Researchers can build artificial cell components, and are well on the way to artificial cells, so why not artificial viruses as well? "Natural viruses are extremely effective at transporting genes into cells for gene therapy; their disadvantage is that they can initiate an immune response or cause cancer. Artificial viruses do not have these side effects, but are not especially effective because their size and shape are very difficult to control - but crucial to their effectiveness. A research team [has] now developed a new strategy that allows the artificial viruses to maintain a defined form and size. ... Glucose building blocks on the surfaces of the artificial viruses should improve binding of the artificial virus to the glucose transporters on the surfaces of the target cells. These transporters are present in nearly all mammalian cells. Tumor cells have an especially large number of these transporters. Trials with a line of human cancer cells demonstrated that the artificial viruses very effectively transport an siRNA and block the target gene. ... researchers were able to attach hydrophobic (water repellant) molecules - for demonstration purposes a dye - to the artificial viruses. The dye was transported into the nuclei of tumor cells." A nice technology demonstration, and the wave of the future in making gene therapy more effective, no doubt: we can take from the mechanisms we find in nature, and then improve on them.