Micellization, anti-proliferative activity and binding study of cationic gemini surfactants with calf thymus DNA

Aggregation behaviour of two cation gemini surfactants i.e., 1,3-bis (1-decylbenzimidazolium) propane bromide BG10 and 1,3-bis (1-octylbenzimidazolium) propane bromide BG8 was studied using conductivity and dynamic light scattering (DLS). The enthalpy (Delta H-m degrees), entropy (Delta S-m degrees) and Gibbs free energy of micellization (Delta G(m)degrees) have been observed from the conductivity method at various temperatures. The anti-proliferative potential of these novel gemini surfactants against human non-small lung cancer cell line-H1299 has been investigated. Both gemini surfactants, BG8 and BG10 showed a considerable inhibition in cancer cell proliferation and IC50 values are observed to reduce with chain length. The ctDNA binding was also observed by UV-visible, transmission electron microscopy (TEM), ethidium bromide (EtBr) exclusion experiments, agarose gel electrophoresis, circular dichroism (CD) and viscometry techniques. These results were further validated by in-silico studies. The binding capability of BG surfactants to ctDNA can be observed from their ability to remove EtBr from the intercalating complex of DNA resulting in fluorescence quenching.