Profiling the proteins that cells are making is a staple of studies in biology, neuroscience, and related fields because the proteins a cell is expressing at a given moment can reflect the functions the cell is trying to perform or its response to its circumstances, such as disease or treatment. As much as microscopy and labeling technologies have advanced, scientists have still lacked a reliable and practical way of tracking protein expression at the level of millions of densely packed individual cells in whole, 3D intact tissues. Often confined to thin tissue sections under slides, scientists therefore haven’t had tools to thoroughly appreciate cellular protein expression in the whole, connected systems in which it occurs.

A new technology unveiled in Nature Biotechnology by the lab of Professor Kwanghun Chung in 2025 enables scientists to label proteins across millions of individual cells in fully intact 3D tissues with unprecedented speed, uniformity, and versatility. Using the technology, called “CuRVE,” the team was able to richly label large tissue samples in a single day. 

The fundamental reason why large, 3D tissue samples are hard to label uniformly is that antibodies seep into tissue very slowly, but are quick to bind to their target proteins. The practical effect of this speed mismatch is that simply soaking a brain in a bath of antibodies will mean that proteins are intensely well labeled on the outer edge of the tissue, but virtually none of the antibodies will find cells and proteins deeper inside. The new approach, and a specific implementation called “eFLASH,” provides a fundamentally new approach to uniformly processing large and dense tissues whole. 

eFLASH overcomes the barriers by accelerating dispersion of labeling antibodies while also continuously modifying their binding speed. Antibodies end up more evenly distributed throughout the tissue. In all, the team reported using more than 60 different antibodies to label proteins in cells across large tissue samples such as a whole rat brain. 

See examples of the technology at work in the videos below.

Staining of all neurons (cyan) across an entire intact rat brain

A mouse brain hemisphere stained with various cell type markers: neurons overall (cyan), and cells specifically involved with neurotransmitters dopamine (yellow) and acetylcholine (magenta).