Generation and precise control of dynamic biochemical gradients for cellular assays

TL;DR

This paper introduces a microfluidic device capable of generating and controlling dynamic biochemical gradients for cellular assays, enabling precise spatial and temporal regulation of signaling molecules.

Contribution

The study presents a novel microfluidic design that stabilizes and dynamically controls biochemical gradients through passive diffusion without cross-flow, validated with yeast cell experiments.

Findings

Stable, dynamic gradients achieved in diffusion chambers

Yeast cells show concentration-dependent reporter expression

Device is versatile for various biomedical applications

Abstract

Spatial gradients of diffusible signalling molecules play crucial roles in controlling diverse cellular behaviour such as cell differentiation, tissue patterning and chemotaxis. In this paper, we report the design and testing of a microfluidic device for diffusion-based gradient generation for cellular assays. A unique channel design of the device eliminates cross-flow between the source and sink channels, thereby stabilising gradients by passive diffusion. The platform also enables quick and flexible control of chemical concentration that makes highly dynamic gradients in diffusion chambers. A model with the first approximation of diffusion and surface adsorption of molecules recapitulates the experimentally observed gradients. Budding yeast cells cultured in a gradient of a chemical inducer expressed a reporter fluorescence protein in a concentration-dependent manner. This microfluidic platform serves as a versatile prototype applicable to a broad range of biomedical investigations.