Search

Magnetic nanoparticles (MNPs) are gaining much attention due to their applications in specialized fields, including diagnosis, bioimaging, drug delivery, and cell therapy. In recent years, the field of stem cell and regenerative medicine comprising tissue engineering and drug delivery has been powered by nanoparticles. Particularly, mesenchymal stem cells (MSCs) are characterized with adequate immunomodulatory potential coupled with an excellent regenerative ability that contributes to improved therapy of various diseases. For clinical applications of MSCs, tracking and labeling are crucial to determine cell homing and distribution. Therefore, due to the high potential of MNPs in stem cell therapy, this review comprehensively uncovers the advancements in the respective field. Also, it discusses the usage of surface-functionalized materials in improving the physicochemical properties of MNPs, making them suitable candidates for several biomedical applications. Moreover, we have discussed that these nanoparticles within applied magnetic field and electromagnetic field have been considered multifunctional agents for labeling, stimulating, tracking, and targeting stem cells in vitro and in vivo. Additionally, the discussion comprises the progress and challenges associated with MNPs used as effective therapeutic, delivery, and diagnostic agents to treat cancer, cardiovascular, neurodegenerative, and bone-related disorders. Finally, the review discussed that the magnetic nanoparticles have also been widely used for targeted cancer cell therapy due to mechanical force for killing cancer cells under a magnetic field. It is concluded that the mechanical force produced by MNPs in a low-frequency vibrating magnetic field is the most promising and safe option for the destruction of tumor cells. In short, this review summarized the role of magnetic nanomaterials for effective, safe, and efficient nanomaterial-cell-based therapies. [ABSTRACT FROM AUTHOR]

Synthesizing oxygen evolution reaction (OER) catalysts with enhanced activity by codoping has been proven to be a feasible approach for the efficient use of noble metals via renewing their basic intrinsic properties. In continuation of the research in codoping, we prepare a ruthenium-based bimetallic doped catalyst Mn x Fe y Ru 1- x - y O 2 with an outstanding OER activity as compared to pure RuO 2 , one of the state-of-the-art OER catalysts. The synthesized codoped RuO 2 with a Mn/Fe molar ratio of 1 reflected a Tafel slope of only 41 mV dec -1 , which is appreciably lower than 64 mV dec -1 for pure RuO 2 . The X-ray photoelectron spectroscopy (XPS) performed reveals that oxygen vacancy and manganese valency are the key factors of the OER activity for codoped catalysts., Competing Interests: The authors declare no competing financial interest., (Copyright © 2020 American Chemical Society.)

We systematically characterized the perovskite-like oxides Ca 2 IrO 4 and CaIrO 3 as the oxygen evolution reaction (OER) catalysts. Compared with IrO 2 , universally accepted as the current state-of-the-art OER catalyst, Ca 2 IrO 4 showed an excellent OER catalytic activity in an acidic environment, whereas CaIrO 3 did not. X-ray photoelectron spectroscopy (XPS) spectra showed that the oxidation of iridium in Ca 2 IrO 4 and CaIrO 3 was slightly beyond +4. X-ray absorption near-edge structure (XANES) spectra illustrated that the IrO 6 octahedral geometric structure in Ca 2 IrO 4 and CaIrO 3 showed differences. The IrO 6 octahedral is asymmetrically distorted and uniformly compressed in Ca 2 IrO 4 and CaIrO 3 . Therefore, we propose that the IrO 6 octahedral distortion plays an important role in the OER activities., Competing Interests: The authors declare no competing financial interest.

Developing more efficient and stable oxygen evolution reaction (OER) catalysts is critical for future energy conversion and storage technologies. We demonstrate that inducing a lattice strain in IrO 2 crystal structure due to interface lattice mismatch enables an enhancement of the OER catalytic activity. The lattice strain is obtained by the direct growth of IrO 2 nanoparticles on a specially exposed surface of α-MnO 2 nanorods via a simple two-step hydrothermal synthesis. Interestingly, the prepared hydride OER activity increases with a lower IrO 2 grown mass, which offers an opportunity to reduce the usage of precious iridium and ultimately obtains a specific mass activity of 3.7 times than that of IrO 2 prepared under the same conditions and exhibits equivalent stability. The lattice mismatch in the underlying interface induces the formation of lattice strain in IrO 2 rather than the charge transfer between the materials. The lattice strain changes are in good agreement with the order of the OER activity. Our experimental results indicate that using the special exposed surface substrates or tuning the supporting morphology structure can manipulate the catalyst materials lattice strain for the design of more efficient OER catalysts.