https://thenextweb.com/artificial-intelligence/2018/07/05/scientists-created-an-artificial-neural-network-out-of-dna/

A team of scientists at the California Institute of Technology have successfully created a DNA-based neural network capable of performing pattern recognition.

TLDR: The researchers demonstrated that bio-engineered strands of DNA could be used to process data by exploiting chemical reactions. Basically, they made molecular smart soup, poured it into a test tube, and taught it how to recognize nine distinct patterns.