Fig. 1. (a) Preparing SAMs with different terminal chemical groups for OPN adsorption and cell adhesion studies: (a1) chemical groups (–OH, –OEG, –COOH, –NH₂, and –PO₃H₂) were first self-assembled on a gold slide; (a2) then OPN was adsorbed on the SAMs; and (a3) MSCs were finally seeded and adhered on these SAMs. (b) Surface wettability and (c) surface zeta potential data from the obtained SAMs. The stars in (b) indicate significant difference (p < 0.05).