@phdthesis{oai:niigata-u.repo.nii.ac.jp:02000453, author = {Pothipor, Chammari}, month = {2022-05-10, 2022-05-10}, note = {The surface plasmon resonance (SPR)-based sensor offers direct, label-free, real-time, and quantifiable detection of the biomolecular interactions by measuring near a thin metal film surface or refractive index change. This technique provide opportunity for cost-effective and fast detection of the target molecules. In addition, electro-optical techniques combine electrochemical and optical data present more precise and detailed measurements that provide understandings of molecular function and structure. This thesis is divided in three result chapters. Chapter 2 have two sections to description the development of SPR and electrochemical-surface plasmon resonance (EC-SPR)-based biosensors for detection of immunoglobulin type G (IgG). In the first section, a simple and successful technique for constructing an electrochemical-surface plasmon resonance immunosensor (EC-SPR)-based on poly(2-aminobenzylamine)/graphene oxide (P2ABA/GO) is demonstrated. The GO composited with P2ABA is deposited on a gold surface by cyclic voltammetry CV technique with a potential range of -0.2 to 1.1 V for 2 cycles at a scan rate of 20 mV/s. After electropolymerization of the composite film, a shift of SPR dip is observed. The enhancement of IgG detection on P2ABA/GO/gold film is obtained compared with P2ABA film. The GO has a larger number of functional groups for example, hydroxyl, carboxylic, and epoxides, than the gold electrode. To interact with the target molecule, the surface functionality of GO, which contains epoxy/hydroxyl groups in the basal plane and carboxylic acid groups at the edge plane, can be used. The concentration dependence exhibits a linear relationship with human IgG in the range from 1.0 to 10 µg/mL and the lowest detection limit (LOD) of 0.95 µg/mL, suggesting good device performances in the detection of human IgG. In section 2, the incorporation of graphene oxide-poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (GO/PEDOT/PSS) thin film on gold-coated high reflective index substrate is employed IgG by EC-SPR technique. The EC-SPR immunosensors are strong bioanalysis instruments that are label-free and have high stability, specificity, and sensitivity for measuring antigens binding to antibodies fixed on the SPR sensor surface. The GO/PEDOT/PSS film is prepared by in situ electropolymerization on a gold electrode and subsequently chemical modified carboxylic terminal group of GO by surface-confined ester reaction of EDC/NHS. The human IgG selectively reacted with the functionalized substrate by covalent binding of amide coupling reaction. The number of binding site for immunoreaction of the GO/PEDOT/PSS film is increased by applied potential as the incorporate polymer film is swollen and surface area of the film is increased under doping. The significant increase in the binding of human IgG molecules on the functionalized substrate state is observed when the applied potential is increased. In compared to an open circuit and applied potentials in the ranging from -1.0 to 0.5 V, the EC-SPR immunosensor has the highest sensitivity when applied potential at 0.5 V. The SPR intensity exhibits linearity in the concentration of IgG from 1.0 to 10 µg/mL with a LOD of 0.35 µg/mL. In addition, Chapter 3 has two parts. The first part of this chapter described a facile and label-free approach for constructing high-sensitivity, GO-based TSPR biosensors with high precision and accuracy over important analyte measurement ranges. The binding phenomena between proteins IgG and anti-IgG/GO films is detected using the TSPR method. TSPR is a surface-sensitive optical technique for detecting biomolecular interactions close to sensor interfaces. It provides real-time and label-free analytical detection by the changes of interfacial refractive index associated with any specific binding interface after biomolecule immobilized on a sensor surface. The application of TSPR in biosensors offers a unique potential because to its rapid and simultaneous analysis without labeling, accurate detection, and low LOD. In this section 2, we demonstrate transmission surface plasmon resonance-imaging (TSPR-i) with a microfluidic 3-channel cell. Silver nanoparticles (AgNPs) are deposited with poly (diallydimethylammonium chloride) (PDADMAC) and poly (sodium 4-styrenesulfonate) (PSS) using layer-by-layer (LbL) technique on gold thin film grating/substrate surfaces. TSPR-i technique is used to study the effect of localized surface plasmon resonance (LSPR) from plasmonic AgNPs on the gold-grating/dielectric interface for the signal enhancement of creatinine detection. After the deposition of AgNPs on the gold grating substrate, a decrease of TSPR-i intensity is observed. 10 mM creatinine solution is injected into the 3-channel microfluidic cell for 1 h. The brighter TSPR image is obtained after the injection of creatinine on the AgNPs/gold grating system. UV–vis absorption spectroscopy is used to study a 5-bilayer AgNPs/PDADMAC film on 10 layers of PDADMAC/PSS intermediate layers on BK7 glass slides before and after injection of creatinine. The AgNPs/PDADMAC film with a peak wavelength of 420 nm is deposited onto the surface of a PDADMAC/PSS multilayer. The plasmon absorption band of AgNPs at 420 nm reduced after injection of 10 mM creatinine. The creatinine sensor has a high sensitivity for creatinine measurement and a linear calibration range of 0.1 to 20 mM. On the TSPR-i system, a facile and cost-effective approach for label-free, real-time, and high-sensitivity has been established, which might be helpful for clinical applications. In this chapter 4, we constructed new approach for creatinine assay on polypyrrole (PPy) film utilizing SPR method. The change of SPR reflectivity induced by adsorption of the product of AgNPs and creatinine on polymer film. The creatinine at different concentrations is mixed with 20 ppm of AgNPs solution before injection of the product solution in a SPR sensor. The SPR reflectivity change on the substrate by the mixed solution with AgNPs is increased with increasing creatinine concentration whilst without AgNPs, no change is observed. Furthermore, the interaction between polymer film and product will be studied. The adsorption of AgNPs on the PPy film with creatinine increased the shift in SPR reflectivity. The SPR reflectivity increased with increasing creatinine content after adding the mixed solution to the PPy/gold substrate. The performance of the creatinine sensor is compared to that of three SPR sensor platforms: PPy film, PPy film with AgNPs, and PPy film by aggregated AgNPs. When compared to a substrate without aggregated AgNPs, the SPR sensor with aggregated AgNPs enhanced to about 4 folds, and the LOD is 0.19 µM. The developed technique has the potential to be beneficial in biomedical applications., 新大院博(工)第522号}, school = {新潟大学, Niigata University}, title = {Development of electrochemical-surface plasmon resonance biosensors using conducting polymers}, year = {} }