Two-step formation of multilayered membrane pattern from living cells and probing its nanoscale physicochemical properties via nanopipette.

Cell membrane with varied physicochemical properties, e.g., morphology and surface charge, has played crucial roles in many life-related activities. Numerous artificial lipid bilayer membranes (LBM) have been used broadly as model systems to mimic natural cell membrane for studying these properties. However, precisely probing the nanoscale physicochemical properties of natural cell membranes with high resolution and sensitivity remains a key challenge. Here, we present a two-step method, namely, "dipping" and "writing", using nanopipette to create multilayered lipid bilayer membrane (MLBM) derived from cell surface on substrates. During the dipping step, membrane components are adsorbed onto the inner wall of nanopipette, while the writing step enables the controlled deposition of MLBM onto the substrate. Physicochemical characterization reveals that MLBM undergoes dynamic formation, accompanied by frequent variations in membrane size and thickness. Surface charge mapping further demonstrates a heterogeneous charge distribution across the MLBMs, which is distinct from that of the substrate. This heterogeneity is primarily attributed to variations in membrane fluidity and thickness. Moreover, compared to artificial LBM, MLBMs produced via this two-step method allow the use of smaller apertures and higher ion current reduction setpoints, leading to significantly enhanced imaging resolution and detection sensitivity. This work offers a straightforward and efficient strategy for investigating nanoscale physicochemical properties of natural cell membranes. Additionally, the MLBMs serve as a versatile platform for future studies of membrane-related processes, such as biosensing and drug screening.