Amplified fluorescence polymers (AFP) are a set of unique polymers known for their ability to detect trace nitro explosives. The prior knowledge in the AFP field indicates that the functional group variation on the polymer backbone is responsible for the selectivity of an analyte. The mechanism of analyte detection is believed that only compounds with nitro functional groups are detected by AFP. Usually, AFP functional groups varied to detect nitro compounds and the non-nitro compound detection and the mechanism of the AFP were not completely understood. In this work, the AFP polymer was kept constant and studied with 136 analytes with different functional groups for analyzing few non-nitro compounds. Among the 136 compounds analyzed, about fourteen have been detected by AFP. It was observed that most of the fourteen compounds were non-nitro compounds. The mechanism proposed originally for nitro compounds and associated hypothesises the existence of a parking space on the polymer backbone. Present study suggested that the possibility of only nitro compounds interacting with AFP due to the three-dimensional shape of the analyte as the detrimental factor. The discovery of non-nitro compound detection by AFP opens up the use of AFP for gas-phase disease volatile organic compound detection. Future studies of functional group variation on the AFP backbone in relation to the analyte detection could provide insights into the relation of analyte detection by AFP and the parameters to optimize for obtaining the selectivity and specificity.

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The DNA-binding mode of N,N'-Dibenzylidene-9H-Carbazole-3,6-Diamine with CT-DNA was investigated by absorption spectroscopy, EB-DNA displacement, circular dichroism, thermal denaturation and viscosity measurements. Results indicated that these compounds intercalate into the base pairs of CT-DNA. The effect of ionic strength on the fluorescence property of the system indicated the presence of electrostatic interaction via phosphate backbone of DNA helix. The intrinsic binding constant values suggested that compound has DNA binding propensity. This compound promote the cleavage of plasmid pBR322. These results may be useful for the design of N,N'-Dibenzylidene-9H-Carbazole-3,6-Diamine with desired binding characteristics and useful to better understand the DNA binding mode of heterocyclic compound.

The DNA-binding mode of 9-Phenyl carbazole with CT-DNA was investigated by absorption spectroscopy, EB-DNA displacement, circular dichroism, thermal denaturation and viscosity measurements. Results indicated that these compounds intercalate into the base pairs of CT-DNA. The effect of ionic strength on the fluorescence property of the system indicated the presence of electrostatic interaction via phosphate backbone of DNA helix. The intrinsic binding constant values suggested that compound has DNA binding propensity. This compound promote the cleavage of plasmid pBR322. These results may be useful for the design of 9-Phenyl carbazole with desired binding characteristics and useful to better understand the DNA binding mode of heterocyclic compound.