Bioactivation of Bovine Bone Matrix and Collagen Scaffold Using Argon Plasma: In Vitro Study

Purpose: Bone graft materials and soft tissue allografts are widely used in clinical practice to counteract physiologic postextraction site tridimensional shrinkage. The aim of this study was to test if plasma of argon treatment could have a bioactivation effect on hard and soft tissue scaffolds in clinical usage. Materials and Methods: Forty- eight bovine bone matrix and porcine collagen samples were subdivided into two groups (test and control) of 12 samples each. The test group was treated with argon plasma (10 W, 1 bar for 12 minutes), while the control group was left untreated. Immediate cell adhesion and a proliferation assay at 72 hours were performed in the perfusion chamber of a bioreactor. Additionally, micro- CT analysis was performed on the treated and untreated scaffolds, before and after soaking in cell culture medium (four samples). Results: Osteoblasts seeded on plasma-treated bone matrix significantly increased the adhesion level compared with the untreated sample (43,144.3 +/- 12,442.9 vs 21,736 +/- 77,27.1; P = .0083). However, 3-day proliferation tests could not achieve significant differences between groups (105,715.5 +/- 21,751.5 vs 107,108.6 +/- 19,343.4; P = .998). No differences were measured on fibroblast adhesion on the collagen matrix in both conditions. Plasma of argon treatment and soaking in cell culture medium did not affect the bone matrix samples. The structure of collagen matrix samples was unaltered after plasma treatment, but became enlarged after soaking. Conclusion: Plasma of argon may be useful to biofunctionalize bone grafts, although benefits seemed to disappear after 3 days. No biologic response was detected on collagen matrix scaffolds. In vivo studies are needed to draw final clinical conclusions.