Conclusion
This work demonstrated that E2-csUCNP@MSN-EDTA alleviates the side effect of hormone therapy while maintaining its therapeutic efficacy, which has great potential for developing the next generation of methods for osteoporosis treatment.
Methods
Herein, a 17β-estradiol (E2)-laden mesoporous silica-coated upconversion nanoparticle with a surface modification of ethylenediaminetetraacetic acid (EDTA) (NaLuF4:Yb,Tm@NaLuF4@mSiO2-EDTA-E2, E2-csUCNP@MSN-EDTA) is developed for bone-targeted osteoporosis hormone therapy. EDTA was attached onto the surface of E2 upconversion nanocomposite to enhance its affinity and efficiency targeting bone tissue and cells to optimize hormone replacement therapy for osteoporosis. We characterized the size, cytotoxicity, loading and release efficiency, in situ and ex vivo imaging. Further, in vitro and in vivo osteogenic ability was tested using preosteoblast and ovariectomy mouse model of osteoporosis.
Results
The upconversion core of E2-csUCNP@MSN-EDTA nanoparticle serves as an excellent imaging agent for tracking the loaded hormone drug in vivo. The mesoporous silica layer has a high loading efficiency for E2 and provides a relatively long-lasting drug release within 50 h. EDTA anchored on the silica layer endows the nanocomposite with a bone targeting property. The nanocomposite effectively reverses estrogen deficiency-induced osteoporosis and reduces the damage of hormone to the uterus. The bone mineral density in the nanocomposite treatment group is nearly twice that of the ovariectomized (OVX) group. Compared with the E2 group, the uterine weight and luminal epithelial height were significantly lower in the nanocomposite treatment group.