What are scaffolds? Tissue engineering often requires a "scaffold" on which to grow living tissue, otherwise, we assume, you'd end up with misshapen blobs of living goo. The scaffolds represent the desired final shape into which tissue will be grown. The living tissue is deposited on the scaffold, and natural reproduction takes over from there. One more thing to complete the picture: the scaffolds are made from bio-degradable material. After they dissolve only the living tissue remains in the desired shape.
The 3D-Bioplotter is really a species of 3D printer that uses specific materials. It has other characteristics such as being able to work in a sterile manner, and print heads that can operate in different temperature ranges.