Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5031424 | Biosensors and Bioelectronics | 2017 | 7 Pages |
Abstract
We have demonstrated label-free and real-time detection of prostate specific antigen (PSA) in human serum using silicon nanowire field effect transistors (NW FETs) with Schottky contacts (Si-Ti). The NW FETs were fabricated from SOI material using high-resolution e-beam lithography, thin film vacuum deposition and reactive-ion etching processes eliminating complicated processes of doping and thermal annealing. This allowed substantial simplifying the transistors manufacturing. A new method for covalent immobilization of half-fragments of antibodies on silicon modified by 3-glycidopropyltrimethoxysilane with thiol groups and 5Â nm gold nanoparticles (GNPs) was established. NW FETs functionalized by GNPs revealed extremely high pH sensitivity of 70Â mV/pH and enhanced electrical performance in the detection of antigen due to enhanced surface/volume ratio, favorable orientation of antibody active sites and approaching the source of the electric field close to the transistor surface. Si NWFETs were applied for quantitative detection of PSA in a buffer and human serum diluted 1/100. Response time was about 5-10Â s, and analysis time per sample was 1Â min. The limit of PSA detection was of 23Â fg/mL, concentration range of 23Â fg/mL-500Â ng/mL (7 orders of magnitude). The PSA concentrations determined by the NW FETs in serum were compared with well-established ELISA method. The results matched well with the correlation coefficient of 0.97.
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Analytical Chemistry
Authors
Galina Presnova, Denis Presnov, Vladimir Krupenin, Vitaly Grigorenko, Artem Trifonov, Irina Andreeva, Olga Ignatenko, Alexey Egorov, Maya Rubtsova,