Detection of folate binding protein with enhanced sensitivity using a functionalized quartz crystal microbalance sensor

Walter A. Henne, Derek D. Doorneweerd, Joonhyung Lee, Philip Low, Cagri Savran

Research output: Contribution to journalArticle

55 Scopus citations

Abstract

In this report, we describe the development of a quartz crystal microbalance biosensor for detection of folate binding protein (FBP). Using a simple folate-BSA conjugate adsorbed onto a Au-coated quartz sensor, a detection limit of 30 nM was achieved. Binding of FBP to the sensor surface could be blocked at concentrations as high as 1 μM with a 100-fold excess of folic acid, indicating the specificity of the folate-FBP interaction and the absence of nonspecific binding to the functionalized surface. Moreover, capture could be achieved in the presence of blood serum, making the assay amenable to the analysis of bodily fluids. Further signal enhancement based on an anti-FBP antibody and protein-A-coated gold nanosphere sandwich assay extended the detection limit to 50 pM (∼3 orders-of-magnitude improvement). Given the overexpression of FBP in certain malignancies and inflammatory disorders, we expect the methodology described here to be useful to detect FBP as a possible biomarker for disease diagnosis.

Original languageEnglish (US)
Pages (from-to)4880-4884
Number of pages5
JournalAnalytical Chemistry
Volume78
Issue number14
DOIs
StatePublished - Jul 15 2006

ASJC Scopus subject areas

  • Analytical Chemistry

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