Sharp, localized phase transitions in single neuronal cells

TL;DR

This study demonstrates that single human neuronal cells exhibit sharp, reversible phase transitions in their membrane properties, which are triggered by temperature and pH, indicating nonlinear behavior similar to physical phase transitions.

Contribution

The paper provides the first evidence of sharp, reversible phase transitions in single neuronal cells, linking biological nonlinear responses to physical phase transition phenomena.

Findings

Cells display optical features of phase transitions.

Transitions are reversible and not due to protein denaturation.

Membrane changes affect permeability, enzyme activity, and electrical properties.

Abstract

The origin of nonlinear responses in cells has been suggested to be crucial for various cell functions including the propagation of the nervous impulse. In physics nonlinear behavior often originates from phase transitions. Evidence for such transitions on the single cell level, however, has so far not been provided leaving the field unattended by the biological community. Here we demonstrate that single cells of a human neuronal cell line, display all optical features of a sharp, highly nonlinear phase transition within their membrane. The transition is reversible and does not origin from protein denaturation. Triggered by temperature and modified by pH here, a thermodynamic approach, strongly suggests, that similar nonlinear state changes can be induced by other variables such as calcium or mechanical stress. At least in lipid membranes such state changes are accompanied by significant changes in permeability, enzyme activity, elastic and electrical properties.