The dissertation was defended at the public meeting of the Dissertation Defense Council of the Scientific Field of Materials Engineering in the SRA-I Hall of Vilnius Gediminas Technical University at 2 p.m. on 6 June 2024.
Immunosensors are renowned for their high sensitivity and specificity, making them commonly used in diagnostics. Immunosensors are utilized to identify cancerous conditions, conduct histological studies, and as a tool to help control the spread of viral diseases. However, creating quantitative immunological sensors often involves challenges such as the denaturation of the biological recognition element or label, insufficient signal strength, or the need for expensive equipment to convert the signal into a measurable one. The dissertation focuses on the development of a quantitative electrochemical immunosensor by creating a new method to detect labeled antibodies and replacing traditional labels with denaturation-resistant nanoparticles. The dissertation aims to create a prototype of a quantitative electrochemical immunosensor using a metal-biomaterial composite as the recognition element and scanning impedance microscopy for signal conversion. The introduction presents the problem formulation, the object, and the relevance of the dissertation. It describes the research methodology, scientific novelty, defending statements, and the structure of the dissertation. The first chapter provides an overview of immunosensors. It discusses biosensors and focuses on electrochemical immunosensors, their history, and types. The use of nanomaterials, i.e., gold, platinum, reduced graphene, and conductive polymers, in immunosensors is described. The working principles of scanning electrochemical microscopy and electrochemical impedance spectroscopy, as well as their application in immunological sensors, are analyzed. Surface characterization methods are also briefly discussed. The second chapter reviews the methods and materials used, solution preparation, sample immobilization, and electrode modification protocols. The construction of electrochemical cells and the parameters used are briefly described. This chapter also outlines the mathematical models used to determine reaction kinetics and surface parameters. The third chapter presents the results of experimental studies on the immunological sensor. It details the advantages and disadvantages of scanning electrochemical impedance microscopy, modifications to ultramicroelectrodes to address high resistance encountered, and the evaluation of a prototype quantitative immunosensor based on gold nanoparticle-labeled antibodies and scanning electrochemical impedance microscopy as the signal converter. The dissertation’s results have been published in seven scientific articles in journals indexed in the Clarivate Analytics Web of Science database. The dissertation topic has been presented at eleven international conferences.
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