Table 2:
Zeta potential measurements. Fraction of charged lipids dissociated was calculated by comparison of surface charge with theoretical maximum surface charge for each composition (based on mole fraction of charged species and area per lipid of 45 Å2/molecule). Given the similarity in potential trends for DMPS and DMPG, only dissociation data for DMPS:DMPC mixtures is reported.
| 140 mM phosphate buffer, pH 7.4 | ||||
|---|---|---|---|---|
| DMPS:DMPC | Zeta potential ζ, mV | Surface charge σ0, mC/m2 | Fraction of charged lipids dissociated (Approx.%) | Overall lipids dissociated (%) |
| 1:99 | −2 ± 1 | −3 ± 3 | 91 | 1 |
| 5:95 | −9 ± 1 | −15 ± 2 | 82 | 4 |
| 10:90 | −13 ± 2 | −22 ± 3 | 63 | 6 |
| 20:80 | −25 ± 4 | −49 ± 10 | 69 | 14 |
| 30:70 | −31 ± 3 | −68 ± 11 | 64 | 19 |
| 100:0 | −34 ± 3 | −79 ± 15 | 22 | 22 ± 4 |
| 0.5 mM NaNO 3 , pH 5.7 | ||||
| DMPS:DMPC | Zeta potential ζ, mV | Surface charge σ0, mC/m2 | Fraction of charged lipids dissociated (Approx. %) | Overall lipids Dissociated (%) |
| 0.5: 99.5 | −28 ± 2 | −1.6 ± 0.1 | 88 | 0.4 |
| 1:99 | −36 ± 3 | −2.1 ± 0.2 | 60 | 0.6 |
| 5:95 | −55 ± 5 | −3.7 ± 0.4 | 21 | 1.0 |
| 10:90 | −65 ± 3 | −4.6 ± 0.2 | 13 | 1.3 |
| 20:80 | −76 ± 2 | −6.0 ± 0.3 | 8 | 1.7 |
| 100:0 | −68 ± 3 | −5.0 ± 0.4 | 1.4 | 1.4 ± 0.2 |