Beyond Traditional SPAAC: Achieving Orthogonality and Rapid Kinetics with Fluoroalkyl Azides

Le résumé fourni par la source

Strain-promoted azide–alkyne cycloaddition (SPAAC) is a cornerstone of bioorthogonal chemistry, offering metal-free and biocompatible ligation for applications ranging from bioconjugation to live-cell imaging. However, its relatively slow kinetics and limited selectivity hinder the simultaneous labelling of multiple targets. Here, we report on a systematic study of fluoroalkyl azides (RCF₂N₃) as novel SPAAC reagents that display enhanced reactivity with electron-rich cyclooctynes such as BCN, while showing significantly reduced reactivity with electron-deficient dipolarophiles such as DIBAC. Kinetic measurements revealed over 100-fold rate differences depending on the azide–alkyne pair, enabling orthogonal bioconjugation in both purified proteins and living cells. Experimental and computational data support the rate trends and mechanistic rationale based on electronic complementarity. Fluorescently labelled fluoroalkyl and alkyl azide probes demonstrate the selective labeling of BCN- and DIBAC-modified antibodies and lectin protein in vitro and the selective labelling of organelles in living cells. This dual-selectivity strategy enables orthogonal SPAAC labeling and paves the way for advanced applications in multiplexed imaging, targeted drug delivery and molecular engineering in complex biological environments.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.