Methods to promote Notch signaling at the biomaterial interface and evaluation in a rafted organ culture model

The Notch signaling pathway is a promising target for controlling cell fate choices at the biomaterial‐tissue interface. Building on our previous work in developing Notch‐signaling biomaterials, we evaluated various immobilization schemes for Notch ligands, and their effect on human foreskin keratinocytes. A peptide sequence derived from the Jagged‐1 DSL‐region and immobilized to poly(2‐hydroxyethyl methacrylate) (polyHEMA) showed no bioactivity in relation to the Notch‐CSL pathway. The full‐length Jagged‐1 protein immobilized directly to the polyHEMA surface showed activity in signaling the Notch‐CSL pathway. However, an indirect affinity immobilization approach yielded a stronger signal. Human keratinocytes plated on bound Jagged‐1 showed upregulated involucrin, keratin 10, and loricrin protein expression, with this expression being cell density‐dependent. Utilizing a human foreskin rafted organ culture model as a bridge between in vitro and in vivo studies, Jagged‐1‐modified or control polyHEMA rods were implanted in human foreskin and cultured at the air‐medium interface. Keratinocyte proliferation was suppressed and intermediate‐stage differentiation promoted in Jagged‐1‐modified rods compared with control rods. Thus, Notch‐signaling biomaterials provide a robust approach to control keratinocyte differentiation and may find application to other progenitor and stem cells. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res 2009