Fig. 3 | Nature Communications

Fig. 3

From: Molecular demultiplexer as a terminator automaton

Fig. 3

Operation of the molecular automata as evidenced by spectroscopic and cell culture data. a MTT assay data: Green open circles correspond to percent death of K562 cells under irradiation at 522 nm for 12 h followed by continued incubation in dark for another 12 h. Solid black circles correspond to cells kept under identical conditions of incubation with the agent, but in dark. Positive control (dashes at 100% line) corresponds to cells incubated in DMSO-growth medium mixture (50/50, v/v). b The truth table with the data and switch inputs, and the corresponding outputs clearly identified, and the particular set of conditions valid under the light irradiation conditions on power-up were highlighted. c Switch input 0 (no added phosphate in the model system or lack of phosphatidylserine (PS) in the external leaflet of the cell membrane in the cell cultures) selects singlet oxygen as the primary output. d The model compound T-2, which is the Zn2+ complex of the meso-terpyridyl-bodipy compound, has a very low fluorescence emission intensity in acetonitrile. e The addition of phosphate ions results in a very sharp increase in emission intensity. The low emission intensity is due to the availability of a charge transfer state (CTS) resulting in enhanced intersystem crossing, which in turn leads to efficient generation of singlet oxygen. f The decrease in the absorbance at 411 nm, in an oxygen saturated ethanol solution of selective singlet oxygen trap DPBF (50 µM) in the presence of 2.0 µM T-2 and under irradiation with 522 nm green LED light source (solid blue squares). The singlet oxygen quantum yield (ϕΔ) of T-2 is 0.11. The addition of phosphate (red open circles) destabilizes the CTS state, blocking access to the triplet manifold. The absorbance data presented is the net absorbance values obtained by subtracting any background decrease in the probe absorbance due to light alone

Back to article page