Search

Macrophage-mediated small Fe@Fe 3 O 4 nanoparticle delivery system was constructed to explore the effects of Fe@Fe 3 O 4 nanoparticle aggregation and the increasing tumor enrichment on MRI and MHT performance. [Display omitted] Magnetothermal therapy (MHT) has attracted significant attention due to the advantages of non-/minimal invasiveness, high efficiency, and excellent tissue penetration. However, developing small MHT agents (<50 nm) with excellent magnetothermal conversion performance and high tumor enrichment is a great challenge. Herein, a macrophage-mediated delivery of small Fe@Fe 3 O 4 -DHCA nanoparticles (∼14 nm) was designed for enhanced magnetic resonance imaging (MRI) and MHT of solid tumors. Based on the "Trojan horse" loading properties of the macrophages (RAW267.4 cells), the aggregation of Fe@Fe 3 O 4 -DHCA nanoparticles in the cells results in an enhanced MRI and magnetothermal performance in vitro. In addition, the MHT effect of RAW267.4 loaded with Fe@Fe 3 O 4 -DHCA in vivo is better than that of Fe@Fe 3 O 4 -DHCA alone, due to the tumor-targeting performance of RAW267.4 cells. This macrophage-mediated delivery provides a new strategy for the enhanced treatment effect of MHT based on Fe@Fe 3 O 4 -DHCA nanoparticles, and has great application potential for clinic tumor therapy. [ABSTRACT FROM AUTHOR]

Abstract One-dimensional (1D, wire- and fiber-shaped) supercapacitors have recently attracted interest due to their roll-up, micrometer size and potential applications in portable or wearable electronics. Herein, a 1D wire-shaped electrode was developed based on Fe3O4 nanosheet arrays connected on the Fe wire, which was prepared via oxidation of Fe wire in 0.1 M KCl solution (pH 3) with O2-rich environment under 70 °C. The obtained Fe3O4 nanosheet arrays displayed a high specific capacitance (20.8 mF cm−1 at 10 mV s−1) and long cycling lifespan (91.7% retention after 2500 cycles). The excellent performance may attribute to the connected nanosheet structure with abundant open spaces and the intimate contact between the Fe3O4 and iron substrate. In addition, a wire-shaped asymmetric supercapacitor was fabricated and had excellent capacitive properties with a high energy density (9 µWh cm−2) at power density of 532.7 µW cm−2 and remarkable long-term cycling performance (99% capacitance retention after 2000 cycles). Considering low cost and earth-abundant electrode material, as well as outstanding electrochemical properties, the assembled supercapacitor will possess enormous potential for practical applications in portable electronic device.

Iron (Fe)-based nanoparticles are extremely valuable in biomedical applications owing to their low toxicity and high magnetization values at room temperature. In this study, we synthesized nearly monodisperse iron oxide (Fe3O4) and Fe@Fe3O4 (core: Fe, shell: Fe3O nanoparticles in aqueous medium under argon flow and then, coated them with various biocompatible ligands and silica. In this study, eight types of surface-modified nanoparticles were investigated, namely, Fe3O4@PAA (PAA = polyacrylic acid; of PAA = 5100 amu and 15,000 amu), Fe3O4@PAA-FA (FA = folic acid; of PAA = 5100 amu and 15,000 amu), Fe3O4@PEI-fluorescein (PEI = polyethylenimine; of PEI = 1300 amu), Fe@Fe3O4@PEI ( of PEI = 10,000 amu), Fe3O4@SiO2 and Fe@Fe3O4@SiO2 nanoparticles. We characterized the prepared surface-modified nanoparticles using high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) absorption spectroscopy, a superconducting quantum interference device (SQUID), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy and confocal microscopy. Finally, we measured the cytotoxicity of the samples. The results indicate that the surface-modified nanoparticles are biocompatible and are potential candidates for various biomedical applications. [ABSTRACT FROM AUTHOR]

Targeted T 1 – T 2 MRI contrast agents, which can eliminate the difficulty of image matching across multiple imaging instruments and permit specific localization of lesions, are promising candidates for more accurate diagnosis of tumors. In this study, ultrasmall Fe@Fe 3 O 4 nanoparticles were designed and synthesized as T 1 – T 2 dual-mode MRI contrast agents for accurate tumor imaging. First, to investigate the influence of nanoparticle size, Fe@Fe 3 O 4 nanoparticles with diameters of 4, 8, and 12 nm were prepared, among which the 8 nm 3-(3,4-dihydroxyphenyl)propionic acid (DHCA)-modified nanoparticles exhibited the optimal T 1 – T 2 dual-mode MRI performance. Next, to develop a tumor-targeted contrast agent, the DHCA-Fe@Fe 3 O 4 nanoparticles were conjugated with the F56 peptide, which targets the vascular endothelial growth factor receptor, and the resulting F56-DHCA-Fe@Fe 3 O 4 nanoparticles were found to exhibit good T 1 – T 2 dual-mode imaging and tumor-targeting performance both in vitro and in vivo, indicating the nanoparticles represent a new research tool for accurate tumor diagnosis. F56-DHCA-Fe@Fe 3 O 4 nanoparticles were designed and synthesized as a T 1 – T 2 dual-mode targeted MRI contrast agent. First, 8 nm DHCA-Fe@Fe 3 O 4 nanoparticles performed good dual-mode MRI effect. Secondly, the F56 peptide on the surface of DHCA-Fe@Fe 3 O 4 nanoparticles can bind to vascular endothelial growth factor receptor 1 (VEGFR1), which is highly expressed in tumor vascular endothelial cells. The nanoparticles exhibited good dual-mode MRI performance both in vitro and in vivo with tumor-targeting properties. [Display omitted] • Ultrasmall Fe@Fe 3 O 4 nanoparticles were synthesized for T 1 – T 2 dual-mode MRI. • Particle size affected the MRI performance. • Attachment of the F56 peptide enhanced tumor accumulation for targeted imaging. [ABSTRACT FROM AUTHOR]