90plus bi mas

A Brookhaven Instruments 90Plus/BI-MAS dynamic light scattering and zeta potential measurement instrument, operating at a scattering angle of 90° at room temperature, was used to determine the hydrodynamic size and zeta potential of the SPIONs. For hydrodynamic diameter measurements, particles were suspended at 1 mg/mL in deionized water. The zeta potential of the particles was measured in a 1 mM KNO₃ solution at pH 7, adjusted with nitric acid and potassium hydroxide.

The nanoparticle was characterized using both transmission electron microscopy (TEM) and dynamic light scattering (DLS). First, nanoparticles were soaking in soaking in Phosphate Buffer (pH 7.4, pH 6.0) or Acetate Buffer (pH 5.0), respectively, for 6 h. For TEM study, the nanoparticles were negatively stained with uranyl acetate solution (2%, w/w) and examined using an FEI (Moorestown, NJ, USA) Tecnai G2 Spirit transmission electron microscope. The nanoparticle size was determined using a Brookhaven (Holtsville, NY, USA) 90 Plus/BI-MAS dynamic light scattering instrument.

The sample morphology was characterized by a transmission electron microscopy (TEM, FEI Tecnai G2 Spirit, Holland). The morphology and size of sample were characterized by atomic force microscopy (AFM, Dimension ICON, Bruker, USA). X-ray photoelectron spectra (XPS) were acquired by using SSI S-Probe XPS spectrometer with Al Kα radiation as an X-ray source (1486 eV). The hydrodynamic size was measured by dynamic light scattering (DLS, 90Plus/BI-MAS instrument, Brookhaven Instruments Co., USA). The Fourier transform infrared (FT-IR) spectra were characterized by infrared spectrometer (L16000300 Spectrum TWO LITA, Llantrisant, UK) between 4000 and 500 cm^-l through a potassium bromide (KBr) pellet method. Thermogravimetric analysis (TGA) was performed using a Discovery TGA 50 (USA) instrument by scanning from 25 to 600 °C under oxygen at a heating rate of 10 °C/min. The UV-Vis absorption spectra were recorded by a UV-Vis-NIR spectrophotometer (Cary 60, Agilent Technologies, USA). The concentration of Au was measured using a Thermo inductively coupled plasma mass spectrometry (ICP-MS) XSERIES 2. Samples for ICP-MS analysis were prepared by dissolving Au NCs-NAC in aqua regia for overnight and diluted with ultrapure water. The in vitro ROS detection was performed by confocal laser microscopy (LSM880, Carl Zeiss, Göttingen, Germany).

All phospholipids including 18 mg 1,2‐dihexadecanoyl‐rac‐glycero‐3‐phosphocholine (DPPC), 3.5 mg distearoyl phosphatidyl ethanolamine polyethylene glycol 2000 (DSPE‐PEG2000), 1 mg diphenyl phosphoryl azide (DPPA) and 2 mg Sildenafil (HY‐15025, MCE) were dissolved in 4 mL chloroform in a round‐bottom flask. Afterwards, the solution was evaporated at 60°C for about 0.5 h to form a phospholipid structure. Maintaining at 60°C for 0.5 h, the phospholipid film was then hydrated using 4 mL phosphate‐buffered saline (PBS) to form Sildenafil‐loaded liposomes. Then, 0.5 mL Sildenafil‐loaded liposomes suspensions were put in a 1.5‐mL centrifuge tube and purged with different proportions of NO (0%, 20%, 40%, 60%, 80%, and 100%) and perfluoropropane (C3F8) gas mixture continuously to replace the air inside. The admixture was then mechanically vibrated for 45 s at 70 Hz using a dental amalgamator (YG‐10, ZOGEAR, China) to obtain final different types of Sil‐NO‐MBs. The diameters of the MBs were detected using the dynamic light scattering (DLS) method (90 Plus/BI‐MAS, Brookhaven Instruments, USA).