Table 1. Relaxometry of polymeric contrast agents.
| Particle characteristics | cellulose | cellulose acetate | ester-terminated PLGA | acid-terminated PLGA | Feridex® | Bangs beads | ||
|---|---|---|---|---|---|---|---|---|
| Particle size range | nano | nano | nano | micro | nano | micro | nano | micro |
| Particle size, nm | 413.5 | 533.3 | 130 | 1500 | 105 | 2100 | 150 | 1600 |
| Zeta potential (pH 7.0), mV | -11.4 ± 0.8 | +8.9 ± 0.6 | -12.7 ± 0.5 | -21.3 ± 0.6 | -9.7 ± 1.1 | -18.8 ± 0.7 | -6.7 ± 0.6 | -32.3 ± 0.6 |
| Magnetite content, wt% | 69.6 | 56.4 | 15.3 | 5.1 | 24.7 | 43.3 | 0.19 | 42.5 |
| r2 per mmol Fe, s-1mM-1 | 62.81 | 75.1 | 83.8 | 93.1 | 269.8 | 20.9 | 110.5 | 52.7 |
| r2* per mmol Fe, s-1mM-1 | 398.6 | 399.0 | 262.6 | 554.5 | 505.0 | 261.0 | 214.8 | 454.7 |
| r2 per mmol particlesa (×1010), s-1mM-1 | 3.73 | 5.82 | 0.0172 | 9.08 | 0.0513 | 66.6 | 0.000298 | 58.9 |
| times better thanb Feridex® | 12500 | 19500 | 57.6 | 30500 | 172 | 224000 | 1 | 198000 |
| r2* per mmol particles (×1010), s-1mM-1 | 23.7 | 30.9 | 0.0538 | 54.1 | 0.096 | 832 | 0.000579 | 508 |
| times better than Feridex® | 40900 | 53400 | 92.9 | 93400 | 166 | 1440000 | 1 | 878000 |
a
1 mmol of particles = 6.02 × 1020 particles
b
ratios are rounded to 3 significant figures