Table 1 Compilation of encapsulation experiments reported in literature
Nanoparticle type and size | label | labelling yield/label leaching | Retention/release of daughter nuclides | remarks | reference |
|---|---|---|---|---|---|
Zwitterionic pegylated phosphatydylcholine cholesterol liposomes 200 / 400 / 650 nm | 225Ac | 225Ac retention > 88% for zwitterionic liposomes after 30d | 213Bi retention ≈ 12% for 650 nm size liposomes after 2 days and ≈4% after 30 days | Retention values for 225Ac and 213Bi lower for cationic liposomes | Sofou et al., 2004 |
liposomes | 225Ac | Yield (73±9)% / retention up to (81±7)% achievable | Funtionalised liposomes maintain targeting efficacy after 225Ac loading | Chang et al., 2008 | |
Polymersomes 100 / 200 /400 /800 nm filtered fractions | 225Ac | (67±0.8)% in 30 min leaching - 200 nm: 2% after 8d 7% after 28d | highest retention after 24h 800 nm: 221Fr (69±1.5)% 213Bi (53±4)% 100 nm: 221Fr (37±4)% 213Bi (22±1)% | Polymerosomes can be internalized by target cells | Wang et al., 2014 |
[225Ac]InPO4 nanoparticles Inside polymersomes 100 / 200 /400 /800 nm filtered fractions | 225Ac | Retention of 225Ac in polymersomes containing [225Ac]InPO4 nanoparticles (92±3)% | retention after 24h 100 nm: 221Fr ≈ 57% 213Bi ≈ 40% | Amorphous [225Ac]InPO4 nanoparticles (≈ 20 nm) were created inside the polymersomes; works well for polymersomes < 400 nm | De Kruijff et al., 2017 |
Hydroxylapatite XRD: 15 nm | 223Ra | 99% yield achievable /Release after 24 h in saline 0.7% (surface absorption) 0.8% (in synthesis labelling) | Labelling during synthesis and after synthesis (surfacesorption) show both very low leaching – re-absorption on surface? | Kozempel et al., 2015 | |
Hydroxylapatite TEM: nanoplates ≤ 100nm x ≤ 500nm x 0.8…2.4 nm | 223Ra | Labelling yield (97±1)% in 20 h /6% - 15% released within 24h depending on loading strategy | After surface sorption: 8% loading during synthesis: 15% + annealing 900oC, 3h: 6% release during 24h | Vasiliev et al., 2016 | |
Nanozeolite XRD 43 nm SEM 50-170 nm DLS 40-120 nm | 224Ra 225Ra | Labelling yield >99.9% leaching < 0.5% (4d) | Release 1d after incubation 224Ra: 212Pb (2.6±1.5)% 208Tl (7.9±0.9)% 212Pb (6.2±0.5)% Release 1d after incubation 225Ra: 225Ac (2.3±1.9)% 221Fr(2.7±0.2)% 213Bi(7.4±0.8)% | daughter release data reported in human blood serum (data available also for other media) | Piotrowska et al., 2013 |
Functionalised Nanozeolite-silane-PEG-SP(5-11)TEM: 60 nm | 223Ra | labelling yield > 99.9% leaching < 0.5% | released daughter nuclides 211Pb and 211Bi increasing from ≈2% (1d) to ≈5% (6d), each | High receptor affinity preserved; intravenous application not possible | Piotrowska et al., 2017 |
Fe3O4 SPIONS TEM: 4…26 nm DLS: 284 nm | 223Ra | Yield in 0.9% NaCl ≤ 50% , in PBS 85-99% within 1h Leaching in bovine serum and plasma 1.5% (11.4d) to 2% (22.8d) | Labelling by surface complexation suggested | Mokhodoeva et al., 2016 | |
{La 0.5 Gd 0.5}PO4 core (2.9±0.7) nm +4 shells GdPO4 + external Au shell 27 nm (with Au shell) (22.4±7.7)nm | 225Ac | 76% after 4 days of core synthesis 225Ac retention > 99.9% after 3 weeks | 221Fr retention ≈90% after 3 weeks | Ac will co-crystallize into a lanthanide phosphate crystal Gd allows separation of 225Ac-labelled NPs from co-produced Au-NPs | McLaughlin et al., 2013 |