Sequence-Prescribed β-Sheet for Enhanced Electron Tunneling: Boosting Interface Recognition and Electrochemical Measurement.

Peptide self-assemblies could leverage their specificity, stability, biocompatibility, and electrochemical activity to create functionalized interfaces for molecular sensing and detection. However, the dynamics within these interfaces are complex, with competing forces, including those maintaining peptide structures, recognizing analytes, and facilitating signal transmission. Such competition could lead to nonspecific interference, compromising the detection sensitivity and accuracy. In this study, a series of peptides with precise structures and controllable electron transfer capabilities were designed. Through examining their stacking patterns, the interplay between the peptides' hierarchical structures, their ability to recognize targets, and their conductivity were clarified. Among these, the EP peptide assembly was identified for its ability to form controllable electronic tunnels facilitated by π-stacking induced β-sheets. EP could enhance the long-range conductivity, minimize nonspecific interference, and exhibit targeted recognition capabilities. Based on EP, an electrochemical sensing interface toward the disease marker PD-L1 (programmed cell death ligand 1) was developed, suitable for both whole blood assay and companion diagnosis. It opens a new avenue for crafting electrochemical detection interfaces with specificity, sensitivity, and compatibility.