Micrometer-sized supported lipid bilayer arrays for bacterial toxin binding studies through total internal reflection...

Area of Science:

• Biophysics
• Surface Chemistry
• Microfluidics

Background:

• Supported lipid bilayers (SLBs) are crucial models for cell membranes.
• Bacterial toxins interact with specific lipids, making them targets for study.
• Microscopy techniques allow visualization of molecular interactions.

Purpose of the Study:

• To develop a method for patterning micron-sized lipid domains for toxin binding assays.
• To investigate the influence of the lipid microenvironment on toxin-receptor interactions.
• To demonstrate the utility of patterned SLBs in microfluidic devices for selective binding.

Main Methods:

• Micron-sized lipid domains were patterned using a polymer lift-off technique on planar substrates and within microfluidic channels.
• Ganglioside-populated distearoylphosphatidylcholine:cholesterol SLBs were created.
• Total internal reflection fluorescence microscopy (TIR-FM) was used to assay toxin binding.

Main Results:

• Binding of cholera toxin B subunit and tetanus toxin C fragment was detected with high sensitivity (down to 100 pM and 10 nM, respectively).
• Toxin binding constants were influenced by the SLB microenvironment and substrate.
• Patterned SLBs in microfluidic channels enabled segregation and selective binding from a mixture.

Conclusions:

• The developed method allows for precise patterning of lipid microarrays for studying molecular interactions.
• This technique is adaptable for proteins and nucleic acids, with potential applications in biosensors and cell stimulation assays.
• Patterned SLBs in microfluidics offer a versatile platform for complex biological assays under controlled flow conditions.