‘Simple yet powerful’: Seeing cell secretion like never before

Aug. 8, 2022
Singamaneni’s lab, collaborators develop new assay that detects protein secretion from cells.

Washington University in St. Louis researchers have developed a novel method for visualizing the proteins secreted by cells with stunning resolution, making it the James Webb version for visualizing single cell protein secretion.

The researchers, led by Srikanth Singamaneni, the Lilyan & E. Lisle Hughes Professor of Mechanical Engineering & Materials Science at the McKelvey School of Engineering, and Anushree Seth, a former postdoctoral scholar in Singamaneni’s lab, developed the FluoroDOT assay, which they introduced in a paper Aug. 5 in the journal Cell Reports Methods. The highly sensitive assay is able to see and measure proteins secreted by a single cell in about 30 minutes.

In collaboration with researchers at Washington University School of Medicine and other universities, they found that the FluoroDOT assay is versatile, low cost and adaptable to any laboratory setting and has the potential to provide a more comprehensive look at these proteins than the widely used existing assays. Biomedical researchers look to these secreted proteins for information on cell-to-cell communication, cell signaling, activation and inflammation, among other actions, but existing methods are limited in sensitivity and can take up to 24 hours to process.

What makes the FluoroDOT assay different from existing assays is that it uses a plasmonic-fluor, a plasmon-enhanced nanolabel developed in Singamaneni’s lab that is 16,000 times brighter than conventional fluorescence labels and has a signal-to-noise ratio nearly 30 times higher.

This ultrabright emission of plasmonic-fluor allows the user to see extremely small quantities of secreted protein, which they are unable to do in existing assays, and measure the high-resolution signals digitally using the number of particles, or dot pattern, per cluster, or spot, using a custom-built algorithm. In addition, it doesn’t require special equipment. Singamaneni and his collaborators first published their work with the plasmonic-fluor in Nature Biomedical Engineering in 2020.

Washington University in St. Louis release