BEH.462/3. 962J Molecular Principles of Biomaterials Spring 2003 INTERNALIZATION: used to down-regulate signals mobilized cytokines may show more potent signaling due to lack of this down-regulation pathway One of the first examples- Griffith lab work with epidermal growth factor immobilized on star polymers Glass slide Aminate Z.CHCH, OI g. 2 Tethered EGF produces same increase in DNA synthe sis as soluble EGF for primary rat hepatocytes. a, Soluble EGF case contained 10 ng/ml EGF(EGF)or 0 ng/ml EGF (EGF). Tethered EGF 180 and M, r1,000)as shown in 320 3. 2 ng/cm' covalently tethered EGF and 1.9 ng/cm'nonspecifi- ally adsorbed EGF (EGF)or o ng/cm covalently tethered EGF and 1.9 ng/cm nonspecifically ad sorbed EGF (EGF). Staining index represents the number of nuclei stained per area covered by cells, and represent the mean t s.d. for 200)as shown in Fig, 1b; surfaces present either 0. 4 ng/cm covalently tethered EGF and <0.006 ng/cm' nonspecifically adsorbed EGF (EGF)or O ng/cm covalently tethered EGF and <0.006 ng/cm nonspecifically adsorbed EGF(EGF). DNA synthesis was measured as a per. tage of the total nuclei that had synthesized DNA and each point represents the mean s d. for three separate surfaces with at least Lecture 4- Biological Recognition pt. 2 7 of 9BEH.462/3.962J Molecular Principles of Biomaterials Spring 2003 • INTERNALIZATION: used to down-regulate signals ƒ Immobilized cytokines may show more potent signaling due to lack of this down-regulation pathway • One of the first examples- Griffith lab work with epidermal growth factor immobilized on star polymers: Lecture 4 – Biological Recognition pt. 2 7 of 9