Propargyl-PEG1-SS-alcohol is a Click Chemistry-ready crosslinker containing a propargyl group, a hydroxyl group and a cleavable disulfide bond. The propargyl groups can react with azide-bearing compounds or biomolecules via copper catalyzed azide-alkyne Click Chemistry to yield stable triazole linkages. The hydroxyl group enables further derivatization or replacement with other reactive functional groups.