Achieving controlled cell adhesion in practice: 1 method o Incorporation of poly(ethylene glycol) at surface with adhesion peptides Creating a blank slat (SLIDE PMMA M=20K G100K a/mol comb 里 2) now add adhesion peptides:(Here, Arg-Gly-Asp-based peptide) TCPS Unmodified Pla Tethered rgd concept of soluble peptide control: integrin-mediated attachment is low-affinity but high avidity: many receptors binding on and off relatively quickly Lecture 3- Biological Recognition 10 of 15• Achieving controlled cell adhesion in practice: 1 method o Incorporation of poly(ethylene glycol) at surface with adhesion peptides Creating a ‘blank slate’:11-14 (SLIDE) PMMA O O OH O O O O O x y z Fraction of cells adhered relative to TCPS O O O O OH n ~ 6 O O O OH + O O O n ~ 6 (1)(1) m O n M = 20K Ğ100K g/mol O OH 0.2 9-unit side chains comb (1) + O N O O n ~ 6 O O O O N 0.15 O (2) 0.1 O O O O O O O O n ~ 6 (3) N GRGDSP OH 0.05 (2) + H2N GRGDSP OH H 0 20 30 45 weight fraction PEO units now add adhesion peptides: (Here, Arg-Gly-Asp-based peptide) TCPS 0.5 0.4 Unmodified PLA 0.3 0.2 0.1 0 GRGDSP GRGESP Fraction seeded cells adhered Fraction Seeded Cells Adhered + soluble RGD Tethered RGD ƒ concept of soluble peptide control: integrin-mediated attachment is low-affinity but high avidity: many receptors binding on and off relatively quickly Lecture 3 – Biological Recognition 10 of 15