利用二氧化矽及金奈米顆粒混合組成層的病毒體光學檢測

Abstract

由貴重金屬奈米顆粒特有之區域性表面電漿共振現象所引起的吸收光譜，對於比鄰環境的折射率變化十分敏銳，故已被應用在光學生物感測的領域上。 在本研究中，我們設計一種二氧化矽暨金奈米顆粒混合組成層，利用共價及化學鍵結，將二氧化矽奈米球、金奈米顆粒、玻璃基材組裝在一起。 在此元件的吸收光譜中，我們觀察到「雙波峰」的現象,並將之用在生物分子的感測上。 利用此元件測試不同濃度葡萄糖溶液可以模擬元件對於環境之折射率改變的檢測的狀況。目前可檢測到的最小溶液折射率變化，受限於折射率計的最低有效位數為 。 做為檢測抗原-抗體反應的生物感測器，我們利用已固定在元件表面的禽類流感病毒(表面帶有血球凝集素第五型的亞型)可以檢測到濃度為10 μg/ml 之針對血球凝集素第五型的抗體。 此種抗原-抗體專一性鍵結造成的吸收光譜劇烈變化在非專一性鍵結的實驗中是沒有量測到的。 此種利用區域性表面電漿共振原理的奈米顆粒層可以在任何透光的二氧化矽表面組成。 搭配高靈敏度的光感系統，此二氧化矽暨金奈米顆粒混合組成層有潛力成為超高靈敏度的可微小化生物感測工具。

The LSPR-induced absorption spectrum of noble metal nanoparticles are known for optical biosensing via its sensitivity toward environmental refraction index variation. To perform nanoparticles on substrate, we designed a heterogeneous assembly SiO2/Au nanoparticle layer using the covalent and chemical attachment between substrate, silica nanospheres, and gold nanoparticles. A “double-peak” absorption spectrum is observed while measuring the spectrum of this device, and is used as a tool for biomolecular sensing. Glucose solutions of different concentrations were tested by the chip to simulate the detecting of refraction index change. The minimum refraction index change of solutions being detected is below but bounded by the detection limit of the refractometer ( ). As a biosensor for antigen-antibody reaction, 10 μg/ml anti-H5 can be detected by binding with the avian influenza virus (AIV H5) immobilized on our chip, This specific binding causes intense variation in the absorption spectrum, while nonspecific antibodies induced extremely weak variations. This LSPR based nanoparticles layer sensor can be assembled on any transparent silica substrates. With a photodetecting system with high resolution, the heterogeneous assembly SiO2/Au nanoparticle layer has the potential to provide an ultrahigh sensitive and minimizable biosensing tool.