Reaction oxygen species (ROS) measurement
The ROS production capacity of
cells cultured under both 2D monolayer and 3D MTSs was determined using
the ROS detection kit (50101ES01,
Yeasen, Shanghai, CN), according to the manufacturer’s protocol. The
fluorescence dye DCFH-DA (2, 7-Dichlorodi-hydrofluorescein diacetate),
without its own fluorescence, could freely shuttle through the cell
membrane, and is hydrolyzed by intracellular esterase to generate DCFH,
which could not shuttle through the cell membrane, and accumulates in
cells. Non-fluorescent DCFH could be oxidized by intracellular ROS to
produce DCF with green fluorescence. The fluorescence intensity was
measured by fluorescence microplate reader (Thermo Fisher Scientific,
Waltham, MA, USA) at the excitation wavelength of 488 nm and the
emission wavelength of 525 nm.