Fig. 2.

a Gel electrophoresis showed that the TDN remained stable for 24 h in complete medium at 37 °C (A); the TDN remained stable for 7 h when the concentration of foetal bovine serum was increased to 50% (B). b U87MG cells were co-cultured with the TDN at different concentrations (10–500 nM) for 24 h and 48 h. The CCK-8 assay showed that the activity of the U87MG cells was not affected, which indicated the biosafety of the TDN