Cell Adhesion Characteristics on Tantalum Pentoxide Gate Insulator for Cultured-Cell-Gate Field-Effect Transistor

Understanding the interaction between living cells and a tantalum pentoxide (Ta₂O₅) gate electrode is important for controlling cell adhesion and functions when developing a cultured-cell-gate field-effect transistor biosensor. In this study, we evaluate the cell adhesion characteristics of the Ta₂O₅ membrane without or with a polydopamine (pDA) coating for chondrocytes, which is expected as a treatment for improving biocompatibility. As a result, the native and pDA-modified Ta₂O₅ membranes are shown to have the appropriate surface tension (35-40 dyn/cm) for the adhesion of chondrocytes owing to the contribution of surface tension to not only the nonspecific adsorption of serum proteins as the scaffold of chondrocytes but also the maintenance of the conformation of serum proteins. In particular, the serum proteins adhere more efficiently to the native Ta₂O₅ membrane than to the pDA-modified ones owing to the relatively smaller surface tension of the native Ta₂O₅ membrane; as a result, the proliferation and production of extracellular matrix (ECM) proteins such as collagen and proteoglycans by chondrocytes are clearly enhanced on the native Ta₂O₅ membrane. Thus, the native Ta₂O₅ membrane shows superior performance for the chondrocyte culture on it compared with the pDA-modified ones.