Magnetic Helical Microswimmers Functionalized with Lipoplexes for Targeted Gene Delivery

Artificial micro-/nanoswimmers have various potential applications including minimally invasive diagnosis and targeted therapies, environmental sensing and monitoring, cell manipulation and analysis, and lab-on-a-chip devices. Inspired by natural motile bacteria such as E. Coli, artificial bacterial flagella (ABFs) are one kind of magnetic helical microswimmers. ABFs can perform 3D navigation in a controllable fashion with micrometer precision under low-strength rotating magnetic fields (<10 mT) and are promising tools for targeted drug delivery in vitro and in vivo. In this work, the successful wirelessly targeted and single-cell gene delivery to human embryonic kidney (HEK 293) cells using ABFs loaded with plasmid DNA (pDNA) in vitro is demonstrated for the first time. The ABFs are functionalized with lipoplexes containing pDNA to generate functionalized ABFs (f-ABFs). The f-ABFs are steered wirelessly by low-strength rotating magnetic fields and deliver the loaded pDNA into targeted cells. The cells targeted by f-ABFs are successfully transfected by the transported pDNA and expressed the encoding protein. These f-ABFs may also be useful for in vivo gene delivery and other applications such as sensors, actuators, cell biology, and lab-on-a-chip environments.