Collagen–Platelet-Rich Plasma Mixed Hydrogels as a pBMP2 Delivery System for Bone Defect Regeneration

<b>Background/Objectives:</b> The replenishment of bone deficiency remains a challenging task in clinical practice. The use of gene-activated matrices (GAMs) impregnated with genetic constructs may be an innovative approach to solving this problem. The aim of this work is to develop collagen-based matrices with the addition of platelet-rich plasma, carrying polyplexes with the <i>BMP2</i> gene, to study their biocompatibility and osteogenic potential in vitro and in vivo. <b>Methods:</b> The cytocompatibility of the materials during incubation with adipose-derived stem cells (ADSCs) was studied using the MTT test and fluorescent microscopy. Biocompatibility was assessed during intramuscular implantation, followed by histological analysis. Osteogenic differentiation was determined by the expressions of <i>Alpl</i> and <i>Bglap</i> using real-time PCR and extracellular matrix (ECM) mineralization by alizarin red staining. The efficiency of bone regeneration was studied using micro-CT and analysis of histological sections stained according to Masson. <b>Results:</b> After the incubation of ADSCs with GAS, significant increases in the expressions of the <i>Alpl</i> and <i>Bglap</i> genes by 3 ± 0.1 and 9.9 ± 0.6 times, relative to the control, as well as mineralization of the ECM, were observed. The volume of newly formed bone was 37.2 ± 6.2% after implantation of GAS, 20.9 ± 1.2%-non-activated Col/PRP, and 2.6 ± 1.5% in an empty defect. <b>Conclusions:</b> The use of Col/PRP-based matrices is an effective method for delivering of the osteoinductor gene to the site of bone tissue damage. The highest degree of healing was observed after the implantation of Col/PRP-TF/pBMP2 into the critical size defect compared to the other groups.