Norbornene (NBE) Click Reagents

NBE (norbornene) click reagents are bioorthogonal labeling molecules that react rapidly and selectively with tetrazines through the inverse electron-demand Diels–Alder (IEDDA) reaction. As strained cyclic alkenes, norbornene reagents undergo efficient, copper-free conjugation under physiological conditions, forming stable covalent linkages with high specificity. NBE reagents offer excellent chemical stability and are widely used for labeling proteins, nucleic acids, cells, and other biomolecules in applications including bioconjugation, imaging, diagnostics, and targeted drug delivery.