KAT Ligation for Rapid and Facile Covalent Attachment of Biomolecules to Surfaces

29 March 2021, Version 1


The efficient and bioorthogonal chemical ligation reaction between potassium acyltrifluoroborates (KATs) and hydroxylamines (HAs) was used for the surface functionalization

of a self-assembled monolayer (SAM) with biomolecules. An alkane thioether molecule with one terminal KAT group (S-KAT) was synthesized and adsorbed onto a gold surface, placing a KAT

group on the top of the monolayer (KAT-SAM). As an initial test case, an aqueous solution of a hydroxylamine (HA) derivative of PEG (HA-PEG) was added to this KAT-SAM at room temperature to perform the surface KAT ligation. Quartz crystal microbalance with dissipation (QCM-D) monitoring confirmed the rapid attachment of the PEG moiety onto the SAM.

The covalent conjugation of PEG by amide-bond formation was established by complementary surface characterization methods including contact angle, ellipsometry, and X-ray photoelectron

spectroscopy (XPS). To test the applicability of this surface KAT ligation for the attachment of biomolecules to the surfaces, this KAT-SAM was subjected to the reaction with HA derivative of

protein. A HA-derivatized green fluorescent protein (HA-GFP) was added in dilute concentrations to the KAT-SAM under aqueous conditions and rapid protein attachment was observed in real-time by QCM. Despite the fact that such biomolecules have a variety of unprotected functional groups within their structures, the surface KAT reaction proceeded efficiently in a selective manner. Our results clearly demonstrate the versatile applicability of the KAT ligation for the covalent attachment of a variety of biomolecules onto surfaces under dilute and biocompatible

conditions to form stable, natural amide bonds.


self-assembled monolayer surfaces
orthogonal surface reaction
KAT ligation
amide bond formations
quartz crystal microbalance method
X-ray photoelectron spectroscopy analysis

Supplementary materials

Surface KAT SI 25Mar2021 final


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