Nanoscale Tattoos Adhered to Live Cells Could Enable Early Disease Diagnosis

In a groundbreaking advancement, a team of engineers has created nanoscale tattoos—microscopic dots and wires capable of adhering to live cells—marking a significant step towards the ability to monitor the health of individual cells. For the first time ever, this novel technology offers the ability to place optical components and electronics onto live cells using tattoo-like arrays. These arrays possess the remarkable ability to adhere to cells while flexibly conforming to their fluid and moist external structure.

Researchers at Johns Hopkins University (Baltimore, MD, USA) built these "tattoos" in the form of arrays constructed from gold, a material renowned for its capacity to prevent signal loss or distortion in electronic wiring. These arrays were affixed to fibroblasts, cells responsible for generating and maintaining bodily tissue. To accomplish this, the arrays were treated with molecular adhesives and then delicately transferred onto the cells using an alginate hydrogel film—an adaptable gel-like laminate that can be dissolved after the gold adheres to the cell. The molecular adhesive on the array binds to the cells' extracellular matrix—a film secreted by the cells. Previous research had demonstrated how hydrogels could be used to adhere nanotechnology to human skin and internal animal organs. However, the current research distinguishes itself by showcasing the technique's application in attaching nanowires and nanodots to individual cells. This addresses the long-standing challenge of making optical sensors and electronics compatible with biological material at the single-cell level.

Image: gold nanodot array on a fibroblast cell (Photo courtesy of Johns Hopkins University)

These "tattoos," akin to barcodes or QR codes, effectively bridge the gap between living cells or tissue and traditional sensors and electronic materials. The research team's achievement in arranging dots and wires into an array format is also vital. For this technology to be employed in tracking bioinformation, it is essential for researchers to arrange sensors and wiring in specific patterns, similar to how they are organized in electronic chips. The team's future goals include attaching more complex nanocircuits that can remain adhered for longer periods and experimenting with various cell types to expand the applications for this innovative technology.

"If you imagine where this is all going in the future, we would like to have sensors to remotely monitor and control the state of individual cells and the environment surrounding those cells in real time," said David Gracias, a professor of chemical and biomolecular engineering at Johns Hopkins University who led the development of the technology. "If we had technologies to track the health of isolated cells, we could maybe diagnose and treat diseases much earlier and not wait until the entire organ is damaged."

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