Giant cells and osteoclasts present in bone grafted with nacre differ by nuclear cytometry evaluated by texture analysis

Monocyte Differentiation on Atomic Layer-Deposited (ALD) Hydroxyapatite Coating on Titanium Substrate

Hydroxyapatite (HA; Ca₁₀(PO₄)₆(OH)₂) coating of bone implants has many beneficial properties as it improves osseointegration and eventually becomes degraded and replaced with new bone. We prepared HA coating on a titanium substrate with atomic layer deposition (ALD) and compared monocyte differentiation and material resorption between ALD-HA and bone. After stimulation with macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor kappa-B ligand (RANKL), human peripheral blood monocytes differentiated into resorbing osteoclasts on bovine bone, but non-resorbing foreign body cells were observed on ALD-HA. The analysis of the topography of ALD-HA and bone showed no differences in wettability (water contact angle on ALD-HA 86.2° vs. 86.7° on the bone), but the surface roughness of ALD-HA (Ra 0.713 µm) was significantly lower compared to bone (Ra 2.30 µm). The cellular reaction observed on ALD-HA might be a consequence of the topographical properties of the coating. The absence of resorptive osteoclasts on ALD-HA might indicate inhibition of their differentiation or the need to modify the coating to induce osteoclast differentiation.

Preclinical safety study of nacre powder in an intraosseous sheep model

Objectives

The purpose of this preclinical study was to evaluate the safety, the local tissue effects and bone healing performance (osteoconduction, osseointegration) of nacre powder in a sheep intraosseous implantation model. This represents the first preclinical study to assess nacre safety and efficacy in supporting new bone formation in accordance with the ISO 10993 standard for biomedical devices.

Methods

The local tissue effects and the material performance were evaluated 8 weeks after implantation by qualitative macroscopic observation and qualitative as well as semiquantitative microscopic analyses of the bone sites. Histopathological characterisations were run to assess local tissue effects. In addition, microarchitectural, histomorphometric and histological characterisations were used to evaluate the effects of the implanted material.

Results

Nacre powder was shown to cause a moderate inflammatory response in the site where it was implanted compared with the sites left empty. The biomaterial implanted within the generated defects was almost entirely degraded over the investigated time span and resulted in the formation of new bone with a seamless connection with the surrounding tissue. On the contrary, in the empty defects, the formation of a thick compact band of sclerotic bone was observed by both microarchitectural and histological characterisation.

Conclusions

Nacre powder was confirmed to be a safe biomaterial for bone regeneration applications in vivo, while supporting bone formation.

Pearl Powder-An Emerging Material for Biomedical Applications: A Review

Pearl powder is a well-known traditional Chinese medicine for a variety of indications from beauty care to healthcare. While used for over a thousand years, there has yet to be an in-depth understanding and review in this area. The use of pearl powder is particularly growing in the biomedical area with various benefits reported due to the active ingredients within the pearl matrix itself. In this review, we focus on the emerging biomedical applications of pearl powder, touching on applications of pearl powder in wound healing, bone repairing, treatment of skin conditions, and other health indications.