Osteogenic Potential of BMP-2-Releasing Self-Assembled Membranes

Abstract

We report here the use of novel self-assembling collagen-hyaluronic acid (HyA) membranes to deliver bone morphogenetic protein-2 (BMP-2) for orthopedic applications. Prior work has demonstrated that collagen-HyA membranes are formed initially through electrostatic interactions between the oppositely charged collagen and HyA molecules, and that membrane growth is driven by osmotic pressure imbalances between the collagen and HyA solutions. The purpose of this study was to investigate the potential of incorporating charged growth factors such as BMP-2 within the membrane for regenerative medicine applications. Membrane material properties, protein mass loss, and release kinetics of BMP-2, as well as biocompatibility and osteogenic potential in vitro and in vivo using a subcutaneous mouse model were assessed. Scanning electron microscopy and mechanical testing confirmed no loss of structural or mechanical integrity upon BMP-2 incorporation into the membranes. Slow and steady release of the growth factor was demonstrated with 17% of total loaded BMP-2 released over the course of 49 days. To test biocompatibility and osteogenic potential in vitro, human mesenchymal stem cells were cultured on collagen-HyA membranes and showed greater proliferation rates (for up to 28 days) on membranes without BMP-2, but a greater alkaline phosphatase activity and osteocalcin production on membranes releasing BMP-2. In vivo subcutaneous implantation of the membranes showed a minimal immune response with osteoblasts and mineral deposits present in the ectopic site for BMP-2-releasing membranes, further demonstrating the potential of the BMP-2-releasing membranes to induce osteogenic differentiation. This study presents a novel strategy to create self-assembled membranes using two biocompatible molecules that can deliver bioactive agents in a sustained manner to induce a local regenerative response.

A microfluidic 3D in vitro model for specificity of breast cancer metastasis to bone

“…osteonectin and osteopontin, was evaluated within 2D flasks to provide complete evidence of osteogenic differentiation (Fig. S2C and D) [55–57]. Taken together, these findings confirm hBM-MSC osteogenic differentiation, thus providing the potential to better study the specific transendothelial migration of breast cancer cells into bone.…”

Experimental and Computational Investigation of the Effect of Hydrophobicity on Aggregation and Osteoinductive Potential of BMP-2-Derived Peptide in a Hydrogel Matrix

“…The clinically used concentration of BMP-2 protein is 1 mg/mL (*0.04 mM) 48 but the typical concentration used for in vitro 3D experiments is in the 1-10 mg/mL (*0.00004-0.0004 mM) range. 32,33 In this work, the upper concentration of 0.0004 mM was used to elucidate the effect of peptide on differentiation of hMSCs. DNA content, ALP activity, and calcium content of the groups are shown at a single time point (7,14, and 21 days, respectively) in Figure 2a-c. DNA content of the groups at day 7 did not change appreciably with peptide concentration (Fig.…”

“…The cell-encapsulated gels (without BMP-2 peptide) incubated in BM and OM without DEX were used as negative controls while those with 0.0004 mM BMP-2 protein dissolved in the gel (and medium) was used as the positive control. 32,33 For the groups with peptide dissolved in the gel, the peptide was also added to the culture medium for concentration uniformity.…”

Recombinant Human Bone Morphogenetic Protein 9 (rhBMP9) Induced Osteoblastic Behavior on a Collagen Membrane Compared With rhBMP2

“…The present study assesses the local combination of rhBMP9 with collagen membranes. In routine clinical practice, rhBMP2 has demonstrated more favorable clinical absorption properties when combined with a collagen membrane compared to a bone grafting material, 36–38 thus maintaining its bioactivity.…”

“…18,25,[30][31][32][33][34][35] The present study assesses the local combination of rhBMP9 with collagen membranes. In routine clinical practice, rhBMP2 has demonstrated more favorable clinical absorption properties when combined with a collagen membrane compared to a bone grafting material, [36][37][38] thus maintaining its bioactivity. Biomaterials as carriers for growth factors should ideally provide a proper microenvironment facilitating cell recruitment and differentiation toward bone-forming osteoblasts.…”