Before total synthesis, we conducted computational chemistry to obtain the size of all designed model analytes. The computational results indicated that the smallest structure MN1 with a minimum epitope distance of 2.4 Å had been obtained, and the epitope distances of the model analytes gradually increased to reach a maximum of 19.0 Å for the largest structure MN9 (Fig. ). It was observed that the sizes of most model analytes in the study were inferior to those that had been assayed by sandwich immunoassay (Supplementary Table ). The detailed synthesis and characterization of the model analytes and haptens are provided in the Supplementary Information (Supplementary Figs. and).