I came across this fascinating article earlier this week and it just grabbed my attention because it’s not often you see the term ‘bacteria and digital technology in medicine’.
Bugs are not normally welcome in digital technology, but that’s about to change. Researchers have apparently developed a way to control bacterial genes at the flick of a switch using electricity. Very cool stuff, with massive implications for technology in medicine. I won’t pretend to understand it all, however, as you read on it begins to make more sense.
Synthetic biologists are eager to find ways to connect engineered organisms to electronics, so we can make living components for devices. So it seems the future of technology in medicine is to have friendly organisms implanted into our bodies to detect and treat potentially harmful things that may be lurking within.
Technology in Medicine: Connecting Bacteria to Electrodes
The ability of custom-made microbes to sense the environment and make biological molecules would be particularly valuable for devices. I wonder what type of devices this technology could be used in? It’s very much in the infancy stage at present, but that being said, it sounds remarkable. This is the work being undertaken by William Bentley at the University of Maryland.
“Let’s say you want to discover what’s going on in the gastrointestinal tract or the oral cavity. If you can connect to electronics you have a way of interpreting what’s going on and you may be able to manipulate it,” he says. “A way of controlling bacteria via electricity.”
For example, a device could use an organism to sense chemicals produced by harmful bacteria in the body and secrete an antibiotic when it detects them.
To get specific genes in bacteria to respond to electrical stimulation, Bentley’s team took advantage of what are called redox molecules. These biological molecules are found in all cells and can pick up and pass on electrons. They are said to have a reduced state when they gain electrons, and an oxidised state when they lose electrons.
The team have also made use of naturally occurring genetic components in E. coli that respond to oxidative stress, which occurs when too many molecules in the cell are oxidised, making them dangerously reactive.
To apply electrical input, the researchers submerged an electrode in a liquid containing the bacteria. When the electrode supplies a positive charge, certain redox molecules get oxidised and trigger the genetic mechanisms that respond to oxidative stress. This all sounds amazing, doesn’t it? I would love to see this tech in action.
The bacteria can be engineered so that these mechanisms switch on any genes researchers want to target. When the electrode is negatively charged, the molecules get reduced and the genes switch off again.
Using this principle, Bentley’s team showed they can use electrical inputs to make E. coli swim or fluoresce on demand.
They also made the bacteria release a signalling molecule that caused other bacteria to fluoresce, showing that they can engineer one set of bacteria to respond to the electrical charge by altering the behaviour of another set.
The procedure involves relatively little genetic “rewiring” of the bacteria, says Bentley. “We like to think about how you can minimally alter cells, but alter what they do in a controlled way.”
Bioengineering Bacteria with Digital Technology
One application could be in biosensors using engineered bacteria that detect certain chemicals. For example, bacteria could be programmed to identify a particular infection and respond by fluorescing. I wonder if it could be used to detect cancer, and the genes that sometimes cause it.
Richard Kitney, a synthetic biologist at Imperial College London, thinks its uses could be developed quite quickly. “To get it working in the lab, you might be talking about a year or two,” he says.
Further down the line, Bentley imagines programmed bacteria being used in ingestible pills that collect chemical data and produce drugs inside the body.
Imagine you are feeling unwell, you take one of these ingestible pills, it detects the irregularities in your cells, treats them and you’re cured. Particularly as we are reaching crisis point with our use of antibiotics, an alternative is urgently required. For example, one troubling story published in New Scientist this week reports that a woman in Nevada died from an infection that resisted 26 different types of antibiotics. Such technology in medicine such as this may offer a potential solution, and perhaps negate the harmful effects that overuse of antibiotics is creating.