Balancing Purification and Ultrastructure of Naturally Derived Bone Blocks for Bone Regeneration: Report of the Purification Effort of Two Bone Blocks

Abstract

The present publication reports the purification effort of two natural bone blocks, that is, an allogeneic bone block (maxgraft®, botiss biomaterials GmbH, Zossen, Germany) and a xenogeneic block (SMARTBONE®, IBI S.A., Mezzovico-Vira, Switzerland) in addition to previously published results based on histology. Furthermore, specialized scanning electron microscopy (SEM) and in vitro analyses (XTT, BrdU, LDH) for testing of the cytocompatibility based on ISO 10993-5/-12 have been conducted. The microscopic analyses showed that both bone blocks possess a trabecular structure with a lamellar subarrangement. In the case of the xenogeneic bone block, only minor remnants of collagenous structures were found, while in contrast high amounts of collagen were found associated with the allogeneic bone matrix. Furthermore, only island-like remnants of the polymer coating in case of the xenogeneic bone substitute seemed to be detectable. Finally, no remaining cells or cellular remnants were found in both bone blocks. The in vitro analyses showed that both bone blocks are biocompatible. Altogether, the purification level of both bone blocks seems to be favorable for bone tissue regeneration without the risk for inflammatory responses or graft rejection. Moreover, the analysis of the maxgraft® bone block showed that the underlying purification process allows for preserving not only the calcified bone matrix but also high amounts of the intertrabecular collagen matrix.

In Vivo Analysis of the Biocompatibility and Immune Response of Jellyfish Collagen Scaffolds and its Suitability for Bone Regeneration

“…Three slides of every tissue explant were used for histochemical staining (Hematoxylin and Eosin (H&E), Movat's pentachrome and Masson's trichrome). The staining was performed following previously described methods [44,45,83].…”

Cellular Response of Human Osteoblasts to Different Presentations of Deproteinized Bovine Bone

“…Biomaterial purification has been an issue in the field of bone substitute materials since its conception [20]. Non-autologous bone substitutes from different origins, either from same species donors (allografts) or different species (xenografts), carry the potential of disease transmission or even the induction of an adverse immunological reaction [9,16,21]. These materials can contain bacteria, viruses, antigens, immunological molecules, and proteins that ideally should be eliminated or inactivated by standardized procedures before clinical application [8,16,22,23].…”

“…Most available bone substitute materials contain some degree of impurity, and it is not clear how these features interfere with the biocompatibility and bone formation. Inflammatory foreign body reaction is a current concern regarding the use of biomaterials for bone augmentation, and the pattern of macrophage reaction seems to be an important marker to predict if a biomaterial becomes successfully incorporated into host bone and allows new bone formation, or if it may undergo complete encapsulation [9,13,29,30].…”

“…Bone substitute materials should accomplish a series of requirements to be suitable for clinical use. In addition to advantageous properties such as osteoconductivity or osteoinductivity of a material, biocompatibility is one of the most important requirements [9][10][11][12].…”

Clinical and laboratorial outcomes of xenogeneic biomaterials: literature review

“…The first methods of purification consisted in simple mechanical fragmenting and physical exposition to low temperatures, as boiling or dry oven. This process removes the macro and visible organic constituents of animal bone, but not the collagen proteins which compound the bone matrix, or the cellular constituent (48,54,55).…”