A Comprehensive Microstructural and Compositional Characterization of Allogenic and Xenogenic Bone: Application to Bone Grafts and Nanostructured Biomimetic Coatings

Abstract

Bone grafts and bone-based materials are widely used in orthopedic surgery. However, the selection of the bone type to be used is more focused on the biological properties of bone sources than physico-chemical ones. Moreover, although biogenic sources are increasingly used for deposition of biomimetic nanostructured coatings, the influence of specific precursors used on coating’s morphology and composition has not yet been explored. Therefore, in order to fill this gap, we provided a detailed characterization of the properties of the mineral phase of the most used bone sources for allografts, xenografts and coating deposition protocols, not currently available. To this aim, several bone apatite precursors are compared in terms of composition and morphology. Significant differences are assessed for the magnesium content between female and male human donors, and in terms of Ca/P ratio, magnesium content and carbonate substitution between human bone and different animal bone sources. Prospectively, based on these data, bone from different sources can be used to obtain bone grafts having slightly different properties, depending on the clinical need. Likewise, the suitability of coating-based biomimetic films for specific clinical musculoskeletal application may depend on the type of apatite precursor used, being differently able to tune surface morphology and nanostructuration, as shown in the proof of concepts of thin film manufacturing here presented.

An Observational Prospective Clinical Study for the Evaluation of a Collagen-Hydroxyapatite Composite Scaffold in Hip Revision Surgery

“…However, their use relies on sophisticated bone banking systems, which work under stringent guidelines to avoid potential disease transmission or other issues mainly associated with tissue collection, processing, preservation, and storage. Therefore, based on the biomimetic principle, although a material as similar as possible to the host bone is recommended to allow the best biological behaviour [ 48 ], relative concerns over the use of autografts or allografts have led to the development of numerous synthetic bone graft substitutes. In this regard, several commercial bone substitutes have been demonstrated to restore bone loss and withstand the dynamics of compaction [ 12 ], while having advantages such as an unlimited supply, easy sterilisation, and room temperature storage [ 49 ].…”

Custom Massive Allograft in a Case of Pelvic Bone Tumour: Simulation of Processing with Computerised Numerical Control vs. Robotic Machining

“…Consequently, it is not easy adapting such machines to the strict requirements of cleanroom environments. Therefore, the use of standard CNC machines for the processing of bone allografts requires the application of less stringent cleaning standards, with the consequent need for final sterilization, which affects the chemical and biomechanical properties of tissues [ 50 , 51 , 52 ]. Thus, it is mandatory to develop custom CNC machines suitable for controlled contamination environments to avoid the abovementioned critical issues.…”

Poly-ε-Caprolactone/Fibrin-Alginate Scaffold: A New Pro-Angiogenic Composite Biomaterial for the Treatment of Bone Defects

“…Xenogenic bone is another source of bone tissue with both osteoconductive and osteoinductive properties. However, a graft as similar as possible to the host bone in terms of microstructure and composition is recommended for optimum biological behaviour and clinical performance [ 2 ]. Implants made of metals such as titanium and stainless steel are also used to treat bone defects; however, they have a limited lifespan and cause stress shielding due to excessive material strength [ 3 ].…”