Artificial cells pass the Turing test

Real and artificial cells communicate chemically.

To pass the classic Turing test, a computer must convince the tester that it’s human. In a new ACS Central Science study, Sheref S. Mansy and colleagues got artificial cells to communicate chemically with living bacterial cells. The artificial cells demonstrated that they heard the natural bacterial cells by glowing and responded by releasing chemical signals back to the bacteria.

We spoke to Mansy about the work.

ResearchGate: What is the Turing test?

Sheref S. Mansy: The Turing test was formulated over sixty years ago to evaluate whether a machine could behave intelligently. One nice aspect of this test was that it avoided the contentious issue of defining intelligence. Instead, if a machine can trick a person through textual communication into believing that the machine is another person, and thus not a machine, then the machine must display some level of intelligence to pull off this deception.

RG: What motivated your study?

Mansy: We have been interested in the divide between living and nonliving chemical systems for quite some time now, but it was never really clear where this divide fell. Then a couple of papers pointed out that a cellular version of the Turing test could conceivably be built and thus provide a much-needed benchmark for the field. All cells engage in some form of chemical communication. If we could build an artificial cell that can trick a natural cell into "thinking" that it is talking to another natural cell, then we would have made a big step forward in constructing a more life-like chemical system. We felt that we were well positioned to put together artificial cells that could engage in two-way chemical communication with bacteria, i.e. artificial cells that could be used in a cellular version of a Turing test. We also realized that the cellular Turing test could be used to quantify how life-like the artificial cells are.

RG: What did you find?

Mansy: First, it is absolutely possible to make artificial cells that can chemically communicate with bacteria. Artificial cells can sense the molecules that are naturally secreted from bacteria and in response synthesize and release chemical signals back to the bacteria. Such artificial cells do a reasonably good job of mimicking natural cellular life and can be engineered to mediate communication paths between organisms that do not naturally speak with each other.

RG: How did you go about discovering this?

Mansy: Mostly through the hard work of two excellent PhD students (Roberta Lentini and Noël Yeh Martín). They had to become highly proficient in several techniques to get this project to work. They even quantified how life-like the artificial cells were through RNA-seq analysis of the bacteria that chemically communicated with the artificial cells.

RG: What is the significance of your findings?

Mansy: In some ways, our artificial cells told us that a big part of what makes extant life work is the ability to synthesize proteins. The artificial cells were quite life-like for a short period of time, but this chemical system was completely reliant on translation machinery that was isolated from bacteria. The artificial cells could not produce their own translation machinery. To make more advanced and life-like artificial cells, the artificial cells would need to synthesize their own translation machinery, which is a daunting task. Either we figure out how to do this, or we'll have to find a way to build artificial cells that are not reliant on the activity of proteins.

We also found that artificial cells can interfere with the signaling of pathogenic bacteria. If developed further, such artificial cells could be used to disrupt biofilms and thus help to clear infections.

RG: What are the next steps in your research?

Mansy: We would like to build a consortium of different kinds of artificial cells and bacteria.

RG: How will the cellular Turing test help you going forward?

Mansy: A cellular Turing test is one of several ways forward. What we particularly like about this approach is that a cellular Turing test provides for a way to quantify success. Metric based approaches to the study of artificial cells (and protocells) will likely facilitate progress in elucidating the foundational principles of biology.

Image credit Wiki Media.