University of Twente Student Theses


Nanomechanical sensing of hypermethylated DNA for the detection of bladder cancer

Birkhölzer, Y.A. (2015) Nanomechanical sensing of hypermethylated DNA for the detection of bladder cancer.

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Abstract:This thesis explores a novel nanomechanical DNA sensor that is being developed for the detection of bladder cancer. The proposed device comprises an array of microcantilevers, whose resonance frequencies change upon molecular adsorption. This shift in resonance frequency is the working principle of the novel device. Laser Doppler vibrometry is used to measure the resonance frequency of the thermally actuated cantilevers. By functionalizing the cantilever surface with thiolated single-stranded DNA, the cantilever sensor is made sequence-specific for the hybridization of complementary DNA strands. New devices are fabricated and characterized by ellipsometry, scanning electron microscopy and electron dispersive X-ray spectroscopy. Surface functionalization is studied with fluorescence microscopy and X-ray photoelectron spectroscopy. A DNA concentration of 1 μM in TE-buffer is readily detected and distinguished from non-specific adsorption. The sensor performance is drastically improved by reducing nonspecific interactions via backfilling with a PEG-Silane anti-fouling agent prior to DNA hybridization. Current theoretical models for mass, stress, and stiffness effects on cantilever resonance frequencies are numerically evaluated but cannot explain the large magnitude of sensor response found experimentally.
Item Type:Essay (Bachelor)
Faculty:EEMCS: Electrical Engineering, Mathematics and Computer Science
Subject:51 materials science
Programme:Advanced Technology BSc (50002)
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