ABSTRACT
In tissue engineering, controlled delivery encompasses “the provision of a bioactive molecule over time in a manner such that its biological activity can be productively harnessed” (Hubbell 2008). e use of controlled drug delivery, more so than the other goals of drug delivery, has come into greater use in tissue engineering in recent years (Biondi et al. 2008, Fisher et al. 2010, Uebersax et al. 2009). In this context, there are three major applications of drug delivery concepts that are being widely used to engineer tissue constructs: (a) spatially and temporally controlled delivery of proteins, peptides, lipids, and small molecules (e.g., growth factors, enzymes, and morphogens), (b) spatially patterned presentation of cell-signaling ligands, and (c) delivery of nucleic acids to direct progenitor cells to specic pathways (e.g., through either ectopic gene expression or targeted gene silencing).
