In this article, we show how SEM and TGA measurements were used to characterize novel osteochondral scaffolding material that can be used as implants for repairing injuries to articular cartilage or for producing biomimetic biological tissue (tissue engineering).
We rely on different types of joints to allow coordinated movement of our limbs and body. In many cases, joints are points at which the ends of two bones are connected; the rounded end of one bone fits into the socket of another bone. The articular cartilage together with the synovial fluid distributes the pressure on the bones uniformly over the entire joint and prevents friction between the bones.
In contrast to skin injuries, injuries to articular cartilage take much longer to heal because articular cartilage exhibits poor healing and self-repair capacity [1].
For this reason, different possibilities are currently being investigated to accelerate the healing process of injuries to articular cartilage through surgical operations. This involves transplanting articular cartilage together with pieces of bone.
It would be much easier if suitable implants were available. Such an implant would have to consist of the bone material and a layer that mimics articular cartilage whereby both layers would have to correspond as closely as possible to the biomechanical properties and structures of the bone and articular cartilage [2]. In recent years, we have developed a process by means of with which we can prepare very homogeneous layers [3].
In this article, we investigate the chemical-physical properties of such layers using scanning electron microscopy (SEM) and thermogravimetry (TGA) and compare our material with material prepared using current standard procedures [4, 5].
The morphological and structural properties of the materials are of special interest.
Preparation of bone-cartilage scaffold material
The subchondral bone-mimicking layer was developed from organic fibers of collagen and chitosan (30/10 wt %) together with a mineral filler (nanocrystalline, magnesium-doped hydroxyapatite, Mg-HA, 60 wt %) embedded in a polymer matrix of 1.4 butanediol diglycidylether (BDDGE, Sigma-Aldrich).
This material is very similar to natural, freshly formed bone material with regard to its structural and mechanical properties...
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SEM measurements performed on cartilaginous and subchondral bone layers prepared using our new technique revealed highly ordered and homogeneous structures with pore sizes in the range 50 to 400 μm. This makes the material very suitable as a scaffold for the production of synthetic biological tissue.
The TGA measurements confirmed the SEM results that the process we have developed makes it possible to prepare chemically stable, homogeneous biomimetic structures based on collagen/chitosan fibers and lamellas, in which Mg-HA can be additionally incorporated, depending on the desired use.
Comparison measurements of materials made by conventional techniques (physical blending of the components) showed that our new wet-chemical process produces considerably more homogeneous and hence more stable structures. The innovative process guarantees the production of a biomimetic scaffold with an excellent morphological and biological structure and a composition analogous to that of the native extra-cellular matrix of osteochondral tissue. This makes it an ideal candidate for tissue engineering or in-situ osteochondral regeneration.
Chemical-Physical Properties of a Novel Biphasic Biomimetic Scaffold for Tissue Regeneration | Thermal Analysis Application No. UC365 | Application published in METTLER TOLEDO Thermal Analysis UserCom 36