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Title:	New urea and DNA biosensors constructed based on nanomaterials
Authors:	Muawia (Moh'd-Ali) Salameh Alqasaimeh (P44095)
Supervisor:	Lee Yook Heng, Prof. Dr.
Keywords:	New urea DNA biosensors Nanomaterials Universiti Kebangsaan Malaysia -- Dissertations
Issue Date:	4-Feb-2014
Description:	Four different types of nanomaterials: (1) silica-gel nanoparticles (SiO2 NPs), (2) Polyaniline NPs (PANI NPs), (3) acrylate-Co-N-acryloxysuccinimide microspheres (nBA MPs) and (4) metallic sulfides/or oxides NPs (MNPs) were studied for their potential in the development of new biosensors. New urea or DNA biosensors based on these nanomaterials were designed and their performance investigated. The studies involved different nanomaterial preparation, modifications, characterization and biosensors designs. In the case of urea biosensors, the use of different immobilization methods for nanomaterials and urease as analyte recognition were studied. Different transducers (optical or electrochemical) based on PANI NPs, chromoionophore and nafion composites for the urea biosensors were also examined. In the case of DNA biosensors, metallic sulfides/or oxides NPs caped with polyvinylpyrrolidone (PVP), (MNPs\\PVP) or without capping (MNPs) were attempted for biosensor construction. An optical urea biosensor based on silica NPs immobilized with urease and chromoionophore showed a linear response range to urea of 50-500 mM with a lower detection limit of 20 mM and the biosensor response time was 9 min. The potentiometric urea biosensor based on urease-nBA MPs and PANI NPs/nafion composites on Ag/AgCl screen-printed electrode (Ag/AgCl SPE) (Biosensor 25) demonstrated sensitivity of -26.9 mV/mM in the range 8.6–14.6 mM urea with response time of 8 min. Another potentiometric urea biosensor based on urease-nBA MPs and PANI NPs without nafion on Ag/AgCl SPE (Biosensor 24) showed sensitivity -1.4 mV/mM in the range of 24.7–130.8 mM urea with response time of 1.5 min. In general, biosensors 25 & 24 showed no clear interference from most common cations studied, except for biosensor 25, which could be affected by high concentrations of ammonium ions. Using the redox intercalator anthraquinone monosulfonic acid (AQMS), an amperometric DNA biosensor was constructed based on ZnS(ethylenediamine)/PVP NPs. Under optimum conditions, the biosensor was selective to complementary DNA (cDNA) and demonstrated a linear response in the range of 1.5-1.9 μM (sensitivity 3.5 μA/μM) and 1.9-2.0 μM (sensitivity 21.6 μA/μM) cDNA. The detection limit of the biosensor was 1.5 μM cDNA. In conclusion, the nanomaterials employed in this study has been successfully used for the development of new urea and DNA biosensors.,PhD
Pages:	253
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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