Novel Biosensor Uses DNA Barcodes to Uncover Disease Signals in Cells

Source: RNA-Seq Blog, by RNA-Seq Blog (October 8, 2026). AI-generated summary by biochip.com, published October 10, 2026. Not independently reviewed.

Researchers at the Gladstone Institutes have developed a programmable biosensor called Detectron that turns the detection of a chosen RNA sequence into a durable DNA barcode. The system combines bacterial retron machinery, which naturally makes small DNA strands, with an RNA-sensing molecular switch. In experiments with bacteria and bacteriophages, the team used those barcodes to identify which virus had infected cells in a mixed sample. The work, published in Nature Biotechnology, points toward a way to track many RNA signals at once without relying on a limited palette of fluorescent labels.

An RNA Sensor That Leaves a DNA Record

RNA is a working copy of genetic information that cells use to make proteins and regulate activity. Because RNA levels can change when genes switch on, cells encounter viruses, or diseases alter cell behavior, measuring specific RNA molecules can reveal what is happening inside a cell.

Detectron is designed as a molecular tripwire. When its programmed sensor recognizes a target RNA, it activates production of a small DNA sequence with a known identity. Researchers can then read that sequence by standard DNA sequencing, using it as a barcode that records which RNA trigger was present.

Borrowing Tools From Bacteria

The platform draws on retrons, bacterial systems that can produce short pieces of DNA inside cells. Retrons are part of bacterial antiviral defenses, but Seth Shipman's laboratory has repurposed their DNA-making ability for synthetic biology tools.

To make Detectron RNA-responsive, the team coupled the retron to a toehold switch. This switch is a hairpin-shaped RNA structure, much like a folded latch: it stays closed until a matching RNA sequence binds to it. Binding opens the structure and permits the DNA-producing machinery to operate.

Traditional toehold switches often signal RNA detection by producing fluorescent proteins. That approach is useful, but fluorescent colors are finite, limiting how many different RNA targets researchers can monitor in the same experiment. DNA barcodes offer far more possible labels because their sequences can be varied extensively.

Testing Phage Detection in Bacteria

Jihoon Han and colleagues tested Detectrons in Escherichia coli bacteria using bacteriophages, viruses that infect bacteria. The team programmed different bacterial populations with Detectrons designed to recognize RNA from different phages, then combined those populations and exposed them to individual phages.

When a phage successfully infected its matching bacterial population, the corresponding Detectron produced more of its assigned DNA barcode. By measuring the barcodes, the researchers could identify which phage had infected the cells. The experiments included three biological replicates and comparisons against controls without the functional RNA-sensing switch or with scrambled RNA sequences.

A Potential Tool for Phage Screening

Phage therapy uses bacteriophages to attack harmful bacteria and is being investigated as one approach to infections that no longer respond to conventional antibiotics. Selecting a useful phage can be laborious because candidates are commonly tested one at a time against a bacterial strain.

Detectron could support a more multiplexed approach, in which many phage-related RNA signals are assessed together through their unique DNA labels. The Gladstone team presents the bacterial experiment as a demonstration of how the platform might help narrow down phages that infect a particular bacterial target.

Why This Matters

Many important cellular signals are temporary. Detectron aims to convert a fleeting RNA event into a more stable DNA output that can be sequenced later. That capability could make it easier to study RNA-dependent processes across large collections of cells or targets.

The researchers also suggest that RNA-responsive switches could eventually add control layers to cell therapies. For example, a gene-editing system might theoretically remain inactive until it encounters RNA found in the intended cell type. That use remains a concept rather than a demonstrated therapeutic application.

What Comes Next

Detectron has so far been demonstrated in bacterial settings, and the team is investigating how to adapt it for human cells, which have a substantially different molecular environment. The researchers are also working to detect RNA fragments hundreds of times longer than those tested in this study. Shipman's group has made its Detectron schematics and programming code available for other laboratories to build on the platform.

Topics: Biosensors · Infectious diseases

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