Click-FAST: FAST and click chemistry combined together for à-la-carte fluorescent reporting!  OHSU’s David M. Anderson et al. have just disclosed alkyn-equipped fluorogens, empowering FAST with click chemistry, in bioRxiv 2023.

While FAST is a rapidly developing genetically-encoded fluorescent imaging technology that exhibits tremendous potential […] we sought to develop a modular platform, Click-FAST, to democratize fluorogen engineering for personalized use cases.

D. Anderson & al.


Click-FAST in bioRxiv © 2023 The Authors

To that end, leveraging FAST with the endless range of possibilities opened by click chemistry was a strategy of choice.  Click-equipped fluorogens would indeed allow adding a broad range of desired functionalities to the parental fluorogen.

The authors disclose two novel fluorogens, tfPoppy-alkyne and plBlaze-alkyne, which both incorporate a terminal alkyne moiety.  They further clicked those onto various reagents, i.e., azido benzoic acid and azido lactose.  The adduct fluorogens allowed for selective bacterial labeling in mixed populations.  Furthermore, adduct fluorogens enjoyed fluorescent signal enhancement!  Beyond, the authors even conjugated an 80 Å PEG molecule to PLBlaze-alkyne, hence illustrating the broad size range of functional fluorogen chimeras.  The PEGylated fluorogen functions as an exquisitely selective membrane permeability marker.  It is even capable of outperforming propidium iodide as a fluorescent marker of cell viability.

While they belong to OHSU’s School of Dentistry, the initial driver of authors was about deciphering polymicrobial interactions and microbiome-host interactions within anaerobic environments.  Obviously, their work paves the way to further loads of applications in cell biology and microbiology.

The Twinkle Factory offers commercial fluorogens for FAST, pFAST, greenFAST & redFAST, frFAST, and their related split versions, e.g., splitFAST.  tfFox-NP, a brighter non-permeant fluorogen, and tfDarth, a quencher, have recently completed the product range.