Remote-Controlled DNA Release from Fe3O4@Au Nanoparticles Using an Alternating Electromagnetic Field

We demonstrated a remote-controlled DNA release strategy, in which irradiation of nanoparticles with an alternating electromagnetic field (AMF) results in DNA release on demand. The method we developed used 6-carboxyfluorescein (FAM)-labeled diblock DNA to modify Fe3O4@Au nanoparticles (NPs) through the affinity of adenine with the surfaces of the NPs. The DNA release was confirmed by zeta potential measurement, surface-enhanced Raman scattering spectroscopy, gel electrophoresis, and fluorescence spectroscopy. The experimental results showed that the DNA was released into the surrounding medium under irradiation with an AMF at a frequency of 20-25 kHz. The DNA release was efficient (60%-70%), and externally controllable by tuning various parameters, such as the sequences length of the diblock DNA, the pH value of environmental solutions, and the power and the time of AMF irradiation. Furthermore, the AMF-triggered DNA release was successfully performed in human cervical cancer (HeLa) cells, demonstrating the system's ability to maintain the release behavior in vitro. This remote-controlled DNA release method presents a new application for DNA-modified NPs in targeted therapies.