Osteosphere Model to Evaluate Cell–Surface Interactions of Implantable Biomaterials

Abstract

Successful biomaterials for bone tissue therapy must present different biocompatible properties, such as the ability to stimulate the migration and proliferation of osteogenic cells on the implantable surface, to increase attachment and avoid the risks of implant movement after surgery. The present work investigates the applicability of a three-dimensional (3D) model of bone cells (osteospheres) in the evaluation of osteoconductive properties of different implant surfaces. Three different titanium surface treatments were tested: machined (MA), sandblasting and acid etching (BE), and Hydroxyapatite coating by plasma spray (PSHA). The surfaces were characterized by Scanning Electron Microscopy (SEM) and atomic force microscopy (AFM), confirming that they present very distinct roughness. After seeding the osteospheres, cell–surface interactions were studied in relation to cell proliferation, migration, and spreading. The results show that BE surfaces present higher densities of cells, leaving the aggregates towards than titanium surfaces, providing more evidence of migration. The PSHA surface presented the lowest performance in all analyses. The results indicate that the 3D model allows the focal analysis of an in vitro cell/surfaces interaction of cells and surfaces. Moreover, by demonstrating the agreement with the clinical data observed in the literature, they suggest a potential use as a predictive preclinical tool for investigating osteoconductive properties of novel biomaterials for bone therapy.

Optimization of a Tricalcium Phosphate-Based Bone Model Using Cell-Sheet Technology to Simulate Bone Disorders

“…In vitro bone models are used to mimic native cortical or trabecular bone to study physiological processes (e.g., metabolism of bone turnover), pathophysiological processes (e.g., cellular processes in bone healing), the effects of agents on bone homeostasis and regeneration (e.g., glucocorticoids or BMPs), implant integration (e.g., the interaction of bone and implant surfaces), or the suitability of the model as an implant itself (e.g., load-bearing capacity and stability) [2]. To evaluate substances or implant materials (evaluation of osteoconductive properties) in high-throughput format about toxicology, biocompatibility, tolerability, and osteoinductivity, simple, easy-to-handle scaffold-free spheroid cultures (osteospheres) with a 3D architecture but without mechanical strength are used [74][75][76][77][78][79]. In contrast, scaffold-or hydrogel-based models own load-bearing capacity and the option for a trabecular-like structure [80][81][82][83][84][85][86][87].…”