Due to the bioorthogonality, high selectivity and exceptional reaction rates, the inverse-electron-demand Diels-Alder cycloaddition between tetrazines and strained alkene or alkyne dienophiles has been increasingly applied to the development of novel biomaterials. Adapting established procedures, I successfully synthesized various tetrazine (Tz) and trans-cyclooctene (TCO) derivatives and conjugated them to hyaluronic acid (HA), peptides and poly(ethylene glycol) (PEG). These conjugates have been used in various tissue engineering projects in our group.