Em 2010 microscope

Transmission electron microscopy (TEM) and high-resolution TEM (HR-TEM) images were acquired using a JEOL EM-2010 microscope (JEOL, Tokyo, Japan) at an accelerating voltage of 200 kV. The powder X-ray diffraction (XRD) pattern was obtained by a Rigaku D/Max-3C diffractometer (Cu Kα radiation, λ = 0.15418 nm, Rigaku Co. Ltd., Tokyo, Japan). The UV-Vis absorption spectra were acquired by a Jasco V-570-type spectrophotometer (Jasco SLM-468, Tokyo, Japan). Elemental analysis was performed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES) using an ICPS-7500 spectrometer (Shimadzu, Kyoto, Japan). The MTT cell proliferation assay was performed by an ELx808TM absorbance microplate reader (Biotek Instruments Inc., Winooski, VT, USA).

MnO₂-NPs were prepared according to the protocols of a previous report, with a slight modification [13 (link)]. Briefly, 18 mL of KMnO₄ solution (3.5 mg/mL) was mixed with 2 mL of PAH solution (37.4 mg/mL). The mixture was vigorously stirred until the color of the solution changed to brown. MnO₂-NPs coated with PAH were purified using a centrifugal filter (Amicon Ultra-15, MWCO 100 kDa; Millipore). The separated nanoparticles were dispersed in 15 mL of distilled water. The concentration of Mn²⁺ in the solution was determined using an inductively coupled plasma atomic emission spectrometer (ICPS-8100; Shimadzu, Kyoto, Japan). To prepare the Fuco-MnO₂-NPs, fucoidan was added to the MnO₂-NP solution to produce a mass ratio of Mn²⁺ to fucoidan of 1:2, and the solution was stirred for 3 h. The morphology of the nanoparticles was observed by TEM using an EM-2010 microscope (JEOL, Tokyo, Japan) at 200 kV. The absorption spectra of KMnO₄ and MnO₂-NP were obtained using a UV-Vis spectrophotometer (UV-2600; Shimidazu). The hydrodynamic size and zeta-potential of the nanoparticles were measured by dynamic light scattering (Zetasizer ZS90; Malvern, Worcestershire, UK).

All TEM images were obtained using a JEOL EM-2010 microscope at an acceleration voltage of 200 kV. The samples for TEM studies were prepared by drying a drop of the suspension of the nanoparticles on a piece of the carbon-coated copper grid under ambient conditions. The X-ray diffraction pattern was taken by a Rigaku D/Max-2500 diffractometer system. The particle size was estimated by measuring the sizes of 200 particles from TEM images. Elemental analysis was performed by using inductively coupled plasma atomic emission spectroscopy (ICP-AES, Shimadzu, Japan). Magnetization measurements were performed on a Quantum Design MPMS 5XL SQUID magnetometer. MR imaging of the phantoms was performed under a standard head coil and by using a 1.5 T MR imager (Signa Excite; GE Medical Systems, Milwaukee, WI) to obtain the T₂-axial images. The nitrogen adsorption and desorption isotherms were measured at 77 K using a Micromeritics ASAP 2000 Gas Adsorption Analyzer. Total surface areas and pore volumes were determined using the BET (Brunauer-Emmett-Teller) equation and the single point method, respectively.