Interfacial and Defect Polarization Enhanced Microwave Noninvasive Therapy for Staphylococcus aureus-Infected Chronic Osteomyelitis

A microenvironment responsive polyetheretherketone implant with antibacterial and osteoimmunomodulatory properties facilitates osseointegration

Failure of intraosseous prostheses is primarily attributed to implant loosening and infections. Current primary therapeutic modalities, such as antibiotics and local debridement, not only face challenges in thoroughly eliminating obstinate adhered bacteria but also encounter difficulties in ameliorating undue inflammatory reactions and regenerating impaired peri-implant bone tissues. Polyetheretherketone (PEEK) has excellent mechanical and physicochemical characteristics and has been used extensively as a medical biomaterial. However, the limited bactericidal and osseointegrative activities of bioinert PEEK restrict its clinical application. Herein, a microenvironment responsive coating with immobilised immunomodulatory magnesium ions (Mg2+) and disinfectant cerium oxide nanoparticles (CNPs) is designed via ion coordination mediated by polydopamine (PDA) and electrospinning based on collagen structure-bionic silk fibroin (SF). By utilising the pH responsiveness of SF, CNPs exhibit potent antibacterial effects in an acidic environment (pH 5.0) caused by local bacterial infection. Due to the chelation interaction with PDA and the constraint of SF, Mg2+ is slowly released, ameliorating the local immune microenvironment and boosting osteogenesis by upregulating M2 phenotype macrophages. Bioinformatics analysis indicates that the inflammation is suppressed via the NF-κB signaling pathway. Overall, this SF-based coating maximizes the synergistic effect of CNPs and Mg2+, offering enhanced antibacterial and osteoimmunomodulatory bioactivity for successful implantation.

Synergistic microwave hyperthermia treatment for subcutaneous deep in situ breast cancer using conformal array antennas and a microwave-thermal-sensitive nanomaterial

When microwave hyperthermia (MWH) array antenna technology is used to treat breast cancer, how to effectively target and heat deep tumors and reduce thermal damage to healthy tissues is still a challenge in clinical applications. In this study, the synergistic MWH effect of conformal-array antennas (CAA) and a novel microwave-thermal-sensitive nanomaterial (MTSN) was investigated for the treatment of subcutaneous deep in situ breast cancer. At the beginning of the study, the thermal damage score was used to evaluate the therapeutic efficacy of the CAA. It was found that although array antenna technology can achieve effective heating of deep tumors, its damage to healthy tissues is unacceptable. Consequently, we developed a novel MTSN, ZIF-8@HA, whose unique structure significantly enhanced the absorption of MW energy and MW thermal conversion efficiency in the local tumor region. The MW thermal conversion efficiency of ZIF-8@HA achieved was as high as 46.46% in in vivo MW heating experiments. In the phantom that simulates the electromagnetic environment of the human body, the microwave-thermal sensitization (MTS) effect is also significant, and the reduction in the average thermal damage score of healthy tissues by more than 10% was verified through measurements using the coaxial probe method and COMSOL simulations. Cellular experiments confirmed that the combination of ZIF-8@HA and MW irradiation could significantly reduce the survival rate of tumor cells. In addition, cross-tissue MW heating experiments revealed the advantages of ZIF-8@HA combined with the CAA. Finally, phantom experiments confirmed that the synergistic use of the CAA with ZIF-8@HA significantly accelerated the local heating rate of deep tumors, reduced the time required for the tumor region to achieve 100% thermal damage, and effectively minimized the thermal damage to healthy tissues.

Interface/Dipole Polarized Antibiotics-Loaded Fe3O4/PB Nanoparticles for Non-Invasive Therapy of Osteomyelitis Under Medical Microwave Irradiation

Due to their poor light penetration, photothermal therapy and photodynamic therapy are ineffective in treating deep tissue infections, such as osteomyelitis caused by Staphylococcus aureus (S. aureus). Here, a microwave (MW)-responsive magnetic targeting composite system consisting of ferric oxide (Fe3O4)/Prussian blue (PB) nanoparticles, gentamicin (Gent), and biodegradable poly(lactic-co-glycolic acid) (PLGA) is reported. The PLGA/Fe3O4/PB/Gent complex is used in combination with MW thermal therapy (MTT), MW dynamic therapy (MDT), and chemotherapy (CT) to treat acute osteomyelitis infected with S. aureus-infected. The powerful antibacterial effect of the PLGA/Fe3O4/PB/Gent is determined by the synergistic effects of heat and reactive oxygen species (ROS) generation by the Fe3O4/PB nanoparticles under MW irradiation and the effective release of Gent at the infection site via magnetic targeting. The antibacterial mechanism of the PLGA/Fe3O4/PB/Gent under MW irradiation is analyzed using bacterial transcriptome RNA sequencing. The MW heat and ROS reduce the activity of the protein transporters on the bacterial membrane, along with the transport of various ions and the acceleration of phosphate metabolism, which can lead to increased permeability of the bacterial membrane, damage the ribosome and DNA, and accompany the internal protein efflux of the bacteria, thus effectively killing the bacteria.

A Bacterial Capturing, Neural Network-Like Carbon Nanotubes/Prussian Blue/Puerarin Nanocomposite for Microwave Treatment of Staphylococcus Aureus-Infected Osteomyelitis

Staphylococcus aureus (S. aureus)-infected osteomyelitis is a deep tissue infection that cannot be effectively treated with antibiotics. Microwave (MW) thermal therapy (MTT) and MW dynamic therapy (MDT) based on MW-responsive materials are promising for the therapy of bacteria-infected osteomyelitis occurring in deep tissues that cannot be effectively treated with antibiotics. In this work, the MW-responsive system of carbon nanotubes (CNTs)/Prussian blue (PB)/puerarin (Pue) with stable network-like structures is constructed. The PB is grown in situ on the CNTs, and its introduction not only reduces the aggregation of the network-like structures of the CNTs, but the large specific surface area and mesoporous structure can also provide many active sites for the adsorption of oxygen and polar molecules. Pue is a natural anti-inflammatory material that reduces inflammation at the infection site. The composite of the CNTs and PB avoids the skin effect and thus can improve dielectric and reflection losses. The MW thermal response of CNTs/PB/Pue is mainly due to the occurrence of reflection loss, dielectric loss, multiple reflections and scattering, interface polarization, and dipole polarization. In addition, under MW irradiation, the CNTs/PB/Pue can produce reactive oxygen species (ROS), such as singlet oxygen (1O2), hydroxyl radical (·OH).

Defects-Rich Heterostructures Trigger Strong Polarization Coupling in Sulfides/Carbon Composites with Robust Electromagnetic Wave Absorption

Defects-rich heterointerfaces integrated with adjustable crystalline phases and atom vacancies, as well as veiled dielectric-responsive character, are instrumental in electromagnetic dissipation. Conventional methods, however, constrain their delicate constructions. Herein, an innovative alternative is proposed: carrageenan-assistant cations-regulated (CACR) strategy, which induces a series of sulfides nanoparticles rooted in situ on the surface of carbon matrix. This unique configuration originates from strategic vacancy formation energy of sulfides and strong sulfides-carbon support interaction, benefiting the delicate construction of defects-rich heterostructures in MxSy/carbon composites (M-CAs). Impressively, these generated sulfur vacancies are firstly found to strengthen electron accumulation/consumption ability at heterointerfaces and, simultaneously, induct local asymmetry of electronic structure to evoke large dipole moment, ultimately leading to polarization coupling, i.e., defect-type interfacial polarization. Such "Janus effect" (Janus effect means versatility, as in the Greek two-headed Janus) of interfacial sulfur vacancies is intuitively confirmed by both theoretical and experimental investigations for the first time. Consequently, the sulfur vacancies-rich heterostructured Co/Ni-CAs displays broad absorption bandwidth of 6.76 GHz at only 1.8 mm, compared to sulfur vacancies-free CAs without any dielectric response. Harnessing defects-rich heterostructures, this one-pot CACR strategy may steer the design and development of advanced nanomaterials, boosting functionality across diverse application domains beyond electromagnetic response.

Electron Aggregation and Oxygen Fixation Reinforced Microwave Dynamic and Thermal Therapy for Effective Treatment of MRSA-Induced Osteomyelitis

Antibiotics are frequently used to clinically treat osteomyelitis caused by bacterial infections. However, extended antibiotic use may result in drug resistance, which can be life threatening. Here, a heterojunction comprising Fe2O3/Fe3S4 magnetic composite is constructed to achieve short-term and efficient treat osteomyelitis caused by methicillin-resistant Staphylococcus aureus (MRSA). The Fe2O3/Fe3S4 composite exhibits powerful microwave (MW) absorption properties, thereby effectively converting incident electromagnetic energy into thermal energy. Density functional theory calculations demonstrate that Fe2O3/Fe3S4 possesses significant charge accumulation and oxygen-fixing capacity at the heterogeneous interface, which provides more active sites and oxygen sources for trapping electromagnetic hotspots. The finite element analysis indicates that Fe2O3/Fe3S4 displays a larger electromagnetism field enhancement parameter than Fe2O3 owing to a significant increase in electromagnetic hotspots. These hotspots contribute to charge differential accumulation and depletion motions at the interface, thereby augmenting the release of free electrons that subsequently combine with the oxygen adsorbed by Fe2O3/Fe3S4 to generate reactive oxygen species (ROS) and heat. This research, which achieves extraordinary bacterial eradication through the synergistic effect of microwave thermal therapy (MWTT) and microwave dynamic therapy (MDT), presents a novel strategy for treating deep-tissue bacterial infections.

MXene-Mediated Catalytic Redox Reactions for Biomedical Applications

Reactive oxygen species (ROS) play a crucial role in orchestrating a myriad of physiological processes within living systems. With the advent of materdicine, an array of nanomaterials has been intricately engineered to influence the redox equilibrium in biological milieus, thereby pioneering a distinctive therapeutic paradigm predicated on ROS-centric biochemistry. Among these, two-dimensional carbides, nitrides, and carbonitrides, collectively known as MXenes, stand out due to their multi-valent and multi-elemental compositions, large surface area, high conductivity, and pronounced local surface plasmon resonance effects, positioning them as prominent contributors in ROS modulation. This review aims to provide an overview of the advancements in harnessing MXenes for catalytic redox reactions in various biological applications, including tumor, anti-infective, and anti-inflammatory therapies. The emphasis lies on elucidating the therapeutic mechanism of MXenes, involving both pro-oxidation and anti-oxidation processes, underscoring the redox-related therapeutic applications facilitated by self-catalysis, photo-excitation, and sono-excitation properties of MXenes. Furthermore, this review highlights the existing challenges and outlines future development trends in leveraging MXenes for ROS-involving disease treatments, marking a significant step towards the integration of these nanomaterials into clinical practice.

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.

Nanotherapeutic System with Effective Microwave Sensitization and Pyroptosis Programming Enable Synergistic Microwave-Immunotherapy in Bladder Cancer

Currently, the prognosis for patients with advanced bladder cancer remains poor, with only a minority being sensitive to immune checkpoint inhibitors. There is a need to develop additional treatment strategies. Microwave therapy, as a promising approach for some inoperable tumors, still faces challenges such as limited efficacy and high recurrence rates. Additionally, the cell damage and necrosis induced by conventional microwave treatment only act as weak immunostimulatory factors for antitumor immunity, failing to activate effective antitumor immune responses. Recent discoveries have shown that inducing pyroptosis can provide a good opportunity for enhancing systemic immune responses and alleviating immune suppression in cancer therapy. Here, we have developed Mn-ZrMOF@DAC, a microwave-sensitized nanoparticle loaded with the DNA methylation inhibitor decitabine. The Mn-ZrMOF@DAC can enhance the effect of microwave thermal therapy and generate reactive oxygen species under microwave irradiation, causing thermal and oxidative damage to cancer cells. Furthermore, there was an important up-regulation of the key pyroptosis protein GSDME, with a marked increase in pyroptotic cell numbers. In vivo experiments demonstrated that mice injected with Mn-ZrMOF@DAC nanoparticles followed by microwave radiation treatment exhibited potent antitumor effects and enhanced the efficacy of anti-PD-1 therapy. This therapy not only enhanced the efficacy of microwave treatment, exhibiting significant antitumor effects, but also activated antitumor immunity by inducing pyroptosis, thus enhancing the efficacy of immunotherapy for bladder cancer. It holds promise for providing new avenues in the treatment of bladder cancer.