Mechanistic Insights into Unary Peptide–Membrane Interactions Enable Stable Encapsulation and Trigger-Responsive Peptidyl Liposomes

Efforts to engineer trigger-responsive peptidyl liposomes have historically been limited by premature release following peptide conjugation, reflecting an incomplete understanding of tethered peptide–membrane interactions. Here, we establish a unified mechanistic framework for designing encapsulation-stable yet trigger-responsive liposomes by elucidating how membrane-anchored peptides interact with membranes. Screening identified MAG2 as, thus far, the only AMP backbone that can be surface-masked without liposome leakage while preserving latent lytic activity─-an outcome previously unattainable in unary peptidyl liposome systems. Cryo-EM/cryo-ET, SAXS, CD, FLIM/fluorescence imaging, and MTT assays collectively unveil a hierarchical cascade of molecular events: masked peptide–membrane conjugation with stable liposome encapsulation, lateral-diffusion-driven outer leaflet PEG-layer expansion, trigger-induced peptide unmasking, aggregation-mediated membrane defect formation, and outer leaflet PEG-layer collapse, culminating in liposomal content release, intracellular distribution, and trigger-induced cell-killing efficacy. These findings uncover a unary peptide–membrane interaction mechanism that will redefine the design principles of trigger-responsive therapeutic peptidyl liposomes. This publication is licensed under You are free to share (copy and redistribute) this article in any medium or format and to adapt (remix, transform, and build upon) the material for any purpose, even commercially within the parameters below: Creative Commons (CC): This is a Creative Commons license. Attribution (BY): Credit must be given to the creator. *Disclaimer This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials. You are free to share (copy and redistribute) this article in any medium or format and to adapt (remix, transform, and build upon) the material for any purpose, even commercially within the parameters below: Creative Commons (CC): This is a Creative Commons license. Attribution (BY): Credit must be given to the creator. *Disclaimer This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials. You are free to share (copy and redistribute) this article in any medium or format and to adapt (remix, transform, and build upon) the material for any purpose, even commercially within the parameters below: Creative Commons (CC): This is a Creative Commons license. Attribution (BY): Credit must be given to the creator. *Disclaimer This summary highlights only some of the key features and terms of the actual license. It is not a license and has no legal value. Carefully review the actual license before using these materials.