Lulu Qian

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Neural network computation with DNA next

Before neuron-based brains evolved, complex biomolecular circuits provided individual cells with the ‘intelligent’ behavior required for survival. However, the study of how molecules can ‘think’ has not yet produced artificial chemical systems that mimic even a single neuron. Building on the richness of DNA computing and strand displacement circuitry, we show how molecular systems can exhibit autonomous brain-like behaviors. We systematically transform arbitrary linear threshold circuits (an artificial neural network model) into DNA strand displacement cascades that function as small neural networks. Our approach even allows us to implement a Hopfield associative memory with four fully connected artificial neurons that, after training in silico, remembers four single-stranded DNA patterns and recalls the most similar one when presented with an incomplete pattern. Our results suggest that DNA strand displacement cascades could be used to endow autonomous chemical systems with the capability of recognizing patterns of molecular events, making decisions and responding to the environment.

[1] Neural network computation with DNA strand displacement cascades. Lulu Qian, Erik Winfree, and Jehoshua Bruck. Nature, 475:368-372, 2011. (pdf) (supp info)
[2] News and Views: "DNA and the brain" by Anne Condon, 475:304-305. (pdf)