New approaches to treat diseases: In vivo (In the living animal) gene editing in monkeys reduces a liver protein, lowering cholesterol levels to improve cardiac health. About 60% of the cells in the liver were effected, an impressive percentage. Science mag news article here. Mitochondrial transplant to damaged infant heart tissue. Mitochondrial can get damaged and/or killed, leaving the cells alive but not very functional (not good for heart cells). Undamaged mitochondrial from OK parts of the injured party's body (eliminating the possibility of immune rejection) are isolated and injected in to a mass of injured cardiac muscle cells. The mitochondria (a cellular organelle, much larger than a molecule, more like a bacteria, with their own mini-genome) get into the cells (by means unknown to me,) and provide the cell with much more functional energy sources than the damaged mitocondria. Cells get better, improving heart output. This also requires effecting a decent percentage of the target cells (thousands to millions), in a tissue (lots of structure and diffusion barriers (especially for large particles)). NY Times article here.