Human BMP2 adenoviral particles

The use of 3D printed gene-activated bone grafts represents a very promising approach in the dental and orthopedic fields. Bioresorbable poly-lactic-co-glycolic acid (PLGA) scaffolds infused with adenoviral constructs carrying genes for osteoinductive factors may offer an effective alternative to existing bone grafts for the reconstruction of large bone defects. Here, researchers aimed to confirm the in vitro and in vivo properties of 3D scaffolds composed of PLGA and adenoviral constructs carrying the BMP2 gene (Ad-BMP2). The elastic modulus of disc-shaped PLGA scaffolds created using a specialized 3D printer was determined by compression testing in both the axial and radial directions. In vitro cytocompatibility was assessed using adipose-derived stem cells (ADSCs). The ability of Ad-BMP2 to transduce cells was evaluated. The osteoinductive and biocompatibility properties of the scaffolds were also evaluated. The Young's modulus of the 3D printed PLGA scaffolds showed comparable values in both the axial and radial compression directions, with axial compression measured at 3.4 ± 0.7 MPa and radial compression measured at 3.17 ± 1.4 MPa. The scaffolds promoted cell adhesion and had no cytotoxic effects on ADSCs. Ad-BMP2 successfully transduced cells and induced osteogenic differentiation in vitro. In vivo studies demonstrated that the 3D printed PLGA scaffolds had osteoinductive properties and promoted bone formation within the scaffold filaments as well as in the center of the critical calvarial bone defect.

The osteoinductive and biocompatible properties were investigated by implantation into the critical defect of rat calvarial bone. After 56 days, bone tissue ingrowth was observed in or around the filaments of the PLGA+Ad-BMP2 scaffolds. After implantation of the plain PLGA scaffold connective tissue, macrophages migrated within the filaments, and no newly formed bone tissue was detected inside the material. It grew only from the edges of the defect. The center of the empty defect ("control") was filled with connective tissue, and there were also foci of newly formed bone tissue at the periphery in contact with the rat bone (Figure 1).

Figure 1. Histological study of a critical-size rat calvarial bone defect after implantation. (Vasilyev A V, et al., 2024)