Table 2. Calorimetry Detailsa.
| PEI size (kDa) | pH | N (sites) | KD (μM) | ΔH (kcal/mol) | ΔG (kcal/mol) | −TΔS (kcal/mol) |
|---|---|---|---|---|---|---|
| 1.3 | 7.4 | 1.41 ± 0.03 | 0.70 ± 0.13 | −0.82 ± 0.02 | −8.41 ± 0.11 | −7.59 ± 0.01 |
| 5.5 | 1.33 ± 0.27 | 32.4 ± 8.2 | −2.65 ± 0.27 | −6.29 ± 0.18 | −3.64 ± 0.41 | |
| 5.0 | 7.4 | 1.97 ± 0.10 | 2.94 ± 0.64 | −0.97 ± 0.02 | −7.57 ± 0.14 | −6.60 ± 0.15 |
| 5.5 | 1.34 ± 0.28 | 20.7 ± 8.1 | −2.38 ± 0.37 | −6.44 ± 0.23 | −4.10 ± 0.60 | |
| 10 | 7.4 | 2.20 ± 0.14 | 0.26 ± 0.14 | −0.22 ± 0.06 | −9.11 ± 0.49 | −8.89 ± 0.54 |
| 5.5 | 2.16 ± 0.09 | 1.15 ± 0.97 | −1.39 ± 0.12 | −8.42 ± 0.85 | −7.03 ± 0.95 | |
| 25 | 7.4 | 2.38 ± 0.10 | 5.00 ± 1.53 | −1.09 ± 0.05 | −7.26 ± 0.19 | −6.17 ± 0.18 |
| 5.5 | 2.01 ± 0.21 | 3.72 ± 2.29 | −1.60 ± 0.14 | −7.53 ± 0.48 | −5.93 ± 0.62 |
a
Calorimetric parameters (N-sites, KD, enthalpy change, Gibbs free energy change, entropy change) as obtained via micro-ITC for the complexation of siRNA with different PEIs at two pH levels. Data indicate mean ± SD (n = 4).