Direct attachment of suspension cells to PDA surface and its application in suspension-cell QCM biosensor

Abstract

Mussel-inspired polydopamine (PDA) has been widely applied for functionalizing various material surfaces through a simple and versatile approach. Several studies have demonstrated the adhesion-promotion properties of the PDA surface for adherent cells. However, few reports are associated with suspension cells. In this study, the attachment property of suspension cells on the PDA surface was investigated for the first time, where we found that the suspension cells can be directly attached to the PDA coating without any secondary modifications. To exemplify the potential of this property, a PDA-based suspension-cell QCM biosensor was fabricated. The biosensor showed a high degree of repeatability and stability as well as low nonspecific binding to the irrelevant protein. The real-time and label-free evaluation of the binding of a diverse range of lectins on three different types of suspension cells indicated the variation of the glycosylation on these cell surfaces. Furthermore, the kinetic evaluation of the protein-carbohydrate interactions on the suspension cell surface was also performed. This work reports a new strategy for fabrication of PDA-based suspension-cell QCM biosensor via simple and efficient immobilization of suspension cells, which provides a simple way for the study of the complex molecular recognition on suspension cell surfaces.