Towards a biosensor immunoassay of protein-bound isopeptides in human plasma

Anna Bergstrand*, Ismail Ceylan, Gerard Quash, Magnus Nydén, Krister Holmberg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


This study demonstrates that synthetic isopeptides formed on BSA can be quantitatively analyzed by a surface plasmon resonance-based biosensor method. A monoclonal IgM antibody 81D4, that reacts with the synthetic isopeptide and also with the natural isopeptide cross-link in D-dimer (but not with its non-cross-linked fibrin monomer), was covalently immobilized to a carboxymethylated dextran surface, a CM5 surface. Its immunocapturing efficiency was found to be good. The affinity of the interaction between the monoclonal 81D4 and the synthetic isopeptide was estimated to approximately 4 × 10-7 M. Good reactivity was also observed when human plasma spiked with this isopeptide was used as test solution. Cross-linked D-dimer in the plasma of patients is a marker of disseminated intravascular coagulation (DIC) which occurs late in sepsis. This biosensor method has the potential to be developed into a rapid sensitive assay for measuring the level of natural isopeptide cross-links in proteins in the plasma of patients with a suspected diagnosis of sepsis.

Original languageEnglish
Pages (from-to)150-153
Number of pages4
JournalColloids and Surfaces B: Biointerfaces
Issue number1
Publication statusPublished - 1 Oct 2008
Externally publishedYes


  • SPR
  • Surface plasmon resonance
  • Isopeptides
  • DIC
  • Disseminated intravascular coagulation
  • Sepsis
  • Optical biosensor assay


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