Method to inject genes into cells
Remember, phages infect bacteria. It looks like he used something called pMXs-based retroviral vectors instead, which is based on the Moloney murine leukemia virus (MMLV).

I have never heard of that virus before, but I do know of others used in vivo to deliver genes, including Lentivirus, Adenovirus, and Adeno-associated virus. All have their strengths and weaknesses. Adenovirus is large so you can fit a big gene inside it, but it tends to illicit a high immune response. AAV, on the other hand, is very small but has a much more mild immune response. It can fit a gene about 4kb long inside or half that if you use a fast expressing form called self-complementary AAV. What is nice about AAV is one of the subtypes (technically callled serotype) can cross the blood brain barrier, so it has already been used in clinical trials to try and treat neurological diseases, including Parkinson’s.