Starting a fluorescent biosensor revolution

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"Now, a collaborative research team ... has developed a synthetic biology platform to streamline the discovery, molecular evolution, and cost-effective manufacturing of small and highly efficient nanosensors that can detect specific proteins, peptides, and small molecules by increasing their fluorescence up to 100-fold in less than a second. As a key component, the platform uses new fluorogenic amino acids (FgAAs) that can be encoded into target-binding small protein sequences (binders) with the help of an innovative methodology that enables the in vitro expansion of the genetic code. Through a process of high-throughput sensor screening, validation, and directed evolution, the platform enables the rapid and cost-effective transformation of protein binders into high-contrast nanosensors for a wide range of applications in fundamental research, environmental monitoring, medical diagnostics and augmented therapeutics. ..."

From the absract:

"Binding-activated optical sensors are powerful tools for imaging, diagnostics, and biomolecular sensing. However, biosensor discovery is slow and requires tedious steps in rational design, screening, and characterization. Here we report on a platform that streamlines biosensor discovery and unlocks directed nanosensor evolution through genetically encodable fluorogenic amino acids (FgAAs). Building on the classical knowledge-based semisynthetic approach, we engineer ~15 kDa nanosensors that recognize specific proteins, peptides, and small molecules with up to 100-fold fluorescence increases and subsecond kinetics, allowing real-time and wash-free target sensing and live-cell bioimaging. An optimized genetic code expansion chemistry with FgAAs further enables rapid (~3 h) ribosomal nanosensor discovery via the cell-free translation of hundreds of candidates in parallel and directed nanosensor evolution with improved variant-specific sensitivities (up to ~250-fold) for SARS-CoV-2 antigens. Altogether, this platform could accelerate the discovery of fluorogenic nanosensors and pave the way to modify proteins with other non-standard functionalities for diverse applications."

Starting a fluorescent biosensor revolution "Molecular biosensors that only light up upon binding their targets open vast possibilities for medical diagnostics, fundamental research, environmental monitoring, and more"

Rapid discovery and evolution of nanosensors containing fluorogenic amino acids (open access)

Fig. 1: A platform to discover, evolve, and produce FgAA-containing NS.

Binding-activated biosensors exposed to an “excitation light” of a specific wavelength only emit fluorescent light of a different fluorescent wavelength when their fluorogenic scaffolds are sandwiched between the biosensor protein and target protein.