Micro-BLMs on highly ordered porous silicon substrates: rupture process and lateral mobility.

Area of Science:

• Materials Science
• Biophysics
• Nanotechnology

Background:

• Nano-black lipid membranes (nano-BLMs) exhibit continuous increases in membrane conductance.
• Previous hypotheses suggested independent rupturing of single membranes or membrane patches covering pores.

Purpose of the Study:

• To experimentally validate the hypothesis that membrane conductance increases in nano-BLMs are due to individual membrane ruptures.
• To investigate the formation and properties of micro-BLMs on porous silicon substrates.

Main Methods:

• Preparation of micro-BLMs on porous silicon substrates with gold coating and specific lipid functionalization (DPPTE and DPhPC).
• Investigation using fluorescence microscopy and impedance spectroscopy.
• Fluorescence recovery after photobleaching (FRAP) for lipid diffusion analysis.

Main Results:

• Formation of pore-suspending bilayers with high membrane resistance was confirmed.
• Observed increases in membrane capacitance and conductance were directly linked to individual membrane ruptures.
• Mean effective diffusion coefficient of lipids within micro-BLMs was determined as Deff = (14 ± 1) µm²/s.

Conclusions:

• The study provides unambiguous evidence that increased membrane conductance in these systems arises from the rupturing of individual pore-suspending membranes.
• Micro-BLMs on porous substrates are viable models for studying membrane dynamics and rupture events.
• Lipid lateral mobility in micro-BLMs was quantified, offering insights into membrane fluidity.