A polygonal scaffold includes at least three polyproline II (PPII) helix rods and at least three connectors. Each of the PPII helix rods is composed of a plurality of repeat units represented by Formula (i), and at least one of the PPII helix rods has at least one of hydrogen atoms of at least one of the repeat units being substituted by a first chemical handle for connecting a ligand. Each of the connectors is a divalent organic group, and every two of the PPII helix rods are connected by one of the connectors to form a closed ring. |