Concentration Gradient Generation and Control

Synonyms

Diffusion-based mixing

Definition

The concentration gradient of a solute is the change of concentration per unit distance in a solution. A concentration gradient is generated by diffusion between two regions where the concentration of a substance differs; diffusion proceeds until the concentrations in the two regions become equal.

Overview

Concentration gradients of diffusible molecules play an important role in many biological and chemical processes, such as chemotaxis, nerve growth cone guidance, surface patterning, and microfabrication. Traditional approaches (e. g., the Boyden chamber [1], micropipettes [2], generation under agarose [3], and derivatives of these approaches [4,5]) are mainly used to release factors and investigate cell behavior subject to a concentration gradient. Although instrumental in furthering many biological studies, none of these methods are effective for generating stable gradients of complex shape, owing to the unbalanced flux of soluble factor...