Planar lipid bilayers containing gramicidin A as a molecular sensing system based on an integrated current

Area of Science:

• Biophysics
• Membrane Biophysics
• Biosensing

Background:

• Gramicidin A channels are crucial for studying ion transport across lipid bilayers.
• Lipid bilayer properties, such as head group charge and tail length, influence gramicidin A channel activity.
• Developing sensitive biosensing platforms is essential for detecting biomolecules like bovine serum albumin (BSA).

Purpose of the Study:

• To analyze gramicidin A channel activity in lipid bilayers with varying compositions.
• To engineer an antigen (BSA)-sensitive interface for biosensing applications.
• To evaluate the sensitivity and selectivity of the developed biosensing system for BSA detection.

Main Methods:

• Analysis of gramicidin A channel activity by measuring conductance, event lifetime, and integrated currents.
• Modification of lipid bilayers using phosphatidylethanolamine (PE) and amine coupling.
• In situ coupling of anti-BSA antibodies to the lipid bilayer to create an antigen-sensitive interface.
• Detection of BSA using integrated current as an analytical signal.

Main Results:

• Gramicidin A channel activity is tunable by adjusting lipid bilayer composition (head group charge, tail length).
• An antigen (BSA)-sensitive interface was successfully designed by immobilizing anti-BSA antibodies.
• The integrated current, not channel event frequency, serves as a reliable analytical signal for BSA detection.
• Highly sensitive and selective detection of BSA was achieved at a concentration of 10(-9) g/mL.

Conclusions:

• Lipid bilayer composition effectively modulates gramicidin A channel behavior.
• The developed biosensing system demonstrates significant potential for sensitive and selective BSA detection.
• This approach offers a novel strategy for designing protein-sensitive interfaces for biomolecule quantification.