Dynamic rheological behaviors of hydrogels are analyzed with a Discovery Hybrid Rheometer, using parallel plate geometry (8 mm diameter). Frequency sweep measurements are performed at 37 °C from 0.1 to 100 rad s-1 at a fixed strain in the linear viscoelastic region. 13 C NMR spectra of GMI in DMSO-d6. GMI structure was confirmed by NMR spectra. In Figure . (a) 1 H spectrum shows that the peaks around 13 and at 7.1 ppm are due to the -O-H bond of the carboxylic acid and the -CH=CH-bond of the maleimide ring. In the Figure . (b) 13 C spectrum illustrates that the peaks corresponding to carbonyl groups and the double bond of the maleimide ring appeared at 170.8 and 135.3 ppm, respectively. Furthermore, the peak of the carbonyl group of the carboxylic acid was detected at 169.3 ppm. Dex-MAL structure is confirmed by 1 H NMR spectrum. In Figure , the peak at 6.9 ppm is assigned to protons in the maleimide. The peaks at 4.0-3.4 ppm are attributed to protons in the dextran backbone. The degree of functionality of the PEG-4MAl can be estimated to be about 50% by comparison of the integrals of the resonance signals at 6.9 ppm and 4.0-3.4 ppm. The structure of HA-SH was confirmed by 1 H NMR. HA modification was determined by 1 H NMR analysis using the resonance of the acetamido moiety of HA at δ = 1.95-1.85 ppm as an internal standard. The peaks at δ = 2.7-2.5 ppm correspond to cysteamine in HA-SH. The degree of functionality of the HA-SH can be estimated to be about 10% by comparison of the integrals of the resonance signals at 2.7-2.5 ppm and 1.95-1.85 ppm.