An Electromagnetic Steering System for Magnetic Nanoparticle Drug Delivery

Targeted delivery of pharmaceutical agents to the brain using magnetic nanoparticles (MNPs) is an efficient technique to transport molecules to disease locations. MNPs can cross the blood–brain barrier (BBB) and can be concentrated at a specific location in the brain using non-invasive electromagnetic forces. The proposed EMA consists of two coil-core system. The cores are added in the center of each coil to concentrate the flux in the region of interest. The EMA can enhance the gradient field 10 times compared to only coil system and generate the maximum magnetic field of 160 mT and 5.6 T/m. A 12-kW direct-current power supply was used to generate sufficient magnetic forces on the MNPs by regulating the input currents of the coils. Effective guidance of MNPs is demonstrated via simulations and experiments using 800-nm-diameter MNPs in a Y-shaped channel. The developed EMA system has high potentials to increase BBB crossing of MNPs for efficient drug targeting to brain region

Ruthenium anchored on carbon nanotube electrocatalyst for hydrogen production with enhanced Faradaic efficiency

Developing efficient and stable electrocatalysts is crucial for the electrochemical production of pure and clean hydrogen. For practical applications, an economical and facile method of producing catalysts for the hydrogen evolution reaction (HER) is essential. Here, we report ruthenium (Ru) nanoparticles uniformly deposited on multi-walled carbon nanotubes (MWCNTs) as an efficient HER catalyst. The catalyst exhibits the small overpotentials of 13 and 17 mV at a current density of 10 mA cm(-2) in 0.5M aq. H2SO4 and 1.0M aq. KOH, respectively, surpassing the commercial Pt/C (16 mV and 33 mV). Moreover, the catalyst has excellent stability in both media, showing almost "zeroloss" during cycling. In a real device, the catalyst produces 15.4% more hydrogen per power consumed, and shows a higher Faradaic efficiency (92.28%) than the benchmark Pt/C (85.97%). Density functional theory calculations suggest that Ru-C bonding is the most plausible active site for the HER

Functionalized Magnetic Force Enhances Magnetic Nanoparticle Guidance: From Simulation to Crossing of the Blood-Brain Barrier in vivo

In recent studies, we introduced the concept of functionalized magnetic force as a method to prevent nanoparticles from sticking to vessel walls caused by extensive simulation and in vitro experiments involving a Y-shaped channel. In this study, we further investigated the effectiveness of the functionalized magnetic force with a realistic 3D vessel through simulations. For the simulations, we considered a more realistic continuous injection of particles with different magnetic forces and frequencies. Based on the results from our simulation studies, we performed in vivo mice experiments to evaluate the effectiveness of using a functionalized magnetic force to aid magnetic nanoparticles (MNPs) in crossing the blood-brain barrier (BBB). To implement the functionalized magnetic force, we developed an electromagnetic actuator regulated by a programmable direct current (DC) power supply. Our results indicate that a functionalized magnetic field can effectively prevent MNPs from sticking, and also guide them across the BBB. We used 770-nm fluorescent carboxyl MNPs in this study. Following intravenous administration of MNPs into mice, we applied an external magnetic field (EMF) to mediate transport of the MNPs across the BBB and into the brain. Furthermore, we evaluated the differential effects of functionalized magnetic fields (0.25, 0.5, and 1 Hz) and constant magnetic fields on the transport of MNPs across the BBB. Our results showed that a functionalized magnetic field is more effective than a constant magnetic field in the transport and uptake of MNPs across the BBB in mice. Specifically, applying a functionalized magnetic field with a 3 A current and 0.5 Hz frequency mediated the greatest transport and uptake of MNPs across the BBB in mic

Functionalized Magnetic Force Enhances Magnetic Nanoparticle Guidance: From Simulation to Crossing of the Blood-Brain Barrier in vivo

In recent studies, we introduced the concept of functionalized magnetic force as a method to prevent nanoparticles from sticking to vessel walls caused by extensive simulation and in vitro experiments involving a Y-shaped channel. In this study, we further investigated the effectiveness of the functionalized magnetic force with a realistic 3D vessel through simulations. For the simulations, we considered a more realistic continuous injection of particles with different magnetic forces and frequencies. Based on the results from our simulation studies, we performed in vivo mice experiments to evaluate the effectiveness of using a functionalized magnetic force to aid magnetic nanoparticles (MNPs) in crossing the blood-brain barrier (BBB). To implement the functionalized magnetic force, we developed an electromagnetic actuator regulated by a programmable direct current (DC) power supply. Our results indicate that a functionalized magnetic field can effectively prevent MNPs from sticking, and also guide them across the BBB. We used 770-nm fluorescent carboxyl MNPs in this study. Following intravenous administration of MNPs into mice, we applied an external magnetic field (EMF) to mediate transport of the MNPs across the BBB and into the brain. Furthermore, we evaluated the differential effects of functionalized magnetic fields (0.25, 0.5, and 1 Hz) and constant magnetic fields on the transport of MNPs across the BBB. Our results showed that a functionalized magnetic field is more effective than a constant magnetic field in the transport and uptake of MNPs across the BBB in mice. Specifically, applying a functionalized magnetic field with a 3 A current and 0.5 Hz frequency mediated the greatest transport and uptake of MNPs across the BBB in mic

Antibacterial Effect of Persicaria thunbergii on Staphylococcus aureus

With the discovery of various antibiotic resistant bacteria, evaluations of antimicrobial activities of natural compounds have been preceded on antibiotic susceptible and resistant microorganisms. Several types of natural compounds have been reported to have similar effects on target microorganisms as compared to the widely used antibiotics. Persicaria thunbergii (Polygonaceae) has been known to have anti-tumoral, anti-angiogenesis, anti-oxidation and anti-inflammation functions. In this study, aerial parts of P. thunbergii were extracted using methanol, chloroform, and ethyl acetate to identify possible anti-bacterial effects. Agar disk diffusion method and time-kill assay were done to evaluate the antibacterial effect of P. thunbergii extracts. Two extracts ethyl acetate (EAE), and chloroform (CFE) were tested against Staphylococcus aureus. As a result, the extract from CFE and EAE showed antibacterial effect against S. aureus. The extract EAE showed the strongest inhibition effect compared to CFE. These results demonstrate that the EAE extract which originated from P. thunbergii can probably play a role as an antibacterial agent

Self-assembly of hierarchical porous structure for stretchable superhydrophobic films by delicately controlling the surface energy

Herein, thermoplastic polyurethane (TPU) was not only used as the means of attaching modified silica (m-SiO₂), but was also used as a flexible polymer substrate combining with poly(amide–imide) (PAI) for improving the robustness of stretchable superhydrophobic films by self-assembly. m-SiO₂ floated up and TPU sank down in the superhydrophobic coating layer while TPU floated up and PAI sank down in the PAI–TPU stretchable substrate layer by delicately controlling the surface energies of the materials (γPAI > γTPU > γm-SiO₂). With this strategy, the two layers penetrated into each other, and the compatibility between the superhydrophobic coating and polymer substrate was improved due to the same component of TPU, which made m-SiO₂ firmly attach to the stretchable substrate and uniformly disperse into the PAI–TPU substrate. In addition, during the up–down process, a hierarchical porous structure with robust microscale bumps was formed, which offered a stable Cassie state. As expected, the PAI–TPU/m-SiO₂ superhydrophobic film was highly stretchable, and can bear 2000 cycles of stretching–releasing (0% → 30% → 0%) without sacrificing its superhydrophobicity. The tight adhesion between the decorated m-SiO₂ and stretchable substrate rendered outstanding mechanical robustness with resistance to sandpaper abrasion, knife-scuffing, ultrasonic treatment, and hot-water jet impact. The PAI–TPU/m-SiO₂ superhydrophobic surface also showed excellent durability when exposed to acid–base immersing, cooling or heating, and UV irradiation. Furthermore, the PAI–TPU/m-SiO₂ superhydrophobic surface possessed excellent self-healing, and icephobic properties. For practical application, PAI–TPU/m-SiO₂ stretchable superhydrophobic films were applied as water-proof covers for curved surfaces, or served as a self-cleaning coating. These versatile features demonstrated a simple and convenient method to fabricate stretchable superhydrophobic surfaces with multi-functionality