Biomaterials have been used extensively in medical, personal care, and food applications, with many similar polymers being used across disciplines. This Perspective will emphasize polymers used in medicine and specifically those designed as scaffolds for use in tissue engineering and regenerative medicine. The areas of active research in tissue engineering include: biomaterials design-incorporation of the appropriate chemical, physical, and mechanical/structural properties to guide cell and tissue organization; cell/scaffold integration-inclusion into the biomaterial scaffold of either cells for transplantation or biomolecules to attract cells, including stein cells, from the host to promote integration with the tissue after implantation; and biomolecule delivery-inclusion of growth factors and/or small molecules or peptides that promote cell survival and tissue regeneration. While a significant and growing area of regenerative medicine involves the stimulation of endogenous Stein Cells, this Perspective will emphasize polymer scaffolds used for delivery of cells and biomolecules. The challenges and solutions pursued in designing polymeric biomaterial scaffolds with the appropriate 3-dimensional structure will be explored.