A simple and efficient intracellular delivery method induced by a magnetic rod

In cell-based biomedical applications, intracellular delivery is an important technique for gene modification and drug delivery. Various delivery methods have been proposed to overcome the cell plasma membrane barrier in the delivery of DNA, mRNA, and drugs. Current methods, such as lipofection and viral method, cannot effectively deliver materials in some cell types (e.g., cells with abundant extracellular matrix (ECM). Moreover, physical methods, such as electroporation, result in low cell viability after delivery. Recent development has shown that a transient hole on the cell plasma membrane, created through mechanical deformation, can allow delivery of macromolecules into a cell. Inspired by this finding, we developed a magnetic glass rod for the high-throughput and efficient delivery of materials into cells. To transfer materials into cells, the magnetic glass rod exerts compression and shear force on top of the cell by applying an external magnetic field with a magnet. The applied force can be controlled by changing the distance between the magnetic glass rod and the magnet. This simple method can efficiently deliver plasmid DNA or tetramethylrhodamine isothiocyanate-dextran into cells. Fabrication of such a magnetic glass rod only requires a glass capillary, an iron rod, and polydimethylsiloxane. This efficient approach is much simpler than the current method used for intracellular delivery.