Characteristics of freeze-dried bovine hydroxyapatite (BHA)—secretome composites as bone graft candidates

The effect of the secretome addition to the bovine hydroxyapatite (BHA) as a bone graft candidate was observed through some in vitro testing, histopathological anatomy test, and immunohistochemistry test. BHA and secretomes are first synthesized and then immersed in secretomes to gain the BHA-secretome composite scaffold. The scaffold was freeze-dried and underwent some in vitro and in vivo tests such as morphology, functional group, MTT assay, degradation, and swelling tests. The in vivo test was done to know the woven bone, collagen type I, and osteonectin amount formed during the implantation in rabbits for 30 and 60 days. Based on the SEM morphology test, the average pore size in the two groups of samples was 462.15 µm. All scaffolds from this study contain hydroxyapatite’s functional groups matched with literature and are non-toxic after being tested by the MTT assay. These scaffolds could be applied as bone grafts because the percentage of sample degradation is < 30% after 4 weeks and could swell, which would be good for cell adhesion and infiltration during bone healing. The woven bone in the BHA scaffolds and freeze-dried BHA-secretome composite were 371.89 ± 62.09 and 524.69 ± 81.21, respectively. The osteonectin in the composite group was more than in the control group at 30 days in reverse with collagen type 1. The synthesized scaffolds showed good characteristics of bone graft and supported woven bone formation. This composite is suitable for bone graft applications.