Table 3.
Diffusion coefficients D, relaxation times, T1 and T2, of peptides in solutions and in hydrogels.a
| Temperature | Sample | D (10−10 m2·s−1) | T1 (ms) | T2 (ms) |
|---|---|---|---|---|
| 5°C | EAW10 solution | 0.63 | 368.4 | 178.1 |
| OAW10 solution | 0.61 | 361.1 | 175.2 | |
| 5°C gel | 0.64 (0.02) | 242.8 (7.1) | 111.1 (3.1) | |
| 25°C → 5°C gel | 0.66 (0.16)b | 125.4 (3.3) | 29.8 (1.3) | |
|
| ||||
| 25°C | EAW10 solution | 0.98 | 445.2 | 274.3 |
| OAW10 solution | 1.03 | 452.6 | 274.2 | |
| 25°C gel | 1.08 (0.13)b | 148.2 (3.1) | 42.3 (3.2) | |
| 5°C → 25°C gel | 1.28 (0.13)b | 204.1 (5.1) | 91.4 (2.4) | |
For hydrogels, the numbers represent the average value and standard deviation (in parentheses), which is based on 10 data points except that for the 25°C → 5°C gel, which is based on 4 data points. The D, T1 and T2 values were obtained from the 1H signal of the -CH3 groups in peptides. Using the 1H signal from the -CH2- groups in peptides, very similar D values are obtained: D(5°C gel) = 0.61±0.01; D(25°C → 5°C gel) = 0.62±0.12; D(25°C gel) = 1.07±0.12; D(5°C → 25°C gel) = 1.14±0.04, all in 10−10 m2·s−1. However, -CH2- groups give T1 and T2 values different from -CH3 groups, as shown in Fig. 4.
As a result of gelation, these NMR spectra had a poor signal to noise ratio, and leads a bigger standard deviation consequently.