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[B10H10]2– Nanoclusters Covalently-Immobilized to Hybrid SiO2 Aerogels for Slow Neutron Shielding Applications
An alkoxysilane derivative bearing 10-vertex closo-decaborate nanocluster (B10H102–) was successfully synthesized and immobilized in SiO2 aerogel matrix. closo-Decaborate-containing SiO2 aerogels showed high specific surface (~750 m2/g), open porosity (~95 %) and extremely low apparent density (80 mg/cm3) as well as increased thermal stability of closo-decaborate moiety. Despite the low boron content (~1.2 mol.% of boron nanoclusters comprising natural mixture of boron isotopes), the aerogel nanomaterial demonstrated excellent neutron capture properties exceeding lightweight polymer-based analogues. Cell viability assessment indicated the pronounced dose-dependent toxicity of borylated aerogel with respect to malignant cells (U251 MG glioblastoma line), and low toxicity with respect to normal cells (dental pump stem cells). The combination of the properties of closo-decaborate modified silica aerogels make them good candidate material for shielding of patients and healthcare personnel during boron neutron capture therapy procedures.