Increased Internal Porosity and Surface Area of Hydroxyapatite Accelerates Healing and Compensates for Low Bone Marrow Mesenchymal Stem Cell Concentrations in Critically-Sized Bone Defects

Abstract

Featured Application: Volume and rate of tissue regeneration may be enhanced with increased scaffold porosity as well as increased numbers of non-cultured bone marrow cells. Abstract:For clinical treatment of skeletal defects, osteoinductive scaffolds must have the ability to conform to the unique geometry of the injury site without sacrificing biologically favorable properties, including porosity. This investigation seeks to combine the osteoinductive properties of porous hydroxyapatite (HA) scaffolds with the beneficial handling characteristics of granules or putties, while evaluating the effects of mesenchymal stem cell (MSC) concentration on the composite grafts' ability to regenerate bone in vivo. The results demonstrate that porous HA granules regenerate significantly larger volumes of bone compared to non-porous HA. Increased MSC concentrations in autologous bone marrow aspirate (BMA) contributed to greater bone regeneration. This effect was most predominant with non-porous HA. While the extent of bone regeneration using non-porous HA was strongly correlated with MSC concentration of the marrow, porous HA microparticles combined with autologous BMA were successful in faster treatment of critically-sized bone defects and with less dependence on the MSC concentration than non-porous HA.

Otoliths-composed gelatin/sodium alginate scaffolds for bone regeneration

“…The percentage of otolith grinding retention in the sieve was 0.4%, with 99.6% of particles with a particle size ≤ 45 μm, which is consistent with a very homogeneous granulometric behavior. It is likely that the large surface area of the otolith microparticles could promote fast dissolution due to the greater surface area exposed to the biological environment, allowing the chemical interaction between the biomaterial and the new formed bone, and accelerate the formation and the growth of the biologically active apatite layer [14]. Furthermore, recent reports have suggested that larger sized hydroxyapatite particles (20-100 μm) generate a less prolonged inflammatory response compared with smaller ones, which suggest that incorporation of larger sized particles into biomaterials scaffolds might prove beneficial in promoting a tissue regenerative microenvironment upon implantation [15].…”

Synthesis and characterization of biomimetic bioceramic nanoparticles with optimized physicochemical properties for bone tissue engineering

“…35,36 Therefore, many efforts have been made to minimize the amorphous content and increase the crystallinity ratio especially for HA coating of implant materials which is reported to improve the integration and survivorship of biomaterials within a living system. For example, nHA with high crystallinity has been reported to exhibit a lower degradation rate, a higher shear strength, a more stable bone integration, and to accelerate bone healing in critical size defects.…”

“…For example, nHA with high crystallinity has been reported to exhibit a lower degradation rate, a higher shear strength, a more stable bone integration, and to accelerate bone healing in critical size defects. 35,36 Therefore, many efforts have been made to minimize the amorphous content and increase the crystallinity ratio especially for HA coating of implant materials which is reported to improve the integration and survivorship of biomaterials within a living system. 35,37 For this purpose, milling time was one of the selected processing variables in this study to modify the crystallinity ratio.…”

Electrical Stimulation through Conductive Substrate to Enhance Osteo-Differentiation of Human Dental Pulp-Derived Stem Cells

“…For treatment of skeletal defects, osteo-conductive materials are critical to promote bone healing [34]. To determine whether PPy is a suitable substrate for cell culture in vitro, hDPSCs were seeded on PPy films.…”