π-π Stacking Network-Based Supramolecular Peptide Nanoprobe for Visualization of the ICB-Enhanced Ferroptosis Process.

The construction of coassembled peptide nanoprobes based on structural adaptation provides an effective template for stable monitoring of the molecular events in physiological and pathological processes. This also greatly expands their applications in biomedicine, such as multimodal combined diagnosis and treatment. However, the insufficient understanding of the physicochemical properties and structural features of different molecules still makes it difficult to construct the coassembled probes with mutually reinforcing functions, leading to unpredictable effects. Here, we showed how to utilize the π-π stacking network on ß-sheets formed by PD-L1-targeting peptides to capture small molecules with ferroptosis functions, thus, coassembling them into a visual probe with synergistic effects. Compared with individual components, the coassembled strategy could significantly improve the stability of the nanoprobe, inducing stronger ferroptosis effects and immune checkpoint blocking effects, and track and reflect the process. This study provides new insights into the design of multicomponent collaborative coassembly systems with biological effects.

Sequence-Prescribed ß-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 EP5 peptide assembly was identified for its ability to form controllable electronic tunnels facilitated by π-stacking induced ß-sheets. EP5 could enhance the long-range conductivity, minimize nonspecific interference, and exhibit targeted recognition capabilities. Based on EP5, an electrochemical sensing interface toward the disease marker PD-L1 (programmed cell death ligand 1) was developed, suitable for both whole blood assay and in vivo companion diagnosis. It opens a new avenue for crafting electrochemical detection interfaces with specificity, sensitivity, and compatibility.