# Protein Barcoding **Entity class:** Molecular labeling method **Collection:** [[collections/Neurotech|Neurotech]] **Canonical source articles:** [[articles/The Organic-Synthetic Brain Atlas|The Organic-Synthetic Brain Atlas]] · [[articles/Technologies for Consciousness Mapping and Transfer|Technologies for Consciousness Mapping and Transfer]] ## Definition **Protein barcoding** assigns cells combinatorial patterns of detectable protein tags so each labeled cell carries a machine-readable molecular identity. In [[wiki/PRISM (E11 Bio)|PRISM]], the barcode helps a reconstruction model recognize the same neuron across an expanded and repeatedly stained tissue volume. ## Forward Capability Barcode diversity grows combinatorially with the number of independently distinguishable protein bits. The governing variables are tag count, expression reliability, optical separability, tissue retention, and collision rate among cells in the imaged volume. PRISM's 18-bit design has a theoretical nonzero code space of 262,143 patterns. That code-space calculation is not the same as an experimentally observed count of uniquely labeled neurons, and neither establishes whole-brain coverage. ## Relationships - **Component of:** [[wiki/PRISM (E11 Bio)|PRISM]]. - **Developer:** [[wiki/E11 Bio|E11 Bio]]. - **Published evidence:** [[wiki/Combinatorial protein barcodes enable self-correcting neuron tracing with nanoscale molecular context|the PRISM preprint]] demonstrates a mouse CA2/CA3 pilot rather than a whole-brain connectome. - **Combined with:** [[wiki/Expansion Microscopy|expansion microscopy]] and [[wiki/Iterative Molecular Staining|iterative molecular staining]]. - **Collection route:** [[collections/Neurotech|Neurotech]]. ## Sources - [E11 Bio — PRISM](https://www.e11.bio/blog/prism) - [E11 Bio — roadmap](https://www.e11.bio/blog/roadmap)