Spatial control of in vivo CRISPR-Cas9 genome editing via nanomagnets.

The potential of clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated protein 9 (Cas9)-based therapeutic genome editing is hampered by difficulties in the control of the in vivo activity of CRISPR-Cas9. To minimize any genotoxicity， precise activation of CRISPR-Cas9 in the target tissue is desirable. Here， we show that， by complexing magnetic nanoparticles with recombinant baculoviral vectors (MNP-BVs)， CRISPR-Cas9-mediated genome editing can be activated locally in vivo via a magnetic field. The baculoviral vector was chosen for in vivo gene delivery because of its large loading capacity and ability to locally overcome systemic inactivation by the complement system. We demonstrate that a locally applied magnetic field can enhance the cellular entry of MNP-BVs， thereby avoiding baculoviral vector inactivation and causing a transient transgene expression in the target tissue. Because baculoviral vectors are inactivated elsewhere， gene delivery and in vivo genome editing via MNP-BVs are tissue specific.