Manganese dioxide nanosheet-containing reactors as antioxidant support for neuroblastoma cells.

Supporting mammalian cells against reactive oxygen species such as hydrogen peroxide (H 2 O 2 ) is essential. Bottom-up synthetic biology aims to integrate designed artificial units with mammalian cells. Here, we used manganese dioxide nanosheets (MnO 2 -NSs) as catalytically active entities that have superoxide dismutase-like and catalase-like activities. The integration of these MnO 2 -NSs into 7 μm reactors was able to assist SH-SY5Y neuroblastoma cells when stressed with H 2 O 2 . Complementary, Janus-shaped 800 nm reactors with one hemisphere coated with MnO 2 -NSs showed directed locomotion in cell media with top speeds up to 50 μm s -1 when exposed to 300 mM H 2 O 2 as a fuel, while reactors homogeneously coated with MnO 2 -NSs were not able to outperform Brownian motion. These Janus-shaped reactors were able to remove H 2 O 2 from the media, protecting cells cultured in the proximity. This effort advanced the use of bottom-up synthetic biology concepts in neuroscience.