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Gold tattoos on cells to monitor them

Written by Paolo Rossi Castelli | 19 Oct 2023

Researchers at Johns Hopkins University have used a cutting-edge technique to attach nanoscale dots and wires to the cell membrane; in the future, these could connect to devices able to prevent and treat disease.

Researchers at Johns Hopkins University, in the United States, have used state-of-the-art technology to apply microscopic “tattoos” to individual living cells without damaging them.
Why did they do it?
In order to be able, in the future, to attach electronic sensors and devices capable of making highly precise early diagnoses and of monitoring certain types of diseases, and perhaps even of administeringtargeted” doses of medications. For now, the tattoos consist of individual dots, but the success of this study paves the way for more complex applications, and it shows that the biological functions of cells can be measured from inside the body, and not only using external devices like ultrasound or MRI machines, as is the case today.
“If we had technologies to track the health of isolated cells,” explains bioengineer David Gracias, who coordinated the study, “we could maybe diagnose and treat diseases much earlier and not wait until the entire organ is damaged.”

"Imprinting" nanoscale wires

Various types of devices (microchips and sensors), made to be placed inside of our bodies for the purpose of continuously monitoring either our vital functions in general or specific individual parameters, actually already exist, but all of these work at the level of the tissue or organs. The researchers at Johns Hopkins, however, have been able to scale down to a much more “refined” level, that of the individual cell. “It's the first step,” Gracias added, “toward attaching sensors and electronics on live cells.”
How did they do it?
Using a technique called nanoimprint lithography, which uses materials on the tiniest of scales, on the order of a millionth of a millimetre. Firstly, they “stamped” gold tattoos (patterns composed of dots and wires) onto a nanoscale plate” made of silicon. The resulting arrays were then treated with a special molecular glue before being transferred onto the cells using an hydrogel film, which later dissolved, leaving the tattoos adhered to the cells without damaging them. The entire procedure was described in the scientific journal Nano Letters.

The device works for 16 hours

Each cell, the researchers write, could host numerous nanochips, which, working in concert, would be able to provide a wealth of information about the health of the cell itself and, as a consequence, that of the organ where it is located and its surrounding environment. During the tests carried out, the gold nano-tattoos continued to record information for 16 hours straight, without causing any harm to the cells.