$NVLX encapsulation differs from that done by others in that the capsules that enclose the cells are made primarily of cellulose whereas others use substances such as alginate (a seaweed derivative), agarose, or chitosan, to name three. Because of this, the capsules are very robust and can withstand various external forces and this allows them to be implanted using needles or catheters without damage. Also, because they are made principally of cellulose, the capsules are essentially bio-inert in humans, so they do not degrade even after being present in the body for over two years.