Plasmonic Al nanopyramid array sensor for monitoring the attaching and spreading of cells

A strategy for monitoring the dynamics of cell adhesion is reported based on localized surface plasmon resonance (LSPR) sensor, which consists of homogenous plasmonic Al nanopyramid array (NPA). The subtle change of cell-substrate interface could be detected since the LSPR sensor can response to the refractive index changes in the vicinity of its surface. We simulated the extinction spectra of homogenous Al NPA biosensor during cell adhesion, and obtained a linear relationship between the LSPR peak shifts and the changes in cell-substrate contact area. On the basis of this mechanism, we applied an Al NPA sensor to monitor the adhesion process of bone mesenchymal stem cells (BMSCs). We attained a dynamic curve of BMSCs adhesion based on the time-dependent LSPR peak shift. Different stages have been identified by the velocity variation of the peak shift, as attaching, fast-spreading, low-spreading and balancing, respectively. Compared to image analysis based on microscope, this LSPR biosensing strategy based on Al NPA shows higher accuracy in monitoring the initial process of cell adhesion. This LSPR biosensor based on homogeneous Al NPA is promising to achieve real-time, semi-quantitative and full-automatic monitoring of cell adhesion process, and can be applied in multiple fields such as cytopathology, oncology and regenerative medicine.