(P 261) Modification of Polylactide Surfaces with PLA-b-PEO Block Copolymers Deposited from Selective Solvents

Amphiphilic di-block copolymers composed of polylactide (PLA) and omega-methoxy-poly(ethylene oxide) (mPEO) in selective solvents can associate to micelles and/or with surfaces compatible with PLA block. Formation of surface brush layers based on deposition of PLA-b-PEO copolymers from selective solvents is studied as a method of surface modification of PLA-based bio-materials for tissue engineering. A series of PLA-b-PEO copolymers with different molecular parameters, block lengths and stereoregularity of PLA block (DL or L) were synthesized and characterized by super(1)H NMR spectroscopy and SEC. The solution properties and self-association of copolymers in various solvent mixtures, such as acetone/methanol, dioxane/methanol, acetone/ water, were investigated by dynamic light scattering (DLS) and the size distribution and stability of aggregates were related to molecular parameters of copolymers and mixed solvent composition. Selected compositions of copolymer micelles (nanoparticles) were deposited by spin-casting on poly(L-lactide) surfaces. The surface properties of PLA modified with deposited copolymer films were characterized by contact angle measurements and the stability of films in aqueous environments was evaluated. The efficiency and stability of PLA surface modification, based on wettability changes was related to the solution properties and molecular parameters of copolymers. The most efficient surface modification was achieved by deposition of PLLA-b-PEO with 10 KDa PEO block. The support by Academy of Sciences of CR (1QS500110564), Center for Cell Therapy and Tissue Repair (MSMT: 1M0021620803) and 6FP-EU NoE "EXPERTISSUES" (NMP3-500283-2) is acknowledged.