Polydopamine Coating To Stabilize a Free-Standing Lipid Bilayer for Channel Sensing

Abstract

An appropriate method to study the function of membrane channels is to insert them into free-standing lipid bilayers and to record the ion conductance across the membrane. The insulating property of a free-standing lipid bilayer versus the single-channel conductivity provides sufficient sensitivity to detect minor changes in the pathway of ions along the channel. A potential application is to use membrane channels as label-free sensors for molecules, with DNA sequencing as its most prominent application. However, the inherent instability of free-standing bilayers limits broader use as a biosensor. Here we report on a possible stabilization of free-standing lipid bilayers using polydopamine deposition from dopamine-containing solutions in the presence of an oxidant. This stabilization treatment can be initiated after protein reconstitution and is compatible with most reconstitution protocols.

Ultrathin Polydopamine Films with Phospholipid Nanodiscs Containing a Glycophorin A Domain

“…[ 16 ] PDA ( Figure A) is considered biocompatible, it is resistant to a number of reagents, highly adhesive to various materials and surfaces [ 17 ] and hence, it has been used for functionalization of many substrates. [ 18,19 ] There is a rich chemistry available, via which PDA surfaces could be functionalized, for example, with Schiff base reactions or Michael additions. Freestanding PDA films with a thickness of several hundreds of nanometers or even micrometers have been synthesized before.…”

Thickness dependence of polydopamine thin films on detection sensitivity of surface plasmon-enhanced fluorescence biosensors

“…22,23) PDA coating techniques have been extensively studied as they hold various important properties for a wide range of applications. [24][25][26] One of their notable advantages is that PDA films can be used for coating various materials including metals, oxides and polymers by simply applying the dopamine solution onto the surface and incubating the solution. 23) Furthermore, biomolecules including amine and thiol groups can be directly bonded onto PDA films through the Michael addition and=or Schiff base reaction.…”