title: Biodegradable copolymers carrying cell-adhesion peptide sequences.
abstract: Amphiphilic block copolymers are used to create bioactive surfaces on biodegradable polymer scaffolds for tissue engineering. Cell-selective biomaterials can be prepared using copolymers containing peptide sequences derived from extracellular-matrix proteins (ECM). Here we discuss alternative ways for preparation of amphiphilic block copolymers composed of hydrophobic polylactide (PLA) and hydrophilic poly(ethylene oxide) (PEO) blocks with cell-adhesion peptide sequences. Copolymers PLA-b-PEO were prepared by a living polymerisation of lactide in dioxane with tin(II)2-ethylhexanoate as a catalyst. The following approaches for incorporation of peptides into copolymers were elaborated. (a) First, a side-chain protected Gly-Arg-Gly-Asp-Ser-Gly (GRGDSG) peptide was prepared by solid-phase peptide synthesis (SPPS) and then coupled with delta-hydroxy-Z-amino-PEO in solution. In the second step, the PLA block was grafted to it via a controlled polymerisation of lactide initiated by the hydroxy end-groups of PEO in the side-chain-protected GRGDSG-PEO. Deprotection of the peptide yielded a GRGDSG-b-PEO-b-PLA copolymer, with the peptide attached through its C-end. (b) A protected GRGDSG peptide was built up on a polymer resin and coupled with Z-carboxy-PEO using a solid-phase approach. After cleavage of the delta-hydroxy-PEO-GRGDSG copolymer from the resin, polymerisation of lactide followed by deprotection of the peptide yielded a PLA-b-PEO-b-GRGDSG block copolymer, in which the peptide is linked through its N-terminus.
authors.affiliation: Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Sq. 2, 162 06 Prague 6, Czech Republic.
authors.forename: Vladimír
authors.initials: V
authors.lastname: Proks
authors.forename: Lud'ka
authors.initials: L
authors.lastname: Machová
authors.forename: Stepán
authors.initials: S
authors.lastname: Popelka
authors.forename: Frantisek
authors.initials: F
authors.lastname: Rypácek
mesh_terms: D001673:Biodegradation, Environmental; D001704:Biopolymers; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry*
chemical_list: D001704:Biopolymers; D015815:Cell Adhesion Molecules; D010455:Peptides