Enhanced intrinsic biomechanical properties of osteoblastic mineralized tissue on roughened titanium surface

Abstract

The biological mechanisms underlying bone-titanium integration and biomechanical properties of the integrated bone are poorly understood. This study assesses intrinsic biomechanical properties of mineralized tissue cultured on titanium having different surface topographies. The osteoblastic phenotypes associated with mineral deposition and collagen synthesis underlying the biomechanical modulation are also reported. Rat bone marrow-derived osteoblastic cells were cultured either on the machined titanium disc or acid-etched titanium disc. Nano-indentation study of day 28 culture revealed that the mineralized tissue on the acid-etched surface shows 3-3.5 times greater hardness than that on the machined surface (p < 0.01). Elastic modulus of the mineralized tissue was also 2.5-3 times greater on the acid-etched surface than on the machined surface (p < 0.01). After 28 days of culture, mineralized nodule area was significantly lower on the acid-etched surface than on the machined surface (p = 0.0105), while total calcium deposition did not differ between the two surfaces, indicating denser mineral deposition on the acid-etched surface. Osteopontin and osteocalcin gene expressions assayed by the reverse transcriptase-polymerase chain reaction were upregulated in the acid-etched titanium culture. Collagen synthesis measured by Sirius red stain-based colorimetry was 1.5-10 times higher on the acid-etched surface than on the machined surface in the initial culture period of day 1 to day 14 (p < 0.0001). The amount of collagen synthesis corresponded with the enhanced gene expression of prolyl 4-hydroxylase, a key enzyme for post-translational modification of collagen chains. Scanning electron microscopic images revealed that tissue cultured on the acid-etched titanium exhibited plate-like, compact surface morphology, while the tissue on the machined titanium appeared porous and was covered by fibrous and punctate structures. We conclude that culturing osteoblasts on rougher titanium surfaces enhances hardness and elastic modulus of the mineralized tissue, associated with condensed mineralization, accelerated collagen synthesis, and upregulated expression of selected bone-related genes.

Skeletal stem cell and bone implant interactions are enhanced by LASER titanium modification

“…It is assumed this is a consequence of enhanced material surface reactivity [26] and enhanced physical-chemical properties [6]. In contrast, Takeuchi et al showed that a modified surface can reduce cell proliferation whilst initially driving the expression of specific cell markers except for ALP 6 [27]. The cellbiomaterial interface functions not only to define the boundary between tissue and implant, but also to act as a mediator of first stage protein interactions as well as later stage cell adhesion and orientation [28].…”

Three-dimensional finite element analysis of the effects of implant diameter and photofunctionalization on peri-implant stress

“…Hence, a total of 60 models were created for this experiment. Bone surrounding the implant was constructed with cortical bone, as described previously (15,16).…”

Effects of a hybrid micro/nanorod topography-modified titanium implant on adhesion and osteogenic differentiation in rat bone marrow mesenchymal stem cells

“…Pickling in oxalic acid is a method commonly used to pretreat titanium because it can produce samples with microscale surfaces and multifaceted devices with complex three-dimensional shapes, making them superior for practical application. Moreover, this method has been used to treat orthopedic and dental implants because it has the ability to induce distinct osteoblastic functions in vitro 28 and enhance the bone-implant contact. 29 Based on the pretreated microstructures, we fabricated a nanorod structure using hydrothermal hydrogen peroxide treatment.…”