Real-time monitoring of the cell agglutination process with a quartz crystal microbalance

The real-time monitoring of the agglutination process of human hepatic normal cells (L-02) at the quartz crystal microbalance (QCM) gold (Au) electrode was performed. Two lectins, concanavalin A (Con A) and wheat germ agglutinin (WGA), induced the cell agglutination, resulting in the different Δf0 and ΔR1 responses from those caused by the normal cell attachment and growth. The cell–Con A–cell aggregates had higher affinity for the Au substrate due to the excellent adsorption ability of Con A, which was revealed by increased Δf0 and ΔR1 shifts and the obvious mass effect of QCM. In contrast, the lower adsorption ability of cell–WGA–cell aggregates was related to the same characteristic of WGA, presenting the decreased Δf0 and ΔR1 responses and the time-extended adhesion phase. Parallel microscopic observation experiments were also carried out and exhibited comparable results. The Δf0 responses during the processes of cell growth and cell agglutination were analyzed using the equations Δf0=a0+a1e-t/τ1+a2e-t/τ2+a3e-t/τ3Δf0=a0+a1e-t/τ1+a2e-t/τ2+a3e-t/τ3 and Δf0=a0+a1e-t/τ1+a2e-t/τ2Δf0=a0+a1e-t/τ1+a2e-t/τ2, respectively. Furthermore, the current work proved that the QCM measurement technique based on cell agglutination was useful for discriminating hepatic normal cells (L-02) and hepatic cancer cells (Bel7402).