Sequential dual‑drug delivery of BMP‑2 and alendronate from hydroxyapatite‑collagen scafolds for enhanced bone regeneration

Dongtak Lee, Maierdanjiang Wufuer, Insu Kim, Tae Hyun Choi , Byung Jun Kim , Hyo Gi Jung, Byoungjun Jeon, Gyudo Lee, Ok Hee Jeon, Hak Chang & Dae Sung Yoon - School of Biomedical Engineering, Korea University, Seoul ; College of Medicine, Seoul National University

The clinical use of bioactive molecules in bone regeneration has been known to have side effects, which result from uncontrolled and supraphysiological doses.

In this study, we demonstrated the synergistic effect of two bioactive molecules, bone morphogenic protein-2 (BMP-2) and alendronate (ALN), by releasing them in a sequential manner. Collagen-hydroxyapatite composite scaffolds functionalized using BMP-2 are loaded with biodegradable microspheres where ALN is encapsulated.
The results indicate an initial release of BMP-2 for a few days, followed by the sequential release of ALN after two weeks. The composite scaffolds significantly increase osteogenic activity owing to the synergistic effect of BMP-2 and ALN. Enhanced bone regeneration was identified at eight weeks postimplantation in the rat 8-mm critical-sized defect. Our findings suggest that the sequential delivery of BMP-2 and ALN from the scaffolds results in a synergistic effect on bone regeneration, which is unprecedented. Therefore, such a system exhibits potential for the application of cell-free tissue engineering.

How Amira-Avizo Software is used

New bone formation in the defects was evaluated using the AMIRA software. To measure newly formed bone, a circular area of predefined size was selected as the region of interest (ROI) in the two-dimensional images.