Pure titanium and titanium alloy are widely used in oral implant because of their good mechanical properties and biocompatibility, which can be combined with bone tissue to form bone. Studies confirmed that the surface characteristics of titanium and titanium alloy implants affect the rate of bone integration, especially the surface morphology affects the biological behavior and functional status of osteoblasts. At present, the research on implant surface morphology mainly focuses on micron morphology and nano morphology. Studies suggest that micron morphology can enhance mechanical fixation, promote the adhesion and differentiation of osteoblasts and the formation and mineralization of extracellular matrix, change the conformation of protein, promote the orientation, adhesion and proliferation of osteoblasts, and improve the rate of bone integration. However, Meirelles et al. Believe that only nano morphology is not enough to ensure osseointegration, and micron morphology is also very important for osseointegration. Therefore, the implant surface with micro/nano three-dimensional structure will become the trend of future development and research hotspot. In this study, micro-nano 3D morphologies were constructed on pure titanium and titanium alloy using electrolytic etching (EE) to study the different biological behaviors of osteoblasts on the two metal surfaces. The effects of pure titanium and titanium alloy surface on the adhesion, proliferation, cell morphology and activity of alkaline phosphatase (ALP) in osteoblasts were investigated.
The surface characteristics of implants can drive the activity of osteoblasts, especially the microscopic geometry of the surface affects the interaction between implants and osteoblasts, thus guiding subsequent cell reactions. In vitro studies confirmed that the morphology of titanium surface affects the interaction between cells and biomaterials, such as cell attachment, proliferation and differentiation. The attachment and adhesion of cells are related to the integrin receptor, whose subunit (β 1-integrin) is an important adhesion molecule of osteoblasts and plays a key role in the process of cell attachment and extension. When integrin is combined with the extracellular matrix proteins (fibronectin and collagen ⅰ) synthesized by osteoblasts, adhesion spots are formed, and the cytoskeleton and extracellular matrix proteins are bonded together, making cells adhere to the material surface. The adhesion of integrins to matrix proteins activates the signaling system, transmitting surface topography signals into the cell until the nucleus. This signal can regulate cell shape, migration, proliferation, differentiation and gene expression. After cell adhesion, integrin activation not only affects signal transduction and expression of transcription factors, but also affects cytoskeleton structure, thereby affecting cell morphology and elongation. Actin connected with integrin is redistributed and arranged under the drive of surface signals, which drives the cell plasma forward to extend and change the cell morphology . Different surface integrin subunits react and express differently, and their local dynamics are different, resulting in different expression of cell shape, elongation and transcription molecules.
