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Type: Theses
Title: Development of optical microchip sensor for biomolecule detection
Author: Nemati, Mahdieh
Issue Date: 2018
School/Discipline: School of Chemical Engineering
Abstract: Optical sensors play vital roles in many applications in today’s world. Photonic technologies used to design and engineer optical sensing platforms can provide distinctive advantages over conventional detection techniques. For instance, when compared to electronic and magnetic sensing systems, optical sensors require physically smaller equipment and have the capability for delivering more analytical information (e.g. spectroscopic signatures). In addition, demand for low-cost and portable bio-analyte detections is a growing area for applications in healthcare and environmental fields. Among other factors to achieve reliable results in terms of selectivity and sensitivity is key for the detection of bio-analytes with analytical relevance. Commonly used bio-analytical techniques (e. g. high performance liquid chromatography) have been appropriately designed based on qualitative and quantitative analysis. However, the requirement of expensive equipment, and complexity of procedures (e.g. biomolecule labelling, calibrations, etc.) restrict the board applicability and growth of these techniques in the field of biosensing. Optical sensors tackle these problems because they enable selective and sensitive detection of analytes of interest with label-free, real-time, and cost-effective processes. Among them, optical interferometry is increasingly popular due label-free detection, simple optical platforms and low-cost design. An ideal substrate with high surface area as well as biological/chemical stability against degradation can enable the development of advanced analytical tools with broad applicability. Nanoporous anodic alumina has been recently envisaged as a powerful platform to develop label-free optical sensors in combination with different optical techniques. This thesis presents a high sensitive label-free biosensor design combining nanoporous anodic alumina (NAA) photonic structures and reflectometric interference spectroscopy (RIfS) for biomedical, food and agricultural applications. NAA is a suitable optical sensing platform due to its optical properties; a high surface area; its straightforward, scalable, and cost-competitive fabrication process, and its chemical and mechanical stability towards biological environments. Our biosensor enables real-time screening of any absorption and desorption event occurring inside the NAA pores. A proper selection of bio-analytes were able to be detected using this platform which offers unique feature in terms of simplicity and accuracy. The most relevant components of this thesis are categorised as below: 1. Self-ordered NAA fabrication and detection of an enzymatic analyte as a biomarker for cancer diagnosis: Fabrication of NAA photonic films using two step electrochemical anodization and chemical functionalisation. Detection of trace levels of analyte enzyme and its quantification by selective digestion. The NAA photonic film with the enzyme acts as a promising combination for a real-time point-of-care monitoring system for early stages of disease. 2. NAA rugate filters used to establish the binding affinity between blood proteins and drugs: Design, fabrication, and optimisation of NAA anodization parameters using sinusoidal pulse anodization approach (i.e. anodization offset and anodization period) to produce rugate filter photonic crystals that provide two comparative sensing parameters. Establishment of highly sensitive and selective device capable for drug binding assessments linked to treating a wide range of medical conditions. 3. NAA bilayers and food bioactive compound detection: Design, fabrication, and optimisation of NAA anodization parameters (i.e. anodization time and number of anodization steps) to obtain NAA bilayered photonic structures that display the effective response of NAA geometry with different types of nano-pore engineering. The photonic properties of the NAA bilayer were studied at each layer of nano-structure under specific binding of human serum albumin and quercetin as target agent. 4. Single nucleotide polymorphism (SNP) detection: The design and implementation of a Ligation-Rolling Circle Amplification assay to detect a single nucleotide polymorphism associated with insecticide resistance in a pest beetle species, Tribolium castaneum. This proof-of-concept SNP detection assay has the potential to provide a method compatible with a biosensor platform such as NAA. This demonstrates the first step towards the potential development of a genotyping biosensor, and a real-world application of insect insecticide resistance monitoring. The results presented in this thesis are expected to enable innovative developments on NAA sensing technology that could result in highly sensitive and selective detection systems for a broad range of bio-analytes detections.
Advisor: Losic, Dusan
Hill, Kelly
Dissertation Note: Thesis (Ph.D.) (Research by Publication) -- University of Adelaide, School of Chemical Engineering, 2018
Keywords: Research by publication
nano material
Provenance: This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at:
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