Rapid Bioorthogonal Chemistry Turn-on through Enzymatic or Long Wavelength Photocatalytic Activation of Tetrazine Ligation

Abstract

Rapid bioorthogonal reactivity can be induced by controllable, catalytic stimuli using air as the oxidant. Methylene blue (4 μM) irradiated with red light (660 nm) catalyzes the rapid oxidation of a dihydrotetrazine to a tetrazine thereby turning on reactivity toward trans-cyclooctene dienophiles. Alternately, the aerial oxidation of dihydrotetrazines can be efficiently catalyzed by nanomolar levels of horseradish peroxidase under peroxide-free conditions. Selection of dihydrotetrazine/tetrazine pairs of sufficient kinetic stability in aerobic aqueous solutions is key to the success of these approaches. In this work, polymer fibers carrying latent dihydrotetrazines were catalytically activated and covalently modified by trans-cyclooctene conjugates of small molecules, peptides and proteins. In addition to visualization with fluorophores, fibers conjugated to a cell adhesive peptide exhibited a dramatically increased ability to mediate contact guidance of cells.

Exploring the Condensation Reaction between Aromatic Nitriles and Amino Thiols To Optimize In Situ Nanoparticle Formation for the Imaging of Proteases and Glycosidases in Cells

“…[1] Recently,e fforts have been made to modulate the reactivity of bioorthogonal reactions by light. [10] Very few reactions reported to date can be activated by an enzyme.F or example,F ox and co-workers reported horseradish-peroxidase-activated oxidation of dihydrotetrazine to tetrazine [11] and Laughlin and co-workers reported the enzymatic uncaging of as teric blocking group on cyclopropene. [12] However,n oe nzyme-activated bioorthogonal reactions have been used in vivo.…”

ortho‐Quinones and Analogues Thereof: Highly Reactive Intermediates for Fast and Selective Biofunctionalization

“…A number of reviews have summarized bioconjugation strategies based on either native reactive amino acids, introduction of unnatural amino acid tags for selective coupling, chemical ligation strategies or chemoenzymatic conversions . However, novel approaches to functionalize natural amino acid residues continue to be discovered, including strategies regarding labelling inside living cells and strategies entailing a selective preactivation step …”

Chemical synthesis of biomimetic hydrogels for tissue engineering

“…199 Alternatively, polymer fibers carrying latent dihydrotetrazines were catalytically activated to tetrazine and covalently modified by TCO conjugates of small molecules, peptides and proteins. 200 In a related project, polymer fibers carrying latent dihydrotetrazines were catalytically activated to tetrazine and covalently modified by trans -cyclooctene conjugates of small molecules, peptides and proteins. In addition to visualization with fluorophores, fibers conjugated to a cell adhesive peptide exhibited a dramatically increased ability to mediate contact guidance of cells.…”