The Role of Fetuin-A on the Attachment and Proliferation of Osteoblast-like Cells on Model Gold Surfaces

Fetuin-A is a plasma protein of interest for bone-interfacing applications due to its role in mineralization processes through calcium/phosphate ion-binding capabilities. However, the role of fetuin-A in the initial stages of cellular interaction with biomaterials and the mechanisms involved are not fully clear. This work investigated the response of osteoblast-like Saos-2 cells to model gold substrates presenting pre-adsorbed fetuin-A as a surface modification, to determine the role of the protein in cell attachment and proliferation. Correlative quartz crystal microbalance with dissipation (QCM-D), surface plasmon resonance, and radiolabeling confirmed fetuin-A adsorbed on model surfaces in similar quantities compared to serum albumin but formed a less packed layer with increased water entrapment. Surfaces presenting pre-adsorbed fetuin-A enhanced cellular adhesion, similar to fibronectin, but attached cells displayed morphological characteristics more similar to those with pre-adsorbed albumin, with lower average surface area and maximum axis. Over 3 days, fetuin-A exhibited lower cellular proliferation compared to the fibronectin control, likely correlated to the decrease in cellular metabolism observed at the same time-point, and persisted over 7 days. These results provide insight into the role of adsorbed fetuin-A for bone-interfacing implant applications, suggesting the pre-adsorption of the protein alone aids cellular attachment, but is not sufficient to promote early stages of osseointegration.