Efficient DNA release from PAMAM dendrimer-modified superparamagnetic nanoparticles for DNA recovery

DNA recovery using solid-phase extraction is a fundamental technique in molecular biology and biotechnology. Our research group developed a novel DNA recovery method using amine-modified magnetic nanoparticles (MNPs) as a solid support. The use of MNPs simplifies the DNA recovery processes and permits their use in automated systems. In this study, we prepared polyamidoamine-modified superparamagnetic particles (PAMAM-SpMNPs) with 10-nm magnetite cores and used them for DNA recovery. To improve the DNA-release efficiency, the surface amine numbers on the particles were evaluated to modify each generation of PAMAM. With this optimization, the PAMAM-SpMNPs maintained a high DNA adsorption capacity and high dispersivity in solution. As a result, the DNA release from the PAMAM-SpMNPs of every generation was highly efficient. In particular, the release of DNA from the G4 to G6 PAMAM-SpMNPs was greater than 95%. Furthermore, an alternating magnetic field (AMF) was applied to expedite the DNA release from the PAMAM-SpMNPs. Complete DNA release was achieved using AMF treatment for 10 min. The DNA recovery method using the PAMAM-SpMNPs will permit various types of testing using DNA from a low volume sample, such as in a micro total analytical system.