Fig. 4. Interference-resistant two-photon fluorescence imaging of the COF nanoprobe TpASH-NPHS in deep tumor tissues. (A) Two-photon confocal fluorescence images of TpASH-NPHS and CNPHS under hypoxia in HepG2 tumor tissues without or with the addition of exogenous H2S. Scale bar: 300 μm. (B) The relative pixel fluorescence intensity of HepG2 tumor tissues. The pixel signal intensity from TpASH-NPHS incubated with H2S in HepG2 tumor tissues under normoxic conditions is defined as 1.0.
