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Label-free impedimetric immunosensor for ultrasensitive detection of cancer marker Murine double minute 2 in brain tissue

Biosensors and Bioelectronics
Publication Date
DOI: 10.1016/j.bios.2012.07.049
  • Mdm2
  • Cancer Biomarker
  • Brain Tissue
  • Cysteamine
  • Immunosensor
  • 1
  • 4-Phenylene Diisothiocyanate
  • Electrochemical Impedance Spectroscopy
  • Biology
  • Chemistry
  • Medicine


Abstract The detection of cancer biomarkers is as important tool for the diagnosis and prognosis of cancer such as brain cancer. Murine double minute 2 (MDM2) has been widely studied as prognostic marker for brain tumor. Here we describe development of a new sensitive label free impedimetric immunosensor for the detection of MDM2 based on cysteamine self assembled monolayers on a clean polycrystalline Au electrode surface. The amine-modified electrodes were further functionalized with antibody using homobifunctional 1,4-phenylene diisothiocyanate (PDITC) linker. The assembly processes of the immunosensor had been monitored with cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) techniques using Fe(CN)63−/4− solution as redox probe. The impedance changes upon binding of MDM2 protein to the sensor surface was utilized for the detection of MDM2. The increase in relative electron-transfer resistance (ΔR/R0%) values was linearly proportional to the concentration of tumor marker MDM2 in the wide dynamic range of 1pg/ml-1μg/ml. The limit of detection was 0.29pg/ml in phosphate buffer saline (PBS) and 1.3pg/ml in mouse brain tissue homogenate, respectively. The immunosensor showed a good performance in comparison with ELISA for the analysis of the MDM2 in the cancerous mouse brain tissue homogenates. Moreover, the immunosensor had a good selectivity against epidermal growth factor receptor (EGFR) protein, long-storage stability and reproducibility. It might be become a promising assay for clinical diagnosis and early detection of tumors.

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