Polymeric biomaterials are one of the cornerstones of tissue engineering. A wide range of materials has been used. Approaches have shown increasing sophistication over recent years employing drug delivery functionality, micropatterning, microfluidics, and other technologies. Challenges such as producing three-dimensional matrixes and rendering them deliverable through minimally invasive techniques have been addressed. A major recent development is the design of biomaterials for tissue engineering matrices to achieve specific biologic effects on cells, and vice versa. Much remains to be achieved, particularly in integrating other new technologies into the field.