Membrane formation process

 

This page presents membrane capacitance during formation process. Record of capacitance was start directly after place of drop of forming solution into the hole. In the first stage the capacitance is low, the membrane is thick (several micrometers). Next stage is a fast increase of capacitance - bilayer is established and their area inreases. Last stage is further slow increase of capacitance. After a time the capacitance is stable - the membrane is ready for experiments. The results are obtained using KSP measurement system with software for recording membrane capacitance Membrane formation.
 
The membrane made of lecithin and cholesterol 7:3 dissolved in n-decane (20 mg/ml), electrolyte 0.1M KCl. The formation process is right and obtained membrane is stable. 
The membrane made of lecithin and cholesterol 3:2 dissolved in n-decane (20 mg/ml), electrolyte 0.1M KCl. This membrane was formed much faster than previous one.
The membrane made of lecithin dissolved in n-decane, concentration 20 mg/ml, electrolyte 0.1M KCl. Time of formation of this membrane is much long. Shorter time is more desirable.
The membrane made of lecithin dissolved in n-decane, concentration 20 mg/ml, electrolyte 0.1M KCl. The process of membrane formation is not stable and membrane has low and not stable capacitance. The bilayer occupies small part of the hole, Plateau-Gibbs border is large. This membrane is not useful for further experiments.
The membrane made of mixture of phosphatidylcholine, phosphatidylethanolamine, and cholesterol 3:1:1 dissolved in n-decane, lipid concentration 20 mg/ml, electrolyte: 0.1M KCl, 10mM HEPES, pH 7.0. This membrane has long time of formation and is not stable.
The mambrane made of phosphatidylcholine and suspension of steroid dimer, 20 mg/ml, electrolyte 0.1M KCl. The formation process is fast and obtained membrane is stable.