4-D printing is taking conventional 3-D printing and adding a time factor into the process. Certain materials that are compatible with biological systems expand, contract, bend, or straighten into calculated shapes when introduced to an external energy st

4-D printing is taking conventional 3-D printing and adding a time factor into the process. Certain materials that are compatible with biological systems expand, contract, bend, or straighten into calculated shapes when introduced to an external energy st