Detection Of Cardiac Biomarkers In Acute Myocardial Infarction Using Modiifed Lateral Flow Immunoassay

Annually, several million patients seek care in the emergency room because of chest pain or other symptoms suggesting acute coronary syndrome, but only10-15%subsequently develop an acute myocardial infarction (AMI). Evaluation of patients with symptoms suggestive of AMI in the emergency room is time-consuming and expensive, and it often results in equivocal diagnosis. Thus, the rapid and accurate evaluation of patients presenting with symptoms suggestive of AMI is of great clinical relevance. The implementation of point-of-care testing (POCT) has allowed a reduction of the preanalytical phase correlated to the transport and processing of samples to achieve the goal.The development of the rapid lateral flow immunoassay (LFIA) is the result of convergence of several threads that can be traced back to the1950s. LFIAs represent a well-established and very appropriate technology when applied to a wide variety of point-of-care (POC) or field use applications. The advantages of the LFIA system are well known as ease of use-minimal operator-dependent steps and interpretation; high sensitivity, specificity, good stability and market acceptance-minimal education required for users and regulators. LFIAs have achieved broad penetration in a variety of markets such as medical diagnosis and therapeutic monitoring, forensic science, environmental monitoring and food safety. Despite desirable features of real performance, LFIAs have suffered from performance limitations in the diagnosis of AMI, most notably sensitivity and specificity.Over the last several decades, the gold nanoparticles (AuNPs) with unique combination of chemical and physical properties are the subject of intensive studies and applications in many fields, especially in biology and medicine. To date, the ever increasing diversity of published examples has included genomics and biosensors, immunoassays and clinical chemistry, photothermolysis of cancer cells, targeted delivery of drugs and antigens, and optical bio imaging of cells and tissues with state-of-the-art nanophotonic detection systems. The main parts of the thesis were given to the development of two novel, rapid and high-sensitivity dipsticks for single detection of C reactive protein and simultaneous detection of high-sensitivity cardiac troponin I (hs-cTnl) and myoglobin that take the advantage of the biotin-streptavidin binding system and double gold nanoparticles with different sizes as label and the preliminary evaluation of the LFIA for simultaneous detection of hs-cTnl and myoglobin. Although the primary goal of my thesis was to design and construct the high-sensitivity biosensors for POC detection of AMI, I have started my work with the synthesis and investigation of gold nanoparticles by the reduction of metal salts in citrate solutioa This nanoparticle will be of great importance and a key cornerstone of my research in the study of LFIAs.The present doctorate thesis is structured in seven chapters, as follows:Chapter1contains a general introduction about AMI and highly valuable biomarkers for the early diagnosis of this cardiovascular disease; the synthesis, physical and chemical properties and applications of gold nanoparticles and their use as label in biosensors. At the same chapter are described the application of LFIA in bio medicine and the previous assembly methods of LFIA.Chapter2describes the method for preparation and characterization of GNPs.Chapter3focuses on the design and construction of a high-sensitivity LFIA for single detection of high-sensitivity C reactive protein.Chapter4focuses on the design and construction of a high-sensitivity LFIA for simultaneous detection of hs-cTnI and myogfobinChapter5describes the preliminary evaluation of the LFIA for simultaneous detection of hs-cTnI and myoglobin.Chapter6summarizes the general conclusions of the thesis and put forward the proposals for future studies.Chapter7reviews the AuNPs and LFIAs which is divided in two parts:The first part reviews elaborately the synthesis, physical and chemical properties and applications of GNPs and their use as label in biosensors.The second part reviews thoroughly the application of LFIAs in biomedicine. This part also describes previous assembly methods of lateral flow immunoassay.The final annex shows the publications and patent that resulted from this thesis and acknowledgements to people, who have been involved in encouragement, guidance and support from the initial to the final level enabled me to get my PhD. degree.