Polydioxanone-Based Membranes for Bone Regeneration

Abstract

Resorbable synthetic and natural polymer-based membranes have been extensively studied for guided tissue regeneration. Alloplastic biomaterials are often used for tissue regeneration due to their lower immunoreactivity when compared with allogeneic and xenogeneic materials. Plenum^® Guide is a synthetic membrane material based on polydioxanone (PDO), whose surface morphology closely mimics the extracellular matrix. In this study, Plenum^® Guide was compared with collagen membranes as a barrier material for bone-tissue regeneration in terms of acute and subchronic systemic toxicity. Moreover, characterizations such as morphology, thermal analysis (Tm = 107.35 °C and crystallinity degree = 52.86 ± 2.97 %, final product), swelling (thickness: 0.25 mm ≅ 436% and 0.5 mm ≅ 425% within 24 h), and mechanical tests (E = 30.1 ± 6.25 MPa; σ = 3.92 ± 0.28 MPa; ε = 287.96 ± 34.68%, final product) were performed. The in vivo results revealed that the PDO membranes induced a slightly higher quantity of newly formed bone tissue than the control group (score: treated group = 15, control group = 13) without detectable systemic toxicity (clinical signs and evaluation of the membranes after necropsy did not result in differences between groups, i.e., non-reaction -> tissue-reaction index = 1.3), showing that these synthetic membranes have the essential characteristics for an effective tissue regeneration. Human adipose-derived stem cells (hASCs) were seeded on PDO membranes; results demonstrated efficient cell migration, adhesion, spread, and proliferation, such that there was a slightly better hASC osteogenic differentiation on PDO than on collagen membranes. Hence, Plenum^® Guide membranes are a safe and efficient alternative for resorbable membranes for tissue regeneration.

Keywords: bone regeneration; membrane; polydioxanone; scaffold.

Figure 1

Morphological analysis of the PDO membranes. (a) Fluorescence microscopy using Hoechst dye. SEM images at (b) 200×, (c) 1000×, and (d) 2000× magnification.

Figure 2

Mechanical traction properties. Tensile stress curves as a function of sample elongation, before (a) and after (c) the sterilization process. Mechanical properties in membrane traction, before (b) and after (d) the sterilization process. Test speed: 50 mm/min.

Figure 3

Swelling analysis of the 0.25- and 0.5- mm PDO membranes over time. The percentages were calculated in relation to the dry mass of the membrane.

Figure 4

The hASCs seeded on PDO membranes. Cells were stained with (a) PHK26 and Hoechst solution 4 h after incubation on the membrane, (b) PHK26, and (c) FITC after 24 h of incubation. (d) SEM image of hASCs after 11 days on the membrane.

Figure 5

Osteogenic differentiation on the PDO membrane after incubation for (a,b) 5 and (c,d) 11 days. Osteogenic differentiation on the collagen membrane after incubation for (e,f) 5 and (g,h) 11 days.