Method and device for assaying the interaction and dynamics of permeation of a molecule and a lipid bilayer

A method of assaying permeation of a test molecule across a lipid bilayer that employs a microfluidic device comprising:

• a substrate having at least one concave microcavity defining an aperture and having a metallic surface, and a liquid disposed within the microcavity;
• a lipid bilayer suspended across the aperture;
• and
• a microfluidic channel containing a liquid disposed on top of the substrate in fluid communication with the lipid bilayer,
• in which the liquid in the microcavity is separated from the liquid in the microfluidic channel by the suspended lipid bilayer,
• the method comprising the steps of:
• passing a liquid containing a test molecule across the microfluidic channel;
• monitoring the intensity of a Raman or fluorescent signal from the test molecule as it permeates across the lipid bilayer and into the liquid in the microcavity and arrives at a metal enhanced plasmonic field within the microcavity by plasmonically-enhanced Raman or fluorescent spectroscopy;
• and
• determining an arrival time of the test molecule in the liquid in the microcavity, wherein the arrival time is a period of time calculated from when the test molecule is administered at a proximal interface of the lipid bilayer until the test molecule reaches the metal enhanced plasmonic field within the microcavity.