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

•A localized surface plasmon resonance (LSPR) sensor of homogeneous Al nanopyramid array was applied to monitor the adhesion process of cells.•A LSPR sensing mechanism was proposed to reveal the relationship between the LSPR signal and the cell-substrate contact area.•Compared to the microscope-based analysis, this LSPR sensor could study the dynamics in the initial process of cell adhesion more accurately.•The whole LSPR sensing system is simple, which provides a prospect for full-automatic measurement of cell adhesion process.