Telomere loss

Most cells have a length of DNA called the "telomere" that gets shorter each time they divide. After a certain number of divisions, the telomere is gone, and they die. (This is probably an anti-cancer mechanism.) If life is to be extended, cells will need to have their telomeres replaced so that they can keep working. We know that cancer cells have managed to avoid the telomere trap, and we already know of an enzyme that performs this function. It should be simple to induce a cell to lengthen its telomeres, using a machine built on the same scale as the cell that can sense its state and dispense the right chemicals at the right time.