Isamu Miyata

Recyclable characteristics of hyaluronate-polyhydroxyethyl acrylate blend hydrogel for controlled releases.

Hyaluronate-hydroxyethyl acrylate blend hydrogels which have a wide range of composition and characteristics were investigated. Glycidyl methacrylate derivatized hyaluronate (GMA-HA) were synthesized by coupling GMA to hyaluronate (HA) in the presence of a photoinduced initiator for polymerization. By copolymerizing radically GMA-HA and hydroxyethyl acrylate (HEA) under various compositions (weight ratios of HEA and GMA-HA: 1-20), GMA-HA hydrogels could be prepared in wide ranges of characteristics. These HA-PHEA gels possessed the feature that the dried ones recovered completely to the original swelling states on repeated runs, i.e. recyclable gels. The water contents of these hydrogels in equilibrium swellings in water (W(w)) were 0.99-0.86, and their viscoelastic properties were measured by a creep. The spontaneous elastic moduli were 1.05x10(5)-1.94x10(5) N m(-2), and they were mechanically tough. Their effective charge densities were estimated from the partition coefficients of sodium benzoate (NaBA) and decreased from -0.033 to -0.044 mol dm(-3) with increasing contents of HEA. Release of NaBA was studied, and the diffusion coefficients were found to be from 6.95x10(-10) to 0.12x10(-10) m(2) s(-1) with increasing the ratio of HEA. Their diffusion coefficients were found to be much less than the values estimated from the lattice model.

Two Dimensional Auto-organized Nanostructure Formation of Hyaluronate on Bovine Serum Albumin Monolayer and its Surface Properties

The layer-by-layer interaction between sodium hyaluronate (NaHA) and bovine serum albumin (BSA) were studied by a quartz crystal microbalance (QCM) method. Their surface structures, adhesive force F ad and frictional behavior were investigated using an atomic force microscope (AFM). The adsorptions of NaHA on the BSA monolayer were found to be the Langmuir type. The surface structures of NaHA adsorbed on the BSA monolayer were found to form hexagonal-like networks and the mesh size decreased with increasing molecular weight M w. The F ad between the AFM tip and the surfaces of the saturated NaHA layers increased with increasing value of M w. However, the frictional coefficient of saturated NaHA layer was found to decrease from 0.933 to 0.191.