Theses & Dissertations

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https://hdl.handle.net/20.500.14170/2003

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Browsing Theses & Dissertations by Subject "Biosensing"
  • Publication
    Nano-diagnostics-on-chip: an innovative approach of quantifiable multi-analyte via tripartite polysilicon nanogap for prenatal care
    ( 2016)
    Sharma Rao A/L Balakrishnan
    “Everything grows rounder and wider and weirder, and I sit here in the middle of it all and wonder who in the world you will turn out to be”– Carrie Fisher. A quote portraying the dreams and emotions of every mother who wished to provide good health and life for the unborn. Current thesis has been motivated by the importance of providing early stage diagnosis and preventive healthcare to mother and child, which is one of the prime goals focused by the United Nation in Millennium Development Goals in 2015. Key importance has been given to the areas that have inadequate maternal healthcare, as rising numbers seen in maternal and fetal mortality and morbidity. Providing a rapid test result near patient is necessary to undertake safety precautions as well as reducing the patient’s anxiety of waiting time for the results. Herein, a novel, point-of-care nano-diagnostic device based on lab-on-chip biosensing is demonstrated using nanostructured polysilicon nanogap electrode, which assists a single drop fluid delivery by tripartite microchannels for multi-analyte diagnosis called ‘Prenatal-Care-on-Chip’. Polysilicon semiconducting material was chosen as the electrode for nanogap structure, and fine-tuned by varying deposition period and annealing process to facilitate a proper biosensing surface. The designing and fabrication of the lab-on-chip were performed in-house via conventional lithography and nanogap electrode structures by size reduction and expansion technique. Soft-lithography was employed to create microchannels by mold-casting. Another important aspect is the surface functionalization on the lectrode, which is crucial for selectivity and reliability of the biosensor. Various chemical modifications were examined in this study to analyze the performance (suitability, compatibility and sensitivity) of bio-receptor towards multi-analyte detection. Most crucial and healthcare demanding targets (analytes) for prenatal care were examined, such as Human Chorionic Gonadotropin for pregnancy assessment and Glucose for Gestational Diabetes Mellitus. Both prepared and clinically tested urine and saliva samples were investigated and analyzed by morphological, optical, structural and electrical studies to evaluate performance of the biochip.
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