Rf 5301 fluorometer

Intracellular reactive oxygen species in yeast cultures were determined using fluorescence assays with 2′,7′-dichlorodihydrofluorescein diacetate.⁸ (link) The cultured cells obtained from a pre-culture were incubated for 2 h at 40 °C, cells were counted and diluted in YPD medium to a final concentration of 0.5 × 10⁷ cells. A 5-mM stock solution of dichlorofluorescein diacetate was added to each sample and incubated in the dark for 15 min at 30 °C. Afterwards, cells were harvested by centrifugation, washed, and re-suspended in 1930 μL 50 mM Tris/HCl buffer (pH 7.5). The cells were permeabilized by adding chloroform and SDS and vortexing at high speed for 20 s. The tubes were left to settle for 10 min. Cells were pelleted by centrifugation, and the supernatant fluorescence was measured using a Shimadzu RF-5301 fluorometer (excitation, 502; emission, 521 λ).

The fluorescence of water-soluble PEI-AgNCs was analyzed using RF-5301 fluorometer (Shimadzu, Kyoto, Japan). The color of water-soluble PEI-AgNCs was measured under visible and ultraviolet (UV) light. The shape and size of the PEI-AgNCs were measured by transmission electron microscopy (TEM, JEM-100SX microscope; JEOL, Tokyo, Japan). The aqueous solution of PEI-AgNCs was dropped into the copper net. TEM observation was carried out after the samples were air-dried at room temperature.