DBCO-PEG2-NHS ester | CAS 2585653-12-7

DBCO-PEG2-NHS ester is a difluorobenzocyclooctyne (DBCO) functionalized polyethylene glycol (PEG) NHS ester designed for strain-promoted azide–alkyne cycloaddition (SPAAC) workflows and efficient amine-reactive labeling. The reagent combines a stable NHS ester handle for coupling to primary amines with a cyclooctyne click group that enables bioorthogonal conjugation to azide-bearing partners under mild conditions. Its PEG spacer improves solubility and reduces steric constraints, making it widely used in probe and biomaterial functionalization where controlled attachment of DBCO to proteins, peptides, and polymer surfaces is required.

1. Protein And Peptide Labeling

DBCO-PEG2-NHS ester is commonly used to install DBCO onto proteins and peptides via NHS ester reactivity with lysine side chains and N-terminal amines, generating azide-reactive bioconjugates for downstream click coupling. Researchers frequently employ this reagent to prepare antibody fragments, enzyme conjugates, and receptor-binding ligands that are later linked to azide-functional imaging agents, affinity tags, or multivalent scaffolds. The PEG2 spacer helps maintain colloidal stability and can improve accessibility of the DBCO moiety during subsequent SPAAC reactions, which is particularly valuable when conjugating in complex labeling buffers or when targeting bulky azide-bearing constructs.

2. Surface and Biomaterial Functionalization

DBCO-PEG2-NHS ester is well suited for introducing click-ready DBCO groups onto amine-containing biomaterial surfaces, including PEGylated coatings, hydrogel matrices, and functionalized polymer films that present accessible primary amines. In materials and biomaterials research, the NHS ester provides a convenient route to immobilize DBCO onto substrates prior to coupling with azide-bearing biomolecules, such as cell-adhesion peptides, growth factor mimetics, or fluorescent reporters. This approach supports modular assembly of patterned or layered materials where spatially controlled click attachment is achieved by reacting the surface-bound DBCO with azide partners.

3. Multivalent Probe Construction

DBCO-PEG2-NHS ester is frequently used to build multivalent chemical probes by first generating DBCO-functional intermediates on a carrier (for example, a protein scaffold, dendrimer-like polymer, or polymer backbone) and then performing SPAAC coupling to azide-functional reporters. The PEG2 linker contributes to improved solubility and spacing between the conjugation point and the DBCO handle, which can be important for preserving binding or recognition behavior of the azide-derived components used to generate imaging or detection reagents. This two-step design is widely adopted in chemical biology for assembling probe libraries with defined valency and for swapping azide-bearing modules without re-optimizing the initial amine-labeling step.

4. Diagnostic Reagent Development

DBCO-PEG2-NHS ester is used in the development of diagnostic research reagents that rely on modular conjugation between DBCO-bearing capture or labeling components and azide-functional detection elements. Laboratories often prepare DBCO-tagged affinity reagents, such as biotin-like binders or antibody-derived binders, by NHS ester coupling to amines, followed by SPAAC attachment to azide-bearing fluorophores, enzyme substrates, or particulate labels used in assay workflows. The reagent’s PEG spacer and NHS chemistry facilitate consistent handle installation on amine-rich reagents, enabling streamlined generation of assay-ready conjugates for reagent screening and method development.