The Liu Lab at HHMI’s Janelia Research Campus has developed cycleHCR, an innovative imaging technique that tracks hundreds of RNA and protein molecules in single cells within thick tissue samples. This method uses novel DNA barcodes that tag specific molecules, allowing for multiple rounds of imaging on the same sample. Building upon Hybridization Chain Reaction (HCR) technology, the technique overcomes previous limitations by enabling detection of potentially thousands of molecular targets. Already successfully used to identify 254 genes in mouse embryos and discover previously uncharacterized cell types, cycleHCR promises applications across biological research and potentially diagnostic imaging. The Liu Lab has shared their barcode sequences and is developing a streamlined version of their system for broader scientific adoption.