Nanocrystalline diamond sensor targeted for selective CRP detection: an ATR-FTIR spectroscopy study

Per Ola Andersson*, Pernilla Viberg, Pontus Forsberg, Fredrik Nikolajeff, Lars Österlund, Mikael Karlsson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

Protein immobilization on functionalized fluorine-terminated nanocrystalline (NCD) films was studied by attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy using an immobilization protocol developed to specifically bind C-reactive protein (CRP). Using an ATR-FTIR spectroscopy method employing a force-controlled anvil-type configuration, three critical steps of the ex situ CRP immobilization were analyzed. First, the NCD surface was passivated by deposition of a copolymer layer consisting of polyethylene oxide and polypropylene oxide. Second, a synthetic modified polypeptide binder with high affinity to CRP was covalently attached to the polymeric film. Third, CRP dissolved in aqueous buffer in concentrations of 10–20 μg/mL was added on the functionalized NCD surface. Both the amide I and II bands, due to the polypeptide binder and CRP, were clearly observed in ATR-FTIR spectra. CRP amide I bands were extracted from difference spectra and yielded bands that agreed well with the reported amide I band of free (non-bonded) CRP in solution. Thus, our results show that CRP retains its secondary structure when it is attached to the polypeptide binders. Compared to previous IR studies of CRP in solution, about 200 times lower concentration was applied in the present study. [Figure not available: see fulltext.]

Original languageEnglish
Pages (from-to)3675-3680
Number of pages6
JournalAnalytical and bioanalytical chemistry
Volume408
Issue number14
DOIs
Publication statusPublished - 1 May 2016
Externally publishedYes

Keywords

  • Infrared spectroscopy
  • ATR-FTIR
  • Nanocrystalline diamond
  • CRP
  • Protein binders
  • Biosensor

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