Ludox cl x colloidal silica

A precursor suspension is prepared by mixing 22 wt.% poly(ethylene glycol) diacrylate (PEG-DA, Mn = 700 g/mol, Sigma-Aldrich), 74 wt.% LUDOX CL-X colloidal silica (45 wt.% suspension in H₂O, Sigma-Aldrich) and 4 wt.% 2-Hydroxy-2-methyl-propiophenone (PI, Darocur 1173, Sigma-Aldrich). After synthesis, the tetrahedrons are collected and washed with 0.5 v/v % Tween-20 (Sigma-Aldrich) solution in water.

All chemicals were of analytical grade and used without further purification. Aluminum isopropoxide (≥98% purity) as Al source, LUDOX CL-X colloidal silica (45% suspension in water) as Si source, sodium hydroxide (≥97% purity) as cation source, and tetramethylammonium hydroxide (TMAOH) solution (25 wt.% in water) as template were purchased from Sigma-Aldrich. Deionized water was obtained from Merck Millipore equipment (Saint Louis, MO, USA). All above reagents were used for synthesis of NaA zeolite powders. Etoxy silane functionalized polyethylene glycol (silane-PEG, 5000 Da) from Nanocs (Boston, MA, USA) and ethanol (96% and 99.8% in water) from POCH (Gliwice, Poland) were used for the silanization process. 2-iminothiolane (2-IT), sodium bicarbonate (NaHCO₃), ethylenediaminetetraacetic acid (EDTA), glycine, Ellman’s reagent, m-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS) and dimethylformamide (DMF) from Sigma-Aldrich (Lenexa, KS, USA) were used for the conjugation of anti-PSMA monoclonal antibodies (D2B) to silane-PEG-nanozeolite. Radionuclide of ²²³Ra was isolated by a radiochemical separation from the ²²⁷Ac source obtained from the Institute for Transuranium Elements (Karlsruhe, Germany) in the amount of 3 MBq. Radionuclide of ¹³³Ba was supplied from the Radioisotope Centre POLATOM (Otwock, Poland).