Real-time QCM-D monitoring of endothelial cells and macrophages adhering and spreading to SEMA4D/heparin surfaces.

In vitro evaluation techniques that address cellular interactions under dynamic circumstances are required for the development of advanced biomaterials. In this study, quartz crystal microbalance and dissipation (QCM-D) provided a surface sensitive technique that enabled real-time monitoring of the adhesion and spreading response of endothelial cells (ECs) and macrophages (MAs) to soluble-semaphoring 4D (SEMA4D)/heparin modified substratum. The high heparin and low SEMA4D of substratum promoted ECs adhering and spreading. However, surfaces with high SEMA4D and low heparin enhanced MA adhering and spreading. Furthermore, DF plots of QCM-D indicated that the adhering and spreading of MAs were mainly mediated via the ligand-receptor interaction of SEMA4D-CD72, while both adhering and spreading of ECs were mainly mediated via heparin-induced integrin binding. This study suggests that QCM-D combined with other appropriate methods can be utilized to explore the mechanisms for cellular interaction with biomaterial surfaces.