Patent ID: 8476065

Claim:
A device comprising: (a) a substrate having a surface; and (b) regions on the surface, each region separately comprising an ordered, two-dimensional array of post sets over the surface, wherein the pitch between adjacent posts within each post set of a region is uniform and is less than about 100 nm, and wherein each post has affixed thereto a ligand or protein molecule that comprises at least a portion of a full-length tubulin; but the device comprises a gradient of pitch values from one region to another, designed for measuring the spatial dependence of binding of one analyte molecule to a post set within at least one region; wherein the pitch is the distance between center points of adjacent posts in a post set and the gradient is a gradual change in the pitch values in the different regions such that the distance between posts in a post set in at least one region matches the spacing and distribution of binding sites in a complex that forms between the one analyte molecule and two ligands or protein molecules on different posts within a post set.