Abstract
Limited number of potential tracers such as salts, isotopes and dyes, make study of hydrological processes a challenge. Traditional tracers find limited use due to lack of multipoint tracing and background noise, among others. DNA based tracers have been shown to have great potential enabling synthesis of ideally unlimited number of unique tracers besides being environmentally friendly, highly sensitive and capable of multipoint tracing. To prevent unintentional losses in the environment during application and easy recovery for analysis, we hereby report DNA encapsulation in silica containing magnetic cores (iron oxide) of two different shapes – spheres and cubes, in the size range 10-20 nm, synthesized using co-precipitation or thermal decomposition. Physico-chemical properties such as size, zeta potential, etc of the iron oxide nanoparticles have been optimized for different ligands and surfactants. We report for the first time the effect of surface coating on the magnetic properties of the iron oxide nanoparticles at each stage of functionalization, culminating in silica shells. Efficiency of encapsulation of three different dsDNA molecules has been studied using quantitative polymerase chain reaction (qPCR). Our results show that our DNA based magnetic tracers can be used for hydrological monitoring with easy recoverability and high signal amplification.
Dopamine coated Fe3O4 nanoparticles as enzyme mimics for the sensitive detection of bacteria
