| Summary: | 碩士 === 國立中正大學 === 化學所 === 98 === The objective of this work is to develop novel chemical and biochemical sensing platforms with characteristics of label-free, high-sensitivity, high-throughput, low-cost, portable size and easy operation. The tubular waveguide-based localized plasmon resonance (LPR) chemical and biochemical sensing platform exactly fits this objective. The principle of this invention is using an optical waveguide technology to produce multiple total internal reflections (TIR) along the tubular waveguide wherein at the reflection interface the evanescent wave excites the LPR of the noble metal nanoparticles.
When a noble metal nanoparticle is affected by the change of the refractive index of its surrounding environment, its plasmon resonance condition will change. This phenomenon can be used as the basis of chemical and biological sensing. Hence, when the surface of the noble metal nanoparticles is modified with a recognition molecule, selective chemical and biochemical can be achieved since the molecular interaction cause a change of the local refractive index around the noble metal nanoparticles. Due to multiple TIR, the LPR signal is significant enhanced and thus enhancing the sensitivity of our sensing platform. This arrangement simplifies the biosensor design and facilitates the development of a portable biosensor, in which the glass tube not only is a sample container but also acts as a waveguide. The integration of the tubeular waveguide sensor with photoelectronics results in a miniaturized, low-cost, high-sensitivity and high-throughput chemical and biological sensing platform. Results show that a refractive index resolution of 10-5 RIU and limit of detection (LOD) of 0.5 pM and 3 pM for ant-DNP and streptavidin, respectively, can be reached.
Although direct detection of small molecules is less sensitive by this approach, due to the smaller change in local refractive index, the application of competitive method may improve the sensitivity. Using biotin conjugated gold nanoparticles as the labeled analyte, the LOD for biotin is about 100 times improved than that by the direct detection method.
To increase the throughput of the biosensing platform, we haven taken efforts to develop multi-channel platform. So far, we have set up a two-channel platform for testing. The refractive index resolution for this two-channel platform can reach about 10-5 RIU and the ability to detect biochemical molecules has been verified.
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