Biophotonics: Biophotonic Sensors Based on Polymer Microspheres Evanescently Coupled to Optical Fiber

申请人提出研究基于渐逝耦合到光纤的介电微球的光子传感器，并开发用于生物化学和生物感测的微球传感器。这种微球中前所未有的窄光共振为一类新型的全光传感器开辟了一条途径，该传感器可以通过检测共振的光频移来测量局部特性。许多光子共振模式发生在一个非常窄的线宽微球。通过扫描通过光纤传输到微球中的激光的波长并通过耦合到微球的读出光纤观察强度来获得共振光谱。共振波长偏移对球体的直径和折射率以及球体周围介质的折射率的变化极其敏感。后者的量由温度、第二物质在球体表面上的吸附、各向同性和各向异性应力以及球体周围溶液中化学物质的浓度确定。 努力将特别针对开发用于生物流体的显微传感头。为此目的，将使用纤维和微球，它们都是由可赋予生物相容性的聚合物制成的。生物分子相互作用的高特异性将使得能够检测特定的RNA、蛋白质、酶、底物和抗原。目标是允许人们制备与生物分子数量一样多的传感器。微型，高灵敏度的生物光子传感器的可用性将促进“芯片上的设备”和组合化学中的其他并行化学和生物分析系统的发展。

0119273ArnoldThe applicant proposes to investigate photonic sensors based on dielectric microspheres evanescently coupled to optical fibers, and to develop microsphere sensors for biochemical and biological sensing. The unprecedentedly narrow optical resonances in such microspheres open an avenue for a novel class of all-optical sensors which can measure local properties by detecting optical frequency shifts of the resonances. Many photonic resonance modes occur in a microsphere in an extremely narrow linewidth. The resonance spectrum is obtained by scanning the wavelength of the laser transmitted through the fiber into the microsphere and observing the intensity through a read-out fiber coupled to the microsphere. Resonance wavelength shifts are extremely sensitive to changes in the diameter and the refractive index of the sphere as well as the refractive index of the medium surrounding the sphere. The latter quantities are determined by the temperature, adsorption of a second substance onto the sphere surface, the isotropic and anisotropic stress, and the concentration of a chemical in the solution surrounding the sphere. Efforts will be especially targeted at developing microscopic sensing heads for biofluids. For this purpose fibers and microspheres, all made of polymers that can be rendered biocompatible will be used. The high specificity in biomolecular interactions will enable detection of a specific RNA, protein, enzyme, substrate, and antigen. The goal is to allow one to prepare as many kinds of sensors as the number of biomolecules. Availability of miniature, high-sensitivity biophotonic sensors will facilitate the development of 'device on a chip' and other parallel chemical and biological analysis systems in combinatorial chemistry.