carriers, while element doping, sensitization and up-conversion luminescence expand the photoresponse range. Furthermore, the applications of semiconductor photocatalytic antibacterial materials in bone infection treatment such as osteomyelitis treatment, bone defect repair and dental tissue regeneration are summarized. Finally, the conclusion and future prospects of semiconductor photocatalytic antibacterial materials in bone tissue engineering were analyzed.

Stimuli-responsive and targeted nanomaterials: Revolutionizing the treatment of bacterial infections

Bacterial infections have emerged as a major threat to global public health. The effectiveness of traditional antibiotic treatments is waning due to the increasing prevalence of antimicrobial resistance, leading to an urgent demand for alternative antibacterial technologies. In this context, antibacterial nanomaterials have proven to be powerful tools for treating antibiotic-resistant and recurring infections. Targeting nanomaterials not only enable the precise delivery of bactericidal agents but also ensure controlled release at the infection site, thereby reducing potential systemic side effects. This review collates and categorizes nanomaterial-based responsive and precision-targeted antibacterial strategies into three key types: exogenous stimuli-responsive (including light, ultrasound, magnetism), bacterial microenvironment-responsive (such as pH, enzymes, hypoxia), and targeted antibacterial action (involving electrostatic interaction, covalent bonding, receptor-ligand mechanisms). Furthermore, we discuss recent advances, potential mechanisms, and future prospects in responsive and targeted antimicrobial nanomaterials, aiming to provide a comprehensive overview of the field's development and inspire the formulation of novel, precision-targeted antimicrobial strategies.

Advanced Piezoelectric Materials, Devices, and Systems for Orthopedic Medicine

Harnessing the robust electromechanical couplings, piezoelectric materials not only enable efficient bio-energy harvesting, physiological sensing and actuating but also open enormous opportunities for therapeutic treatments through surface polarization directly interacting with electroactive cells, tissues, and organs. Known for its highly oriented and hierarchical structure, collagen in natural bones produces local electrical signals to stimulate osteoblasts and promote bone formation, inspiring the application of piezoelectric materials in orthopedic medicine. Recent studies showed that piezoelectricity can impact microenvironments by regulating molecular sensors including ion channels, cytoskeletal elements, cell adhesion proteins, and other signaling pathways. This review thus focuses on discussing the pioneering applications of piezoelectricity in the diagnosis and treatment of orthopedic diseases, aiming to offer valuable insights for advancing next-generation medical technologies. Beginning with an introduction to the principles of piezoelectricity and various piezoelectric materials, this review paper delves into the mechanisms through which piezoelectric materials accelerated osteogenesis. A comprehensive overview of piezoelectric materials, devices, and systems enhancing bone tissue repair, alleviating inflammation at infection sites, and monitoring bone health is then provided, respectively. Finally, the major challenges faced by applications of piezoelectricity in orthopedic conditions are thoroughly discussed, along with a critical outlook on future development trends.

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

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

Zinc-doped bioactive glass-functionalized polyetheretherketone to enhance the biological response in bone regeneration

Polyether ether ketone (PEEK) is gaining recognition as a highly promising polymer for orthopedic implants, attributed to its exceptional biocompatibility, ease of processing, and radiation resistance. However, its long-term in vivo application faces challenges, primarily due to suboptimal osseointegration from postimplantation inflammation and immune reactions. Consequently, biofunctionalization of PEEK implant surfaces emerges as a strategic approach to enhance osseointegration and increase the overall success rates of these implants. In our research, we engineered a multifaceted PEEK implant through the in situ integration of chitosan-coated zinc-doped bioactive glass nanoparticles (Zn-BGNs). This novel fabrication imbues the implant with immunomodulatory capabilities while bolstering its osseointegration potential. The biofunctionalized PEEK composite elicited several advantageous responses; it facilitated M2 macrophage polarization, curtailed the production of inflammatory mediators, and augmented the osteogenic differentiation of bone marrow mesenchymal stem cells. The experimental findings underscore the vital and intricate role of biofunctionalized PEEK implants in preserving normal bone immunity and metabolism. This study posits that utilizing chitosan-BGNs represents a direct and effective method for creating multifunctional implants. These implants are designed to facilitate biomineralization and immunomodulation, making them especially apt for orthopedic applications.

A composite hydrogel loaded with the processed pyritum promotes bone repair via stimulate the osteogenic differentiation of BMSCs

Tissue engineering shows promise in repairing extensive bone defects. The promotion of proliferation and osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) by biological scaffolds has a significant impact on bone regeneration outcomes. In this study we used an injectable hydrogel, known as aminated mesoporous silica gel composite hydrogel (MSNs-NH2@GelMA), loaded with a natural drug, processed pyritum (PP), to promote healing of bone defects. The mechanical properties of the composite hydrogel were significantly superior to those of the blank hydrogel. In vitro experiments revealed that the composite hydrogel stimulated the osteogenic differentiation of BMSCs, and significantly increased the expression of type I collagen (Col 1), runt-related transcription factor 2 (Runx 2), alkaline phosphatase (ALP), osteocalcin (OCN). In vivo experiments showed that the composite hydrogel promoted the generation of new bones. These findings provide evidence that the composite hydrogel pyritum-loaded holds promise as a biomaterial for bone repair.

Magnetic Bimetallic Heterointerface Nanomissiles with Enhanced Microwave Absorption for Microwave Thermal/Dynamics Therapy of Breast Cancer

Microwave thermotherapy (MWT) has shown great potential in cancer treatment due to its deep tissue penetration and minimally invasive nature. However, the poor microwave absorption (MA) properties of the microwave thermal sensitizer in the medical frequency band significantly limit the thermal effect of MWT and then weaken the therapeutic efficacy. In this paper, a Ni-based multilayer heterointerface nanomissile of MOFs-Ni-Ru@COFs (MNRC) with improved MA performance in the desired frequency band via introducing magnetic loss and dielectric loss is developed for MWT-based treatment. The loading of the Ni nanoparticle in MNRC mediates the magnetic loss, introducing the MA in the medical frequency band. The heterointerface formed in the MNRC by nanoengineering induces significant interfacial polarization, increasing the dielectric loss and then enhancing the generated MA performance. Moreover, MNRC with the strong MA performance in the desired frequency range not only enhances the MW thermal effect of MWT but also facilitates the electron and energy transfer, generating reactive oxygen species (ROS) at tumor sites to mediate microwave dynamic therapy (MDT). The strategy of strengthening the MA performance of the sensitizer in the medical frequency band to improve MWT-MDT provides a direction for expanding the clinical application of MWT in tumor treatment.