Abstract

The stability and dynamics of biological membranes are fundamentally governed by their mechanical properties, particularly in the context of pore formation, which is critical for processes like electroporation, drug delivery, and cell death. This study investigates the **line tension** at the edge of a nascent pore within a lipid bilayer membrane supported on a solid substrate. The presence of a solid support introduces complex interactions that can significantly alter the membrane's mechanical response compared to free-standing bilayers. Using a combination of theoretical modeling and advanced simulation techniques, we quantify the line tension, a key parameter determining the energy barrier for pore expansion or closure. Our results demonstrate that the solid support-membrane interface, characterized by specific adhesion and friction forces, leads to a measurable increase in the effective line tension. This increase is dependent on the substrate's rigidity and the hydration layer thickness. Furthermore, we show that the calculated line tension is highly sensitive to the pore radius, suggesting a non-linear energy landscape for pore evolution. These findings provide crucial quantitative insights into the biophysics of supported lipid bilayers, which are widely used as model systems, and have direct implications for understanding membrane rupture and repair mechanisms in cellular environments.