External Cavity Laser Biosensor for Label-Free and Enhanced Fluorescence Detection

1132225Cunningham the PI提出了一种新型的光学生物传感器的开发，该传感器利用光子晶体(PC)表面作为二极管泵浦的外腔激光器的一端面，能够同时进行高分辨率的无标记检测和荧光增强。PC是通过纳米复制件模塑在大表面积上使用塑料材料廉价制造的，用于集成到多孔微板中，并被设计为用作共振反射滤光片。对于无标记生物传感，生物材料在PC表面的吸附导致其谐振波长的移动，从而产生外腔激光工作波长的调谐。为了增强荧光，PC表面在激光发射波长下的光学驻波将被设计为与用作生物分子标签的荧光染料分子的光学吸收波长一致，从而与普通玻璃表面相比产生放大的荧光团激发。外腔结构提供单模、连续波、可广泛调谐的窄带激光输出，其中受激发射过程利用半导体二极管提供的增益产生有源光学生物传感器，与前几代各种无源反射器/发射器形成对比。本提案中描述的方法代表了高灵敏度+高分辨率无标记检测的前所未有的组合。该项目将在最近初步演示外腔激光生物传感器的基础上，实现PC传感器表面和检测仪器的多模式操作，以实现高精度参考、亚PM波长调谐，并降低无标记和荧光标记生物分子分析的检测限制。

1132225Cunningham The PI proposes a development of a new type of optical biosensor that utilizes a photonic crystal (PC) surface as one end facet of a diode-pumped external cavity laser that is capable of both high resolution label-free detection and fluorescence enhancement. The PC is fabricated inexpensively using plastic materials over large surface areas by nanoreplica molding for incorporation into multiwell microplates, and is designed to operate as a resonant reflection filter. For label-free biosensing, adsorption of biomaterial onto the PC surface results in a shift in its resonant wavelength, producing tuning of the external cavity laser operating wavelength. For enhanced fluorescence, rapid buildup of optical standing waves upon the PC surface at the laser emission wavelength will be designed to coincide with the optical absorption wavelength of fluorescent dye molecules used as biomolecule tags, resulting in amplified fluorophore excitation compared to an ordinary glass surface. The external cavity configuration provides single mode, continuous wave, widely tunable, narrowband laser output in which the stimulated emission process, with gain provided by a semiconductor diode, generates an active optical biosensor, in contrast to the wide variety of previous generations of passive reflectors/transmitters. The approach described in this proposal represents an unprecedented combination of high sensitivity + high resolution label-free detection. The project will expand upon recent preliminary demonstration of the external cavity laser biosensor to implement PC sensor surfaces and detection instrumentation capable of multi-mode operation for highly accurate referencing, sub-pm wavelength tuning, and reduction in detection limits for both label-free and fluorescence-tagged biomolecular assays.