Plasmonic Biosensiing in Microfluidic Devices. Binding Kinetics Measurement and Surface Enhanced Fluorescence and Surface Enhanced Raman Signal Detection
| Autor: | Ting-Chou Chang, 張廷州 |
|---|---|
| Rok vydání: | 2015 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 103 One simple and label-free biosensing method has been developed for determining the binding kinetic constants of anti-ovalbumin antibody (anti-OVA antibody) and anti-mouse IgG antibody using the fiber optic particle plasmon resonance (FO-PPR) biosensor. The FO-PPR sensor is based on gold nanoparticle-coated optical fiber where the gold nanoparticle surface has been modified by a mixed self-assembled monolayer for conjugation of a molecular probe reporter (ovalbumin or mouse IgG) to dock with the corresponding analyte species such as anti-OVA antibody or anti-mouse IgG. The binding process occurrence of an event when an analyte reacts with a probe molecule immobilized on the optical fiber can be monitored in real-time. In addition, by assuming a Langmuir type of adsorption isotherm to measure the initial binding rate, the quantitative determination of binding kinetic constants, association and dissociation rate constants, yields ka of (7.2 ± 0.4) × 103 (M-1s-1) and kd of (2.97 ± 0.6) × 10-3 (s-1), respectively for OVA/anti-OVA antibody, and ka of (1.45 ± 0.2) × 106 (M-1s-1) and kd of (2.97 ± 0.6) × 10-2 (s-1), respectively for mouse IgG/anti-mouse IgG. We successfully demonstrate that the FO-PPR biosensor can study real-time biomolecular interactions. In addition, because of accurate, fast and low-cost quantification of a large number of biomarkers can enable frequent home screening for early diagnosis of chronic diseases and cancers; I report a new nanocone array technology that can lead to the desired home-use screening devices. Switchable fluorescence hairpin oligo probes are functionalized onto Au nanoparticles for highly specific label-free nucleic acid sensing. To enhance the fluorescence signal, the nanoparticles are coated on the 10-nm tips of a nanocone array, made by wet-etching a 1-mm diameter optical imaging fiber bundle of 6-mircon fibers. The excitation light is focused by converging tip particle plasmonic resonance (PPR) and singular scattering off the singular nanocones. The enhanced fluorescent signal allows detection by inexpensive optical detectors. We report the limit of detection of sensor is down to fM and five orders dynamic range. As the fluorophore quenching effect by the metal nanoparticles decays faster, we use surface enhanced Raman scattering to prevent the drawback in fluorescence detection. SERS is also shown to benefit from the singular scattering and tip plasmonic effects of gold-coated conical tips. They enhance nanoparticle SERS Raman scattering signals of Rhodamine-6G and TRITC dyes by seven to eight orders of magnitude enhancement. At final, the technique of using femtosecond laser to fabricate the three-dimensional interior microstructures in one closed flow channel of plastic substrate is investigated to manufacture the micro-mixer. This microchip is able to decrease the reaction time. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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