The biological responses of osteoblasts on titanium: Effect of oxygen level and surface roughness

Background/Purpose: Due to the general application of in vitro test, cell culture is generally selected to evaluate the cytocompatibility of devices and materials. The choice of test condi-tion should depend on the probable site and clinical application. The oxygen content of human body could be estimated around 5%w12%, and the oxygen level of healing bone fracture range from 0.8%w3.8%%. However, materials for bone implant are traditionally evaluated under lab-oratory normoxia condition (21% O2) in vitro. The aim was to study the effect of oxygen level on osteoblast upon high stiffness titanium with different roughness.Methods: After sandblasted and acid-etched (SLA) process, we create titanium surfaces with four different roughness. The differentiation and proliferation of MC3T3-E1 osteoblast cultured on SLA-treated specimens were evaluated in designed chamber with oxygen level of 1%, 5%, 10%, 21%.Results: By scanning electron microscopy, all samples had sub-micro pit inside the micro-holes upon SLA-treated Ti disk surface. The decrease of oxygen level from 21% to 5% promoted oste-oblast growth of SLA-treated specimens, but 1% O2 delayed cell proliferation. The surface roughness of specimens influenced osteoblast cell differentiation. The differentiation and pro-liferation ability of the cells upon SLA-treated specimens is proportional to oxygen level. Conclusion: Our results demonstrated that 5% O2 will easily discriminate osteoblasts responses on different SLA-treated specimens. These results suggest that hypoxia (5% O2) environment is better model for biological evaluation of bone-related materials.Copyright & COPY; 2023, Formosan Medical Association. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).