Fluorescent probes have reshaped how biologists study living systems, making it possible to watch viruses invade cells, follow the cell’s internal waste‑disposal machinery, and track the signaling events that fuel tumor growth. Yet even with decades of innovation, a fundamental limitation has persisted: most fluorescent nanobody probes glow whether or not they are bound to their targets. That constant background haze can blur the very molecular details researchers are trying to resolve.

A new imaging platform developed by scientists at Albert Einstein College of Medicine and the Salk Institute for Biological Studies aims to eliminate that problem entirely. The technology, described in Nature Methods in a paper titled “Synthetic multicolor antigen-stabilizable nanobody platform for intersectional labelling and functional imaging,” uses engineered fluorescent nanobodies that become brightly fluorescent only when they bind their intended protein targets. These “on‑demand” probes, known as VIS‑Fbs (visible-spectrum target-stabilizable fluorescent nanobodies), illuminate proteins inside living cells and animals with far greater clarity than conventional tools.

“The key advantage of our approach is that the signal appears only where the target protein is present,” said Vladislav Verkhusha, PhD, co‑corresponding author and professor of genetics at Einstein. “That eliminates the background glow that has long limited the precision of intracellular imaging.” His collaborator, Axel Nimmerjahn, PhD, professor and the Françoise Gilot‑Salk Chair at Salk, added, “This work establishes a versatile platform for imaging proteins with high specificity and minimal background. It opens new opportunities to study how molecular and cellular processes unfold in real time across diverse biological systems.”

Nanobodies have become increasingly valuable for live‑cell imaging because they can be engineered to bind specific proteins with high affinity. But their ongoing fluorescence has remained a stubborn obstacle. The VIS‑Fb design solves this by making the probes unstable when unbound; they rapidly degrade unless they encounter their target. Binding stabilizes the nanobody and triggers bright fluorescence, reducing background noise by as much as 100‑fold. The team also created VIS‑Fbs that span nearly the entire visible spectrum, from blue to far red, enabling simultaneous tracking of multiple proteins or cellular processes within the same cell.

The researchers developed a modular engineering platform, instead of a single probe, capable of generating VIS‑Fbs for a wide range of targets and experimental needs. They integrated more than 20 fluorescent proteins and biosensors into multiple nanobody scaffolds, creating a flexible system that supports multicolor imaging, light‑switchable variants for precise temporal control, and functional readouts of ions and metabolites. This allows the probes not only to show where proteins are but also to show what those proteins are doing in real time. According to first author Natalia Barykina, PhD, “The VIS‑Fb approach allows us to identify and track specific cell populations in living organisms based on the proteins they express, rather than just their location.”

In mice, VIS‑Fbs allowed for high‑contrast imaging of neuronal and astrocyte activity during behavior. In zebrafish embryos, the probes captured rapid developmental changes and responses to drugs that modulate signaling pathways. “Our results show that this imaging platform offers a much clearer and more precise view of how proteins behave inside living systems,” Verkhusha said. “It opens the door to studying complex biological processes, such as cell signaling, development, and disease progression, in new ways.”

The post Antigen‑Stabilized Nanobody Probes Enable On‑Demand, Multicolor Protein Imaging appeared first on GEN – Genetic Engineering and Biotechnology News.

Vani Hari has 2.3 million followers on Instagram, and about as many ideas for healthy food swaps. An entrepreneur and influential food activist in the Make America Healthy Again movement, Hari gives regular shout-outs to substitutes for snacks that contain corn syrup, seed oils, and other ingredients on health-conscious Americans’ blacklist.

For Valentine’s Day, YumEarth choco yums instead of artificially dyed M&Ms. (“Let me say these treats are BETTER, but they are still candy,” Hari writes.) For Super Bowl parties, Jackson’s avocado oil potato chips rather than Lay’s. Looking for a less processed alternative to Chick-fil-A’s frosted lemonade? Why not make your own with lemon-flavored protein powder from Hari’s own brand, Truvani. At least one attempt at a healthy food swap struck out with Hari: PepsiCo’s recently debuted dye-free line of Cheetos and Doritos. “This is dumb,” she wrote on Instagram. “Creating a whole NEW product, instead of FIXING their old product.” 

Though the vast majority — 84% — of Americans said eating healthfully was at least moderately important to them in a recent Deloitte survey, most admit their own habits fall short of their aspirations. The $156 billion packaged snack industry has spotted a business opportunity in catering to people seeking a more enlightened way of noshing. 

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