Figure 1

AuNPs attached onto silicon substrate using chemical functional group. Schematic illustration of the AuNP-coating procedure on the Si substrate and characterization regimes for the chemical interaction between AuNPs and chemical functional groups. (I) AuNPs immobilized on aminated surface (AuNP-S_A); (II) AuNPs immobilized on catecholic surface (AuNP-S_D) functionalized with dopamine (DOPA). Each sample is quantitatively characterized by experimental toolkits such as cantilever bioassay, PeakForce QNM, as well as lateral force microscopy (LFM).