Quartz Crystal Microbalance Analysis of Antimicrobial Protein Adsorption onto Zirconia

Protein adsorption on dental zirconia (ZrO₂) surfaces plays a crucial role in plaque formation, tissue healing, and bone osseointegration. This study investigated and compared the adsorption behavior of three salivary antimicrobial proteins—peroxidase, lactoferrin, and lysozyme—on a ZrO₂ sensor and an Au sensor using a quartz crystal microbalance (QCM) operating at 27 MHz. Protein adsorption was determined from frequency decreases, and the apparent reaction rate constant (k_obs) was calculated by fitting frequency–time curves to a kinetic model. The amount of lactoferrin adsorbed on the ZrO₂ sensor was significantly higher than that of peroxidase and lysozyme (p < 0.05). Significantly smaller amounts of peroxidase and lysozyme were adsorbed onto the ZrO₂ sensor than the Au sensor (p < 0.05). The k_obs for lysozyme on the Au sensor was significantly higher than those for lactoferrin on sensors and for peroxidase on the Au sensor (p < 0.05). Differences in salivary antimicrobial protein adsorption between Au and ZrO₂ surfaces were influenced, in part, by electrostatic interactions between the proteins and the material surface.