The Synthesis of Size-Adjustable Superparamagnetism Fe3O4 Hollow Microspheres

Scutellarin-loaded pH/H2O2 dual-responsive polymer cyclodextrin mesoporous silicon framework nanocarriers for enhanced cancer therapy

Stimulus-responsive nanomaterials, particularly with targeting capabilities, have garnered significant attention in the cancer therapy. However, the biological safety of these innovative materials in vivo remains unknown, posing a hurdle to their clinical application. Here, a pH/H2O2 dual-responsive and targeting nano carrier system (NCS) was developed using core shell structure of Fe3O4 mesoporous silicon (MSN@Fe3O4) as main body, scutellarin (SCU) as antitumor drug and polymer cyclodextrin (PCD) as molecular switch (denoted as PCD@SCU@MSN@Fe3O4, abbreviated as NCS). The NCS, with an average particle size of 100 nm, displayed exceptional SCU loading capacity, a result of its uniform radial channel structure. The in vitro investigation under condition of pH and H2O2 indicated that NCS performed excellent pH/H2O2-triggered SCU release behavior. The NCS displayed a higher cytotoxicity against tumor cells (Huh7 and HCT116) due to its pH/H2O2 dual-triggered responsiveness, while the PCD@MSN@Fe3O4 demonstrated lower cytotoxicity for both Huh7 and HCT116 cells. In vivo therapeutic evaluation of NCS indicates significant inhibition of tumor growth in mouse subcutaneous tumor models, with no apparent side-effects detected. The NCS not only enhances the bioavailability of SCU, but also utilizes magnetic targeting technology to deliver SCU accurately to tumor sites. These findings underscore the substantial clinical application potential of NCS.

Multifunctional magnetocaloric bone cement with a time-varying alkaline microenvironment for sequential bacterial inhibition, angiogenesis and osteogenesis

Repairing infected bone defects remains a severe challenge due to antibiotic abuse and recurrence. Hence, we modified magnetocaloric Fe3O4 nanoparticles and added them to magnesium calcium phosphate bone cement (MCPC) to fabricate multifunctional magnetic composites for sequential bacterial inhibition, angiogenesis and osteogenesis. Nevertheless, high doses of Mg ions and Fe ions were released from MCPC, which adversely affected osteogenesis. Thus, Fe3O4 was modified using gelatin according to the emulsification crosslinking method, which exhibited a controllable magnetocaloric effect and degradation behavior, and favorable anti-bacterial ability under the action of an alternating magnetic field (AMF). In the early stage, the residual MgO created a local strong alkaline microenvironment by hydrolysis, which inhibited the function and activity of S. aureus and E. coli. At the later stage, the MCPC composites were controllably degraded under the function of gelatin and maintained a long-term local slight alkaline microenvironment that promoted the osteogenic differentiation and mineralization of BMSCs. In vivo subcutaneous implantation experiments further indicated that MCPC composites showed good biocompatibility and facilitated angiogenesis, presenting a promising future in magnetic materials design and infectious bone defect repair.

Mobile mechanical signal generator for macrophage polarization

The importance of mechanical signals in regulating the fate of macrophages is gaining increased attention recently. However, the recently used mechanical signals normally rely on the physical characteristics of matrix with non-specificity and instability or mechanical loading devices with uncontrollability and complexity. Herein, we demonstrate the successful fabrication of self-assembled microrobots (SMRs) based on magnetic nanoparticles as local mechanical signal generators for precise macrophage polarization. Under a rotating magnetic field (RMF), the propulsion of SMRs occurs due to the elastic deformation via magnetic force and hydrodynamics. SMRs perform wireless navigation toward the targeted macrophage in a controllable manner and subsequently rotate around the cell for mechanical signal generation. Macrophages are eventually polarized from M0 to anti-inflammatory related M2 phenotypes by blocking the Piezo1-activating protein-1 (AP-1）-CCL2 signaling pathway. The as-developed microrobot system provides a new platform of mechanical signal loading for macrophage polarization, which holds great potential for precise regulation of cell fate.

Mesoporous hollow Fe3O4 nanoparticles regulate the behavior of neuro-associated cells through induction of macrophage polarization in an alternating magnetic field

Magnetic iron oxide nanoparticles have shown great research value in the field of nerve regeneration because of their characteristics of satisfactory material properties and their ability to be stimulated by an external magnetic field to enhance the function of all aspects. Nevertheless, the impact of magnetic iron oxide nanoparticles on nerve regeneration regulated by macrophage polarization has not been well studied, and it is also not clear whether the introduction of the magnetic field has a further effect. Therefore, mesoporous hollow Fe₃O₄ nanoparticles (MHFPs) were synthesized. We selected an alternating magnetic field (AMF) because it may confer a stronger effect on MHFPs as compared to a static magnetic field, and then explored the field's ability to induce macrophage polarization. Furthermore, the effects of this regulation on other neuro-associated cells were also explored. Our results suggest that MHFPs can efficiently induce polarization of macrophages at the concentration of 40 μg mL^-1, upregulate the expression of related genes and cytokines, and further promote the proliferation of neural stem cells and the subsequent migration of vascular endothelial cells. These effects were significantly enhanced after the application of an AMF. This work also showed that the internalization of particles is the starting point for polarization regulation.

Iron oxide Nanoparticles (IONPs) with photothermal performance and enhanced nanozyme activity for bacteria-infected wound therapy

Metal-based nanomaterials usually have broad-spectrum antibacterial properties, low biological toxicity, and no drug resistance due to their intrinsic enzyme-like catalytic properties and external field (magnetic, thermal, acoustic, optical, electrical) responsiveness. Herein, Iron oxide (Fe3O4) nanoparticles (IONPs) synthesized by us have good biosafety, excellent photothermal conversion ability, and peroxidase-like catalytic activity, which can be used to construct a photothermal-enzymes combined antibacterial treatment platform. IONPs with peroxide-like catalytic activity can induce H2O2 to catalyze the production of •OH in a slightly acidic environment, thus achieving certain bactericidal effects and increasing the sensitivity of bacteria to heat. When stimulated by NIR light, the photothermal effect could destroy bacterial cell membranes, resulting in cleavage and inactivation of bacterial protein, DNA, or RNA. Meanwhile, it can also improve the catalytic activity of peroxidase-like, and promote IONPs to catalyze the production of more •OH for killing bacteria. After IONPs synergistic treatment, the antibacterial rate of Escherichia coli and Staphylococcus aureus reached nearly 100%. It also has an obvious killing effect on bacteria in infected wounds of mice, and can effectively promote the healing of S. aureus-infected wounds, which has great application potential in clinical anti-infection treatment.

Current Researches on Nanodrug Delivery Systems in Bladder Cancer Intravesical Chemotherapy

Bladder cancer is one of the most common malignant tumors in urinary system. Intravesical chemotherapy is a common adjuvant therapy after transurethral resection of bladder tumors. However, it has several disadvantages such as low drug penetration rate, short residence time, unsustainable action and inability to release slowly, thus new drug delivery and new modalities in delivery carriers need to be continuously explored. Nano-drug delivery system is a novel way in treatment for bladder cancer that can increase the absorption rate and prolong the duration of drug, as well as sustain the action by controlling drug release. Currently, nano-drug delivery carriers mainly included liposomes, polymers, and inorganic materials. In this paper, we reveal current researches in nano-drug delivery system in bladder cancer intravesical chemotherapy by describing the applications and defects of liposomes, polymers and inorganic material nanocarriers, and provide a basis for the improvement of intravesical chemotherapy drugs in bladder cancer.

Enhanced Antimalarial Efficacy Obtained by Targeted Delivery of Artemisinin in Heparin-Coated Magnetic Hollow Mesoporous Nanoparticles

Malaria is one of the deadliest infectious diseases threatening half of the world population. With the deterioration of the parasiticidal effect of the current antimalarials, novel approaches such as screening of more specific inhibitors and targeted delivery of drugs have been under intensive research. Herein, we prepare hollow mesoporous ferrite nanoparticles (HMFNs) of 200 nm with ferromagnetic properties using a one-pot hydrothermal reaction. A magnetically targeted drug-delivery system coloaded with artemisinin in the inner magnetite shell and heparin on the outer mesoporous shell (HMFN@ART@HEP) is developed. Specific targeting of the magnetic nanoparticles to the parasite-infected erythrocytes is achieved by the attraction between the HMFNs and hemozoin (paramagnetic), a vital metabolite of plasmodium in the erythrocytic stage. With the hemozoin production reaching the maximum during the schizont period of the parasite, HMFN@ART@HEPs are adsorbed to the infected red blood cells (iRBCs), which not only interferes with the release of merozoites but also significantly enhances the inhibitory efficacy due to the increased local concentration of artemisinin. Subsequently, the heparin coated on the surface of the nanoparticles can efficiently interfere with the invasion of freshly released merozoites to new RBCs through the specific interaction between the parasite-derived ligands and heparin, which further increases the inhibitory effect on malaria. As a cluster of heparin, heparin-coated nanoparticles provide stronger blocking capability than free heparin, resulting from multivalent interactions with surface receptors on merozoite. Thus, we have developed a HMFN-based delivery system with considerable antimalarial efficacy, which is a promising platform for treatment against malaria.

The antibacterial and antibiofilm activities of mesoporous hollow Fe3O4 nanoparticles in an alternating magnetic field

Unrestricted usage of antibiotics has accelerated the emergence of new strains of microorganisms with antimicrobial resistance (AMR) and the development of therapeutic technologies that do not rely only on antibiotics. Herein, mesoporous hollow Fe₃O₄ nanoparticles (MHFPs) were synthesized by a one-pot hydrothermal method, and the feasibility and possible mechanism of using alternating magnetic field (AMF) with MHFPs to kill Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were explored. The presence of the AMF (2.5 kW, 210 kHz) combined with the MHFPs resulted in a dramatic decrease in colony forming units (CFU) for E. coli and S. aureus in 25 min compared with the pure MHFPs at concentrations of 500, 800 and 1000 μg mL^-1. Macroscopic hyperthermia was proved not to be the sole reason for the phenomenon. Visible membrane damage was demonstrated by live/dead staining, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) assays. Besides, the permeability and integrity changes of the cell membrane were then quantitatively confirmed by measuring the relative electrical conductivity. In addition, bacterial biofilms were significantly dispersed in the presence of MHFPs and AMF. These results suggested that under the mediation of AMF, MHFPs can potentially serve as an efficient nonantibiotic therapeutic platform to disperse bacterial biofilms and inactivate bacteria by damaging the cell membrane of the bacteria.

Recent Advances in Magnetite Nanoparticle Functionalization for Nanomedicine

Functionalization of nanomaterials can enhance and modulate their properties and behaviour, enabling characteristics suitable for medical applications. Magnetite (Fe3O4) nanoparticles are one of the most popular types of nanomaterials used in this field, and many technologies being already translated in clinical practice. This article makes a summary of the surface modification and functionalization approaches presented lately in the scientific literature for improving or modulating magnetite nanoparticles for their applications in nanomedicine.

Magnetically targeted co-delivery of hydrophilic and hydrophobic drugs with hollow mesoporous ferrite nanoparticles

A magnetically targeted drug delivery system (DDS) is developed to solve the delivery problem of hydrophobic drugs by using hollow mesoporous ferrite nanoparticles (HMFNs). The HMFNs are synthesized by a one-pot hydrothermal method based on the Ostwald ripening process. The biocompatibility of the synthesized HMFNs was determined by MTT assay, lactate dehydrogenase (LDH) leakage assay and hemolyticity against rabbit red blood cells. Moreover, Prussian blue staining and bio-TEM observations showed that the cell uptake of nanocarriers was in a dose and time-dependent manner, and the nanoparticles accumulate mostly in the cytoplasm. A typical highly hydrophobic anti-tuberculosis drug, rifampin (RFP) was loaded into HMFNs using supercritical carbon dioxide (SC-CO₂) impregnation, and the drug loading amount reached as high as 18.25 wt%. In addition, HMFNs could co-encapsulate and co-deliver hydrophobic (RFP) and hydrophilic (isoniazide, INH) drugs simultaneously. The in vitro release tests demonstrated extra sustained co-release profiles of rifampicin and isoniazide from HMFNs. Based on this novel design strategy, the co-delivery of drugs in the same carrier enables a drug delivery system with efficient enhanced chemotherapeutic effect.

A magnetically targeted drug delivery system (DDS) is developed to solve the delivery problem of hydrophobic drugs by using hollow mesoporous ferrite nanoparticles (HMFNs).

Preparation and Photocatalytic Performance of Hollow Structure LiNb3O8 Photocatalysts

Hollow structure LiNb₃O₈ photocatalysts were prepared by a hydrothermal method assisting sintering process. The particles' aggregation to form hollow structures with obvious cavities can be attributed to the Li element volatilization during calcination process. All the LiNb₃O₈ powders show high photocatalytic efficiency of degradation of methylene blue (MB), especially for the sample calcined at 700 °C (LNO700), with only 3 h to completely decompose MB. The photo-degradation of MB follows the pseudo-first-order kinetics, and the obtained first-order rate is 0.97/h. The larger degradation rate of LNO700 can be attributed to its hollow structure which provides a larger specific surface area and more active sites to degrade the MB molecules. The cycling test of photo-degradation and adsorption of MB over LNO700 powder indicates that the hollow structure of the LiNb₃O₈ photocatalyst is stable and the LiNb₃O₈ photocatalyst is an efficient photocatalyst with good reusability, confirmed by the XRD and X-ray photoelectron spectroscopy tests before and after photo-degradation of MB.