Sustained dual release of placental growth factor-2 and bone morphogenic protein-2 from heparin-based nanocomplexes for direct osteogenesis

Abstract

Yun Liu,1,* Li-Zhi Deng,2,3,* Hai-Peng Sun,1 Jia-Yun Xu,1 Yi-Ming Li,1 Xin Xie,1 Li-Ming Zhang,2,3 Fei-Long Deng1 1Department of Oral Implantology, Guangdong Provincial Key Laboratory of Stomatology, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, People’s Republic of China; 2PCFM Lab, 3GDHPPC Lab, Institute of Polymer Science, Department of Polymer and Materials Science, School of Chemistry and Chemical Engineering, Sun Yat-sen University, Guangzhou, People’s Republic of China *These authors contributed equally to this work Objective: To compare the direct osteogenic effect between placental growth factor-2 (PlGF-2) and bone morphogenic protein-2 (BMP-2). Methods: Three groups of PlGF-2/BMP-2-loaded heparin–N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) nanocomplexes were prepared: those with 0.5 µg PlGF-2; with 1.0 µg BMP-2; and with 0.5 µg PlGF-2 combined with 1.0 µg BMP-2. The loading efficiencies and release profiles of these growth factors (GFs) in this nanocomplex system were quantified using enzyme-linked immunosorbent assay, their biological activities were evaluated using cell counting kit-8, cell morphology, and cell number counting assays, and their osteogenic activities were quantified using alkaline phosphatase and Alizarin Red S staining assays. Results: The loading efficiencies were more than 99% for the nanocomplexes loaded with just PlGF-2 and for those loaded with both PlGF-2 and BMP-2. For the nanocomplex loaded with just BMP-2, the loading efficiency was more than 97%. About 83%–84% of PlGF-2 and 89%–91% of BMP-2 were stably retained on the nanocomplexes for at least 21 days. In in vitro biological assays, PlGF-2 exhibited osteogenic effects comparable to those of BMP-2 despite its dose in the experiments being lower than that of BMP-2. Moreover, the results implied that heparin-based nanocomplexes encapsulating two GFs have enhanced potential in the enhancement of osteoblast function. Conclusion: PlGF-2-loaded heparin–HTCC nanocomplexes may constitute a promising system for bone regeneration. Moreover, the dual delivery of PlGF-2 and BMP-2 appears to have greater potential in bone tissue regeneration than the delivery of either GFs alone. Keywords: placental growth factor-2, bone morphogenic protein-2, heparin, nanocomplexes, osteogenesis

Keywords

• placental growth factor-2
• bone morphogenic protein-2
• heparin
• nanocomplexes
• osteogenesis