Development and Application of New Platforms for Oligonucleotide and Protein Assays
Type of DegreePhD Dissertation
Chemistry and Biochemistry
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Sensitive and rapid detection of infectious disease is becoming very significant to improve human health. We have seen that the sensitive methods often required expensive, and sophisticated instruments. Biosensors are offering portable, cost-effective alternative to detect the clinically relevant biomarker, which also helps to design POC diagnosis. Several sensitive methods are being developed for biomarker detection. For POC systems required the methods which are inexpensive, sensitive, automated, and rapid that can serve to improve the health sector, especially in developing countries. One magnificent among these methods is the electrochemical biosensor. Electrochemiluminescence (ECL), the light-emitting process generated by electrochemical means, could transfer the electrochemical signal into light emission under specific applied potential. The ECL’s main characteristics and advantages are its benefit for biological assays; its high specificity and sensitivity; and its least hardware requirements (i.e., voltage source, electrodes, and light sensor, all of which can be miniaturized). All the combinations make ECL an ideal analytical detection method. The primary goal of this dissertation work is to develop a DNA-based electrochemical method for quantification of small molecules and ECL based aptasensors for large proteins, which is suitable for dip-and-read and POC diagnoses. Chapter 1 exhibits a detailed literature review on electrochemical DNA-based biomarker detection methods. Furthermore, a brief insight into electrochemiluminescence (ECL) history, mechanism, and application in bio-analytical sensing. Chapter 2 focuses on the electrochemical proximity assay (ECPA) on the glassy carbon electrode as a transducer and its optimization. After optimization, the experimental condition of the ECPA model system was illustrated. This work evaluates DNA fabrication on the glassy carbon electrodes, instrumentation issues, and illustrated to make ECPA DNA model measurement. Chapter 3 focuses on improving the redox moiety signal of methylene blue (MB) molecules by using catalytic molecules as K3[Fe (CN)6]. The electrochemical redox signal was increasing 30%, when the catalytic effect strategy was used. In Chapter 4 the large protein quantification approach is developed by exploiting the ECL, amplified ECL signal by using electroactive nanocomposites as Reduced graphene oxide- Tris(bipyridine)ruthenium (II) chloride composite (GO-Ru(bpy)32+. This method, in the future, should provide a generalizable platform for quantifying multiple proteins, peptides, or small molecules by a dip-and-read workflow, and this should promote future real-time measurements. Chapter 5 summarizes the findings of the research. The recommended future work of projects is stated.