Properties of biomimetic polypeptides materials: Biomimetic adhesive and ethylene glycol functionalized-beta-sheet forming polypeptides

Biomimetic adhesives containing 3,4-dihydroxyphenyl-L-alanine (DOPA) and L-lysine have been prepared by ring opening polymerization of α-amino acid-N-carboxyanhydride (NCA) monomers. Our experiments have shown that the catechol functionality is primarily responsible for moisture-resistant adhesion and that the oxidized o-quinone functionality is primarily responsible for cross-linking. To optimize the developed system of biomimetic adhesives, 4-aminophenyl functionalized amino acids were prepared and characterized. Results showed the presence of Michael adduct by crosslinks of poly(N_ϵ-(4-aminophenylacetyl)-L-lysine) or poly(4-aminophenyl-L-alanine) with poly((L-Lys·HBr) ₉-(L-DOPA)₁), however, the adhesive strengths were not significantly improved.; We have synthesized methylated mono- and di(ethylene glycol)-functionalized polymers of L-serine and L-cysteine that adopt, β-sheet conformations in the solid state: poly(O-(2-(2-methoxyethoxy)ethyl)-L-serine), 1; poly(O-(2-(methoxy)ethyl)-L-serine), 2; and poly(S-(2-(2-methoxyethoxy)ethoxy)-carbonyl-L-cysteine), 3. Of these three polymers, only 1 was found to be highly soluble in water independent of pH.; Novel rod-coil block copolypeptides were found to assemble in water or water/THF (90/10) as aggregates with morphologies that varied with volume fraction and amino acid composition. The hydrophilic block of poly((O-(2-(2-ethoxy-methoxy)ethyl)-L-serine) _0.5-(N_ϵ-2-[2-(2-methoxyethoxy)ethoxy)]acetyl-L-lysine) _0.5) poly((PEG-Ser)_0.5-(PEG-Lys)_0.5) was prepared with the various hydrophobic blocks such as poly(L-leucine); poly(L-alanine); and poly(L-leucine_0.75/L-valine_0.25). Triblock copolypeptide, poly((PEG-Ser)_0.5-(PEG-Lys)_0.5) ₉₀-block-poly(leucine_0.75-valine_0.25 )₂₀-block-poly(PEG-Lys)₂₀, was also prepared to study the effect of decreasing the interfacial curvature on the self-assembly of the polymers in comparison with diblock amphiphilic copolymers.; We have prepared novel, water soluble, non-ionic/ionic diblock copolypeptides and studied their assembly in water. Electrostatic interactions between cationic and anionic polypeptide segments result in aggregation into supramolecular structures. The following ionic block copolypeptides were prepared: poly((PEG-Ser) _0.5-(PEG-Lys)_0.5))_x-block-(L-Lys ·HBr)y) 1 (x:y = 0.90:0.10), 2 (x:y = 0.80:0.20) and poly((PEG-Ser)_0.5-(PEG-Lys)_0.5)) _x-block-(L-Asp·Na)_y) 3 (x:y = 0.90:0.10), 4 (x:y = 0.80:0.20). Evaluation of the aggregation behavior of these materials, 1 + 3 and 2 + 4 using TEM showed the existence of various morphologies.