Successful genetic modification of porcine spermatogonial stem cells via an electrically responsive Au nanowire injector.

Transgenic pigs are quite useful in many biomedical fields, such as xenotransplantation research and the production of biopharmaceutical materials. The genetic transformation of porcine spermatogonial stem cells (pSSCs) followed by differentiation into mature spermatozoa enables the effective production of transgenic pigs. Improving the transfection efficiency of pSSCs, however, has been much desired. Herein, we report the efficient genetic modification of pSSCs by using an electrically responsive Au nanowire injector (E-R Au NWI). This is the first study that shows an exogenous gene is directly delivered into the nucleus of a pSSC by using a 1-dimensional nanomaterial and then successfully expressed to produce a protein. The E-R Au NWI interfaced noninvasively with the nucleus of the pSSC, and the pEGFP-N1 plasmid was delivered by the application of an electrical stimulus without cell damage. Compared to the results of conventional nonviral vector-based gene delivery methods such as jetPEI, Lipofectamine, and electroporation, the E-R Au NWI-based method improved the pSSC transfection efficiency by at least 6.7-fold and even up to 46.7-fold. Furthermore, we successfully obtained transgenic pSSCs containing the human bone morphogenetic protein 2 gene by using E-R Au NWIs. This result suggests that the E-R Au NWI enables the efficient genetic modification of pSSCs and can be employed to produce diverse kinds of transgenic pigs.