DBCO-PEG24-NHS ester

DBCO-PEG24-NHS ester is a strained-alkyne click chemistry reagent combining a dibenzocyclooctyne (DBCO) moiety with a long, hydrophilic PEG24 spacer and an NHS ester for amine-reactive functionalization. This design makes it widely used for stable copper-free strain-promoted azide–alkyne cycloaddition (SPAAC) workflows, where the PEG spacer helps improve solubility and reduces nonspecific interactions. The NHS ester enables straightforward conjugation to primary amines on proteins, peptides, antibodies, and other amine-bearing biomolecules, providing a convenient entry point to DBCO-functionalized probes and materials.

1. Protein And Antibody Labeling

DBCO-PEG24-NHS ester is commonly used to generate DBCO-functional antibody and protein conjugates for downstream SPAAC labeling with azide-bearing imaging agents, affinity tags, or reporter molecules. The NHS ester reacts with lysine side-chain amines under standard bioconjugation conditions, while the PEG24 spacer supports colloidal stability and helps maintain accessibility of the DBCO group during conjugation and storage. This reagent is frequently selected in research workflows that require controlled surface presentation of click handles on biomolecules for consistent labeling density and reduced aggregation.

2. Surface Functionalized Biomaterials

DBCO-PEG24-NHS ester is used to introduce SPAAC-reactive DBCO groups onto amine-containing biomaterial surfaces, including polymer films, hydrogel matrices, and functional coatings derived from amine-rich chemistries. The PEG24 linker improves compatibility with aqueous environments and can mitigate steric effects that otherwise limit click coupling efficiency on heterogeneous materials. After immobilization, azide-functional partners can be coupled via copper-free click chemistry to build modular biomaterial platforms such as functionalized scaffolds for biosensing, cell-interaction studies, and multicomponent surface assemblies.

3. Fluorescent And Imaging Probe Construction

DBCO-PEG24-NHS ester supports the preparation of fluorescent and molecular imaging probes by enabling DBCO installation onto amine-bearing targeting ligands, carrier proteins, or scaffold molecules prior to click attachment of azide-tagged reporters. The long PEG spacer is particularly useful when probe conjugates must remain soluble and minimize nonspecific adsorption in complex buffers, which is often critical for imaging reagent handling and consistent signal generation across labeling batches. This approach is widely adopted in chemical biology and imaging tool development to create modular probe sets that can be rapidly reconfigured by swapping azide partners.

4. Multivalent Targeting Conjugates

DBCO-PEG24-NHS ester is frequently employed to build multivalent conjugates where multiple azide-bearing components are appended to a single DBCO-functional backbone. By coupling the NHS ester to amine-rich targeting constructs, researchers can create platforms for sequential or parallel SPAAC assembly, supporting the generation of higher-avidity binding reagents and structured multicomponent libraries used in assay development and molecular interaction studies. The PEG24 spacer helps preserve the accessibility of the DBCO handle, which is important for achieving reproducible conjugation outcomes when multiple click events are performed on the same construct.