Impedimetric, diamond-based immmunosensor for the detection of C-reactive protein

SENSORS AND ACTUATORS B-CHEMICAL

卷:157

Article

Vermeeren, V.^1,2  Grieten, L.^1,3  Vanden Bon, N.^1,2  Bijnens, N.^1,3  Wenmackers, S.^1,3  Janssens, S. D.^1,3  Haenen, K.^1,3,4  Wagner, P.^1,3  Michiels, L.^1,2 

[1] Hasselt Univ, B-3590 Diepenbeek, Belgium

[2] Transnat Univ Limburg, Sch Life Sci, Biomed Res Inst, B-3590 Diepenbeek, Belgium

[3] Transnat Univ Limburg, Sch Life Sci, Inst Mat Res, B-3590 Diepenbeek, Belgium

[4] IMEC Vzw, Div IMOMEC, B-3590 Diepenbeek, Belgium

关键词: Cardiovascular diseases;    C-reactive protein;    Immunosensor;    Impedance spectroscopy;    Nanocrystalline diamond;    Real-time detection;   

DOI  :  10.1016/j.snb.2011.03.037

来源: Elsevier

【 摘 要 】

The high prevalence of cardiovascular diseases (CVD) demands a reliable and sensitive risk assessment technique. In order to develop a fast and label-free immunosensor for C-reactive protein (CRP), a risk factor for this condition, anti-CRP antibodies were physically adsorbed to the hydrogen (H)-terminated surface of nanocrystalline diamond (NCD). An Enzyme-Linked ImmunoSorbent Assay (ELISA) reference technique showed that this was a suitable substrate for antibody-antigen recognition reactions. Electrochemical Impedance Spectroscopy (EIS) was used to electronically detect CRP recognition. The specificity of the immunosensor was demonstrated by incubation with CRP and plasminogen as reference molecule. A different impedance behavior was observed in real-time after CRP addition as compared to plasminogen addition: the impedance increased only during CRP incubation. Fitting the data showed that this corresponded with a decrease in capacitance of the molecular layer due to its increased thickness by specific CRP recognition. Sensitivity experiments in real-time showed a clear discrimination between 1 mu M,100 nM, and 10 nM of CRP after 10 min at 100 Hz. Since, 10 nM of CRP was still clearly distinguishable from buffer solution, our CRP-directed immunosensor prototype reaches a sensitivity that is within the physiologically relevant concentration range of this biomarker in healthy controls and CVD patients. Moreover, this prototype displayed real-time discriminating power between spiked and unspiked serum, and thus also shows its applicability in this biological matrix. (C) 2011 Elsevier B.V. All rights reserved.

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