Fig. 5. The signal changes of 3IAN4 (3.0 μM) as a molecular logic gate for COX-2 and NAT in HepG2 cells. Blue channel: excitation wavelength = 405 nm, scan range = 450–500 nm. Green channel: excitation wavelength = 488 nm, scan range = 500–550 nm. (a-3), (b-3), (c-3) and (d-3) were the activity of COX-2 and NAT in groups (a–d), which were obtained by ELISA. The cells in (b) group were untreated; the cells in (a) group were treated by nimesulide (10 mM); the cells in (c) group were treated by celecoxib (100 μM). The cells in (d) group were treated by celecoxib (10 mM). The incubation time of celecoxib (10 mM and 100 μM) and nimesulide (10 mM) are 2–6 h, respectively. The appropriate incubation times of celecoxib and nimesulide were ensured by measuring the activities of NAT and COX-2 in every sample as detected by an ELISA assay. Scale: 20 μm.