Studies on Adsorption of DNA on Functional Ultrathin Films of Cationic Surfactant

We have investigated the interaction of DNA with a highly ordered functional ultrathin layer of cationic surfactant, dioctadecyl ammonium bromide (DOAB). The ultrathin film of DOAB is fabricated by Langmuir-Blodgett technique onto the pretreated quartz crystal wafers. The solution of DNA in phosphate buffer saline (PBS) is injected through a flow cell in a quartz crystal microbalance (QCM) loaded with the functional ultrathin film. The QCM data indicate a slower kinetics (time constant  =  162.2 seconds) for the adsorption of DNA on DOAB layer as compared to PBS on DOAB. The surface morphology of the aggregation of DNA over the DOAB layer is investigated using atomic force microscope (AFM). The AFM image indicates the trapping of DNA over the DOAB layer. Such trapping of DNA can be potentially employed in the field of genomics.