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. Polymer Journal (2012) 44, 672–677; doi:10.1038/pj.2012.32; published online 4 April 2012