Progress in three-dimensional printing with growth factors.

Incorporation of growth factors in biomedical constructs can encourage cellular activities necessary for tissue regeneration within an implant system. Three-dimensional printing offers a capacity for spatial dictation and dosage control of incorporated growth factors which promises to minimize complications from the supraphysiologic doses and burst release involved in current growth factor delivery systems. Successful implementation of three-dimensional printing with growth factors requires preservation of the bioactivity of printed growth factors, spatial localization of growth factors within the construct architecture during printing, and controlled release of growth factors after printing. This review describes demonstrated approaches for addressing each of these goals, including direct inclusion of growth factors with the biomaterial during printing, or intermediary encapsulation of growth factors in delivery vehicles such as microparticles or nanoparticles.