Pixels are required to create an image on a display, such as the one you are reading this blogpost on. This is achieved by combining thousands of individual dots. Pixels keep getting smaller to provide us with ever-increasing screen resolutions, but scientists from the University of California have taken small pixels to a whole new level. They used bacteria as a source for pixels that, when aligned, are supposed to form a digital display. According to the developers, these displays will predominantly be used as sensors.
For their experiments, the scientists used E. coli bacteria, which are commonly found in our gut. By genetically engineering the microbes, they were able to produce fluorescent light. Additionally, they were made to light up synchronously, by putting them together on a single chip; the smallest chips contained about 500 bacterial colonies that were able to light up on demand.
Bacterial circuits such as those made at the University of California differ greatly from conventional chips. The microbial colonies are connected to each other by microfluidic chambers. Bacteria emit gas when the process of fluorescence is triggered, and by letting it flow through the chip, they are able to light up in a synchronously. The scientists already succeeded in making large chips that contain about 50-60 million bacterial cells, which all light up at the same time. All these bacteria are crammed on a microscopic slide with the size of a paper clip.
The bacteria are engineered in such a way that providing them with the right stimulant causes them to blink in concert with each other. And because of their known sensitivity to compounds such as arsenic, we may be able to use these arrays of bacteria as sensors: when coming into contact with the compound they are made to detect, we will be able to observe it by the light that will be emitted. According, to the scientists, using genetically engineered bacteria is cheaper than creating conventional sensors.
While we have put bacteria to good use before, this is probably the first time they are used as pixels. Currently, we use microbes to produce useful things, such as insulin for diabetics. We can also use them as markers for cancer. As for the pixels, in about five years time, we should be able to utilize the first bacterial fluorescent pixels as sensors. For now, we will have to settle for a video that was made of the experiment.