Autonomous Molecular Cascades for Evaluation of Cell Surfaces

Molecular automata are mixtures of molecules that undergo precisely defined structural changes in response to sequential interactions with inputs(1–4). Previously studied nucleic acid-based-automata include game-playing molecular devices (MAYA automata(3,5)) and finite-state automata for analysis of nucleic acids(6) with the latter inspiring circuits for the analysis of RNA species inside cells(7,8). Here, we describe automata based on strand-displacement(9,10) cascades directed by antibodies that can analyze cells by using their surface markers as inputs. The final output of a molecular automaton that successfully completes its analysis is the presence of a unique molecular tag on the cell surface of a specific subpopulation of lymphocytes within human blood cells.