Development of a zoledronate-modified functional alginate hydrogel with effects of promoting osteogenesis for potential osteoporosis treatment

Osteoporosis is one of the most prevalent age-related diseases worldwide. It is characterized by a systemic deterioration in bone strength (bone density and bone mass), leading to an increase in fragility fractures. The complex pathological environment of osteoporosis presents a significant challenge to the induction of bone regeneration under osteoporotic conditions. Therefore, the development of a system for local delivery of active substances with osteoinductive effects is of practical significance in the clinical treatment of osteoporosis. In this study, we successfully loaded the anti-osteoporotic small molecule drug zoledronate (ZOL) into calcium alginate to prepare a biologically functional hydrogel, designated as ALG-ZOL-Ca. The prepared ALG-ZOL-Ca hydrogel gels quickly, making the hydrogel easy to inject and adapt to irregularly shaped bone defects, and simultaneously exhibits good bioactivity and osteoconductivity. The RT-qPCR results suggested that this hydrogel effectively promoted the expression levels of β-catenin and Axin2, which indicating a stimulative effect on the Wnt/β-catenin pathway in vitro. Moreover, ALG-ZOL-Ca hydrogel effectively promoted the expression of the OCN and SP7 genes. Therefore, this study proposes a new functional composite hydrogel that provides a potential treatment strategy for osteoporosis.