Fig. 7: Dual labeling in living cells based on mutual orthogonality between sydnthione‒DIBAC and tetrazine‒Nor bioorthogonal cycloaddition pairs.

a Mutual orthogonality between sydnthione‒DIBAC and tetrazine‒Nor bioorthogonal cycloaddition pairs. F: BODIPY. b Dual labeling of living cells. I: HeLa cells were incubated with 1f (30 μM) and DCI-CHO-DNP (10 μM) for 3.5 h at 37 °C. II: HeLa cells were incubated with Tz-504 (30 μM) and DCI-CHO-DNP (10 μM) for 30 min, and then treated with DIBAC (300 μM) for 3 h at 37 °C. III-V: HeLa cells were incubated with 1f (30 μM) and DCI-CHO-DNP (10 μM) for 30 min, then treated with either DIBAC (300 μM, III) or Tz-504 (30 μM, IV) or both (V) for 3 h at 37 °C. Scale bar = 10 μm. The experiment was independently repeated three times with similar results.