Slow and remanent electric polarization of adsorbed BSA layer evidenced by neutron reflection

TL;DR

This study uses neutron reflectivity to demonstrate that BSA protein layers exhibit slow, remanent electric polarization at interfaces, influenced by initial electric potential, with implications for understanding protein dipolar behavior.

Contribution

It reveals the slow and remanent polarization of adsorbed BSA layers and proposes an analogy with spin glasses based on protein dipolar structure.

Findings

A second BSA layer forms depending on initial potential sign.

Reversal of potential does not affect the existing polarization.

The behavior suggests a spin-glass-like dipolar structure in BSA layers.

Abstract

Using neutron reflectivity together with an appropriate electrochemical cell, we have studied the effects of transverse electric field on the Bovine Serum Albumin (BSA) monolayer initially adsorbed at the interface of the aqueous solution and a conductive doped-silicon wafer. Depending on the sign of the initial potential, a second layer is adsorbed on top of the first whereas a subsequent reversal of potential has no effect. We show that this behavior reveals the slow and remanent electric polarization of the first BSA layer and suggest an analogy with spin glasses based on the dipolar structure of this protein.