Synthesis of manganese doped β-FeOOH and MnFe2O4 nanorods for enhanced drug delivery and hyperthermia application

Magnetically triggered thermoelectric heterojunctions with an efficient magnetic-thermo-electric energy cascade conversion for synergistic cancer therapy

Thermoelectric therapy has been emerging as a promising and versatile strategy for targeting malignant tumors treatment. However, the lack of effective time-space controlled triggering of thermoelectric effect in vivo limits the application of thermoelectric therapy. Here a magnetically triggered thermoelectric heterojunction (CuFe2O4/SrTiO3, CFO/STO) for synergistic thermoelectric/chemodynamic/immuno-therapy is developed. The efficient magnetothermal nanoagent (CFO) is synthesized using the hydrothermal method, and thermoelectric nanomaterials (STO) are grown on its surface to create the heterojunction. To enhance oral delivery efficiency, a fusion membrane (M) of Staphylococcus aureus and macrophage cell membranes are coated the CFO/STO heterojunction, enabling effective targeting of orthotopic colorectal cancer. Once the CFO/STO@M reaches the tumor region, in vitro alternating magnetic field (AMF) stimulation activates the catalytic treatment through a magnetic-thermo-electric energy cascade conversion effect. Additionally, the immunogenic death of tumor cells, down-regulating vascular endothelial growth factor and heat shock protein HSP70, increasing expression of endothelial cell adhesion molecule (ICAM-1/VCAM-1), and M1 polarization of macrophages contribute to tumor immunotherapy. Overall, the magnetically triggered thermoelectric heterojunction based on CFO/STO@M shows remarkable antitumor capability in female mice, offering a promising approach to broaden both the scope of application and the effectiveness of catalytic therapy.

Effect of small amounts of akaganeite (β-FeOOH) nanorods on the gelation, phase behaviour and injectability of thermoresponsive Pluronic F127

Pluronic F127 (PF127) is a copolymer with an amphiphilic nature and can self-assemble to form micelles and, beyond 20% (w/v), form a thermoresponsive physical gel state. However, they are mechanically weak and easily dissolve in physiological environments, which limits their use in load-bearing in specific biomedical applications. Therefore, we propose a pluronic-based hydrogel with enhanced stability by incorporating small amounts of paramagnetic nanorods, akaganeite (β-FeOOH) nanorods (NRs) of aspect ratio ∼7, with PF127. Due to their weak magnetic properties, β-FeOOH NRs have been used as a precursor for preparing stable iron-oxide states (e.g., hematite and magnetite), and the studies on β-FeOOH NRs to be used as a primary component in hydrogels are at the nascent stage. Here we report a method to synthesize β-FeOOH NRs on a gram scale using a simple sol-gel process and characterize the NRs with various techniques. A phase diagram and thermoresponsive behaviour based on rheological experiments and visual observations are proposed for 20% (w/v) PF127 with low concentrations (0.1-1.0% (w/v)) of β-FeOOH NRs. We observe a unique non-monotonous behaviour in the gel network represented by various rheological parameters like storage modulus, yield stress, fragility, high-frequency modulus plateau, and characteristic relaxation time as a function of nanorod concentration. A plausible physical mechanism is proposed to fundamentally understand the observed phase behaviour in the composite gels. These gels show thermoresponsiveness and enhanced injectability, and could find applications in tissue engineering and drug delivery.

Carboxylated PEG-Functionalized MnFe2O4 Nanocubes Synthesized in a Mixed Solvent: Morphology, Magnetic Properties, and Biomedical Applications

Ferrites are one of the most studied materials around the globe due to their distinctive biological and magnetic properties. In the same line, anisotropic MnFe2O4 nanoparticles have been explored as a potential candidate possessing excellent magnetic properties, biocompatibility, and strong magnetic resonance imaging (MRI) properties such as r2 relaxivity for magnetic field-guided biomedical applications. The current work reports the synthesis and morphological evolution of MnFe2O4 nanocubes (MNCs) in a hydrothermal process using different volume ratios of water and ethanol. The synthesis protocol was designed to influence the properties of the ferrite nanocubes, for example, the variation in surface tension, dielectric properties, and the ionic character of the solvent, and this has been achieved by adding ethanol into water during the synthesis. Pristine MnFe2O4 is formed with well-defined cubic to irregular cubic shapes with the addition of ethanol, as evidenced from XRD, field emission scanning electron microscopy, and porosity measurements. MNCs have been investigated for magnetic hyperthermia and MRI applications. Well-defined cubic-shaped MNCs with uniform size distribution possessed a high saturation magnetization of 63 emu g-1 and a transverse relaxivity (r2) of 216 mM-1 s-1 (Mn + Fe). Furthermore, the colloidal nanocubes showed concentration-dependent hyperthermic response under an alternating magnetic field. The MNCs are biocompatible but advantageously show anticancer activities on breast cancer MCF 7 and MDA-MB-231 cells.