The Need

Understanding how cells respond to soluble signals under diffusion-limited conditions remains a significant gap in current in vitro models. Most microfluidic systems rely on convective flow, which does not accurately reflect transport in interstitial tissue or solid tumors, where diffusion dominates. Even minimal pressure differences can introduce unintended flow, confounding results. There is a clear need for a simple, robust, and accessible platform that enables reproducible, diffusion-only studies of cell signaling with high spatial and temporal resolution.

The Technology

OSU engineers have developed a novel microfluidic assay that enables the generation of stable lateral concentration gradients exclusively through diffusion. By temporarily occluding the outlet of a standard microfluidic channel, convective flow is eliminated, ensuring that soluble factors move only by diffusion from a source reservoir. Gradients are established with a single pipetting step and can be directly correlated with live-cell, spatially resolved signaling responses using optical microscopy and molecular biosensors.

Benefits/Advantages

• True diffusion-only conditions
• High compatibility with live-cell imaging
• Easy to use
• Reusable and adaptable design