Bi-cell surface plasmon resonance detection of aptamer mediated thrombin capture in serum

Rinosh Joshua Mani, Roman G. Dye, Timothy A. Snider, Shaopeng Wang, Kenneth D. Clinkenbeard

Research output: Contribution to journalArticle

24 Scopus citations

Abstract

The serine protease coagulation factor thrombin functions primarily in hemostasis, but is also involved in atherosclerosis, thromboembolic disease, cancer and inflammatory disease. Direct measurement of coagulation proteins including thrombin in plasma samples poses a significant challenge because of lack of specific probes and low thrombin concentrations. In addition, high plasma protein concentrations in samples can result in high backgrounds. These challenges were overcome using a bi-cell surface plasmon resonance (SPR) spectrometer with an immobilized thrombin aptamer to measure thrombin in samples passed through a low volume flow cell. For thrombin in Tris-EDTA buffer, the limit of detection (LOD) was 25. nM. Coefficient of variation (CV) for detection of 50. nM was 12.2% and 12.4% for intra and inter-day measurements respectively. This detection was specific for both thrombin aptamer and for thrombin. Using serum samples spiked with thrombin, the LOD was 50. nM with a linear range of detection from 50. nM to 200. nM. However use of serum samples was associated with consistent, low-level background drift. The contributions of nonspecific protein absorption onto the sensor surface and sample flow speed were assessed, and strategies to reduce this background drift were explored. We conclude that the bi-cell SPR platform with an aptamer capture probe can be employed as a highly sensitive real-time, label-free biosensor for the detection of coagulation factors in plasma samples.

Original languageEnglish (US)
Pages (from-to)4832-4836
Number of pages5
JournalBiosensors and Bioelectronics
Volume26
Issue number12
DOIs
StatePublished - Aug 15 2011

Keywords

  • Aptamer
  • Bi-cell surface plasmon resonance spectrometer
  • Serum
  • Thrombin

ASJC Scopus subject areas

  • Biotechnology
  • Biophysics
  • Biomedical Engineering
  • Electrochemistry

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