Novel nanohydroxyapatite (nHAp)-based scaffold doped with iron oxide nanoparticles (IO), functionalized with small non-coding RNA (miR-21/124) modulates expression of runt-related transcriptional factor 2 and osteopontin, promoting regeneration of osteoporotic bone in bilateral cranial defects in a senescence-accelerated mouse model (SAM/P6).PART 2