(99.9%), yttrium(III)
oxide (99.9%), ytterbium(III) oxide (99.9%), and thulium(III) oxide
(99.9%) were purchased from Alfa-Aesar (Haverhill, MA, USA). OA (90%),
ODE (90%), oleylamine (97%), hydrochloric acid (37%), trifluoroacetic
acid (TFA, 99%), sodium trifluoroacetate (98%), sodium hydroxide (≥97%),
ammonium fluoride (≥98%), anhydrous methanol (99.8%), toluene
(99.7%), n-hexane (97%), ethanol (99.8%), PBS, and
AlamarBlue cell viability reagent were purchased from Sigma-Aldrich
(St. Louis, MO, USA). Sodium neridronate and PEG-Ner were prepared
according to earlier reports.40 (link),61 (link) The cellulose dialysis
membrane (Mw cutoff 14 kDa) was purchased
from Spectrum Europe (Breda, Netherlands). In the experiments, Q-water
ultrafiltered on a Milli-Q Gradient A10 purification system (Millipore,
Molsheim, France) and all chemicals were used as received without
further purification.