Highly efficient adsorption of DNA on Fe3+–iminodiacetic acid modified silica particles

In this work, the adsorption of DNA on Fe3+ immobilized silica particles under different pH and salt concentration was investigated. At pH lower than 4.0, DNA was adsorbed efficiently (>90%) on the particles surface driven by the coordination interaction between the Fe3+ ions and phosphate groups of DNA, which was almost not affected by the salt concentration in the solution. At pH higher than 5.0, the adsorption of DNA became sensitive to the salt concentration, and high efficient adsorption (∼90%) of DNA could be acquired under high salt concentration driven by the salt bridge. The DNA molecules adsorbed on the particle surface via the coordination could be released completely under elevated pH. Compared to pure silica particles, such Fe3+ immobilized silica particles are qualified for the high efficient extraction of DNA based on either the coordination interaction or the salt bridge.