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

申请人建议研究基于逐渐耦合到光纤的介电微球的光子传感器，并开发用于生化和生物传感的微球传感器。这种微球中空前窄的光学共振为一类新型的全光传感器开辟了一条道路，这种传感器可以通过检测共振的光学频移来测量局部性质。在一个极窄的线宽内，微球中出现了许多光子共振模。共振光谱是通过扫描穿过光纤进入微球的激光的波长，并通过耦合到微球的读出光纤观察强度来获得的。共振波长漂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为敏感。后一个量由温度、第二种物质在球体表面的吸附、各向同性和各向异性应力以及围绕球体的溶液中化学物质的浓度决定。努力将特别针对开发用于生物流体的显微传感头。为此，将使用纤维和微球，这些纤维和微球都是由可以实现生物相容性的聚合物制成的。生物分子相互作用的高度特异性将使特定的RNA、蛋白质、酶、底物和抗原的检测成为可能。其目标是使人们能够制备与生物分子数量一样多的传感器。微型、高灵敏度生物光子学传感器的问世将促进组合化学中芯片设备和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.