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iDEA: Drexel E-repository and Archives > Drexel Theses and Dissertations > Drexel Theses and Dissertations > Use of piezoelectric-excited millimeter-sized cantilever (PEMC) sensors for DNA-Based detection of pathogens and disease conditions

Please use this identifier to cite or link to this item: http://hdl.handle.net/1860/3468

Title: Use of piezoelectric-excited millimeter-sized cantilever (PEMC) sensors for DNA-Based detection of pathogens and disease conditions
Authors: Rijal, Kishan
Keywords: Chemical Engineering;Biosensors;Piezoelectric devices
Issue Date: 15-Apr-2011
Abstract: In this study, Piezoelectric-Excited Millimeter-Sized Cantilever (PEMC) sensors were used to detect pathogens and disease conditions using DNA-based detection technique. Using Stx-2 gene as a unique identifier, the model pathogen E. coli O157:H7 was detected using a simplified and rapid genomic DNA extraction method (30 min) in both buffer and proteinous complex matrix at ~2,000 pathogens per mL. Single Nucleotide Polymorphism (SNP) of DNA of length 10 to 60 nt were detected via nucleic-acid hybridization at 1 femtomolar concentration. Synthetic single stranded DNA, 10 to 288 bases long were detected by hybridization. For the first time, Taq-polymerase based extension of captured DNA was performed on the cantilever sensor thus increasing hybridized mass by ~2.2 pg. The PEMC sensor showed high specificity in detecting complementary DNA in presence of 10,000 times higher concentration noncomplementary DNA strands. Using antibody-antigen assay, E. coli O157:H7 was detected at 10 cells/mL and developed a protocol for regeneration of the sensor surface for multiple uses. Another significant result is the measurement of alkanethiol chemisorption on Au<111> coated sensor surface at 1 femtomolar. At higher alkanethiol concentrations the sensor responses were proportionately, but non-linearly, higher. However, the responses to C4, C8, C11, C16 and C18 alkanethiols at 1 mM were linearly proportional. We report for the first time that, once the Au-surface is equilibrated at 1 pM, further chemisorption at a lower concentration does not take place, even though over 99% of adsorption sites is vacant.
URI: http://hdl.handle.net/1860/3468
Appears in Collections:Drexel Theses and Dissertations

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