Probing the influence of tether density on tethered bilayer lipid membrane (tBLM)-peptide interactions

Abstract Tethered bilayer lipid membranes (tBLMs) represent a promising model membrane system that can host transmembrane proteins to serve as biosensors with exceptional detection performance. Herein, using the quartz crystal microbalance-dissipation (QCM-D) technique, we systematically investigated the influence of tether density on tBLM-peptide interactions and characterized the membrane binding dynamics of membrane-active peptides on tBLMs using AH peptide as a model. To achieve both physical stability and nanoscale separation from the support substrate, the tBLMs were fabricated on self-assembled monolayers (SAMs) obtained using a mixture of tether and spacer molecules with controlled tether-to-spacer ratio from 1:99 (T1) to 100:0 (T100). The solvent-assisted lipid bilayer (SALB) formation method was then employed to form the tBLMs, before the introduction of AH peptide. The QCM-D measurement responses indicated that the interactions between AH peptide and tBLMs involved peptide adsorption on the membrane layer followed by peptide translocation across the membrane. With increasing tether density, the abundance of hydrophobic groups within the tether chain led to stronger interactions and greater amount of translocated peptide. Depending on the tether density, this could result in significant structural transformation within the tBLM. Taken together, our work highlights the prospect of modulating membrane-peptide interactions by means of controlling the tBLM architecture, which will facilitate the creation of model membrane systems with highly tailored functionalities.