Alendronate-modified hydroxyapatite nanoparticles for bone-specific dual delivery of drug and bone mineral

Abstract

Alendronate (Alen)-modified hydroxyapatite (HAp) nanoparticles with multilayers of poly(allylamine) (PAA) and alginate (ALG) were fabricated for bone-specific dual delivery of drug and mineral. Negatively charged HAp nanoparticles were coated with three layers of PAA and ALG using a layer-by-layer (LbL) method and then conjugated with Alen at the outmost layer of the LbL-coated HAp nanoparticles via carbodiimide chemistry. Alen-modified HAp nanoparticles had a spherical morphology and an average size of 61.5 nm. The superior adsorption property of the Alen-modified HAp nanoparticles was quantitatively confirmed using tricalcium phosphate disks as a bone model, compared to HAp nanoparticles. Cell culture assays revealed a higher proliferation rate and alkaline phosphatase activity of osteoblasts treated with the Alen-modified HAp nanoparticles.