Makoto Iwatsuki

Fibroblast attachment to Arg-Gly-Asp peptide-immobilized poly(γ-methyl L-glutamate)

The attachment of MRC-5 human fibroblasts was investigated on poly(γ-methyl L-glutamate) (PMLG), and upon cell adhesion peptides Arg-Gly-Asp-Ser (RGDS)- and Gly-Arg-Gly-Asp-Ser (GRGDS)-immobilized PMLG (RGDS-PMLG and GRGDS-PMLG). The peptides were immobilized by their N-terminal amine to activated PMLG surfaces. Prior to peptide immobilization, the aminolysis of PMLG surfaces was performed with hydrazine hydrate (HA), ethylenediamine (EDA), and hexamethylenediamine (HMDA) and was followed by the activation with hexamethylene diisocyanate. Surface characterization of these films was carried out by means of a Fourier transform IR (FT-IR) spectrometer equipped with an attenuated total reflectance (ATR) attachment. The amount of immobilized RGDS could be controlled by the reaction time of the aminolysis. The effects of HA, EDA, and HMDA as a spacer on the cell attachment were also investigated, and it was suggested that a longer spacer promoted the cell attachment via specific receptor-ligand interaction.

Preparation and properties of copoly(n-hydroxyalkyl-d,l-glutamine) membranes

Abstract Random copolypeptide (PHADLG) membranes consisting of N-hydroxyalkyl- d -glutamine (HADG) and N-hydroxylalkyl- l -glutamine (HALG) covering the whole range of d,l -copolymer composition were prepared by carrying out aminolysis reactions with 3-amino-1-propanol (P) or 5-amino-1-pentanol (Pe), together with a crosslinking reaction with 1,8-octamethylenediamine (OMDA) on membranes of the starting random copolymers (PBDLG) consisting of γ-benzyl- d -glutamate and γ-benzyl- l -glutamate. The relationships between their bulk structure and membrane properties were investigated, such as the swelling ratio in water, tensile properties, water vapour permeability, and enzymatic degradation behaviour of the membranes in a pseudo-extracellular fluid (PECF), as a function of d,l -copolymer composition. The tensile properties of d,l -copolymer membranes were highly dependent on the swelling ratio of PECF. Biodegradation of these membranes in vitro by papain indicated that degradation was a bulk rather than a surface phenomenon, and that the rate of degradation of membranes was also highly dependent on the hydrophobicity of side chains, d,l -copolymer composition as well as on the swelling ratios of the d,l -copolymer samples.

Biodegradation of random copolypeptide membranes consisting of N-hydroxyalkyl L-glutamine as one component.

Two component random copolypeptide membranes, consisting of N-hydroxyalkyl L-glutamine and L-alanine or L-leucine were prepared by carrying out aminolysis reactions with 2-amino-1-ethanol (E) or 5-amino-1-pentanol (Pe), together with a cross-linking reaction with 1,8-octamethylenediamine (OMDA) on membranes of the starting copolymers consisting of gamma-benzyl L-glutamate (B) and L-alanine (A) or L-leucine (L). The relationships between their bulk structure and membrane properties were investigated, such as the swelling ratio in water, aqueous vapour permeability, tensile properties and enzymatic degradation behaviour of the membranes in a pseudo-extracellular fluid (PECF). The tensile properties of the hydrophilic membranes were highly dependent on the swelling ratio of PECF, and the hydrophobicity of the side chains, whose behaviour was typical of an elastomer. We showed that a common relation was obtained between the rate of water vapour permeability and the swelling ratio of membranes in PECF despite the difference of the nature of the side chains. Biodegradation of these membranes in vitro by bromelain indicated that the degradation was a bulk rather than a surface phenomenon, and that the rate of degradation was also highly dependent on the swelling ratio of samples and on the hydrophobicity of the side chains of samples.