UV-DIB: label-free permeability determination using droplet interface bilayers

Area of Science:

• Biophysics
• Analytical Chemistry
• Materials Science

Background:

• Simple diffusion across phospholipid bilayers is vital for pharmaceutical and agricultural industries.
• Current methods using fluorescence have limitations in the range of chemical matter that can be studied.
• Existing droplet interface bilayer (DIB) technologies require improvement in reusability and detection limits.

Purpose of the Study:

• To develop and validate a novel UV-DIB platform for label-free measurement of small molecule translocation rates.
• To enable precise quantification of passive diffusion kinetics and assess structure-permeability relationships.
• To improve upon existing DIB technology with enhanced reusability, sampling rate, and detection sensitivity.

Main Methods:

• Coupling droplet interface bilayer (DIB) technology with fiber optics for ultraviolet (UV) spectroscopy analysis.
• Utilizing custom-designed PMMA wells for sample analysis.
• Validating the system by investigating multiple permeants with varying physicochemical properties across different lipid interfaces.

Main Results:

• The UV-DIB platform provides label-free, rapid, and reproducible quantification of passive diffusion.
• The system demonstrated sensitivity to lipid composition, showing reduced permeability with DPhPC compared to DOPC interfaces.
• The device successfully rank-ordered xanthine compounds based on minor structural differences, highlighting its precision in assessing permeant structure effects.

Conclusions:

• The UV-DIB is a powerful, reusable tool for label-free assessment of small molecule permeability through lipid bilayers.
• This technology overcomes limitations of fluorescence-based methods, expanding the range of assessable compounds.
• The platform's precision in evaluating structure-permeability relationships offers significant advantages for pharmaceutical and agrochemical research and development.