A label-free microfluidic assay to quantitatively study antibiotic diffusion through lipid membranes

Area of Science:

• Biophysics
• Membrane Transport
• Drug Discovery

Background:

• Antibiotic resistance is a growing global health threat.
• Understanding how antibiotics cross bacterial cell membranes is crucial for developing new treatments.
• Existing methods for measuring antibiotic permeability can be complex and indirect.

Purpose of the Study:

• To present a novel, label-free microfluidic assay for quantifying antibiotic permeability across lipid membranes.
• To determine the permeability coefficient of norfloxacin, a broad-spectrum fluoroquinolone antibiotic.
• To establish a more direct method for assessing drug transport across biological barriers.

Main Methods:

• Utilized a microfluidic device for precise control over experimental conditions.
• Employed giant lipid vesicles as model cell membranes.
• Quantified norfloxacin permeability using its intrinsic UV autofluorescence, avoiding external labels.
• Directly measured the permeability coefficient without needing partition coefficient data.

Main Results:

• Successfully quantified the permeability coefficient of norfloxacin across lipid membranes.
• Demonstrated a novel, label-free approach for antibiotic transport studies.
• Validated the use of giant lipid vesicles in a microfluidic system for membrane permeability analysis.

Conclusions:

• The developed microfluidic assay provides a sensitive and direct method for measuring antibiotic permeability.
• This technique can be applied to a broad range of antibiotics and lipid compositions.
• The findings contribute to a better understanding of antibiotic-cell membrane interactions and aid in the development of new antimicrobial strategies.