Table 2.
Effect of Pluronic and Tetronic coatings on MNP characteristics in vitro
| Co-polymer | % Co-polymer bound to MNPs* | Protein binding | Macrophage uptake (µg Fe/µg cell protein)** | Diameter of MNPs (nm) and (Polydispersity Index) | ||||
|---|---|---|---|---|---|---|---|---|
| Kb | n | Water | Mannitol citrate buffer | PBS | BSA after 4 h*** | |||
| Feridex IV | — | 0.111 | 1.58 | 0.051 | 143 (0.29) | — | 126 (0.28) | 113 (0.29) |
| Pluronic F68 | 6.0 | 0.046 | 1.39 | 0.477 | 216 (0.12) | 255 (0.08) | 340 (0.14) | 224 (0.08) |
| Pluronic F108 | 8.6 | 0.090 | 1.55 | 0.168 | 206 (0.09) | 248 (0.11) | 277 (0.17) | 223 (0.08) |
| Pluronic F127 | 14.5 | 0.094 | 1.15 | 0.222 | 194 (0.10) | 238 (0.08) | 257 (0.15) | 228 (0.15) |
| Pluronic L64 | 4.9 | 0.082 | 1.38 | 0.202 | 186 (0.10) | 243 (0.13) | 539 (0.46) | 220 (0.12) |
| Tetronic 904 | 8.5 | 0.075 | 1.48 | 0.198 | 196 (0.15) | 215 (0.12) | 321 (0.21) | 202 (0.15) |
| Tetronic 908 | 7.5 | 0.036 | 1.72 | 0.190 | 228 (0.11) | 253 (0.11) | 257 (0.13) | 236 (0.06) |
*
Co-polymer bound to MNPs was determined by thermogravimetric analysis.
**
0.1 mg /ml particles incubated with the mouse leukemic monocyte macrophage cell line RAW 264.7.
***
Particle size measured following 4 h incubation in the presence of 100 µg/ml BSA in water. Particle size represents hydrodynamic diameter. Core diameter (measured using transmission electron microscopy) was 10–15 nm. MNPs have negative zeta potentials, typically ranging from −20 to −30 mV.
MNPs, magnetic nanoparticles, PBS, phosphate-buffered saline; BSA, bovine serum albumin.