Leibniz Institute of Photonic Technology, Albert-Einstein-Str. 9, 07745 Jena, Germany.
Abbe Center of Photonics and Faculty of Physics, Friedrich-Schiller-University Jena, 07743 Jena, Germany.
Anal Chem. 2021 Jan 19;93(2):752-760. doi: 10.1021/acs.analchem.0c02857. Epub 2020 Dec 9.
Emerging applications in spectroscopy-related bioanalytics demand for integrated devices with small geometric footprints and fast response times. While hollow core waveguides principally provide such conditions, currently used approaches include limitations such as long diffusion times, limited light-matter interaction, substantial implementation efforts, and difficult waveguide interfacing. Here, we introduce the concept of the optofluidic light cage that allows for fast and reliable integrated spectroscopy using a novel on-chip hollow core waveguide platform. The structure, implemented by 3D nanoprinting, consists of millimeter-long high-aspect-ratio strands surrounding a hollow core and includes the unique feature of open space between the strands, allowing analytes to sidewise enter the core region. Reliable, robust, and long-term stable light transmission via antiresonance guidance was observed while the light cages were immersed in an aqueous environment. The performance of the light cage related to absorption spectroscopy, refractive index sensitivity, and dye diffusion was experimentally determined, matching simulations and thus demonstrating the relevance of this approach with respect to chemistry and bioanalytics. The presented work features the optofluidic light cage as a novel on-chip sensing platform with unique properties, opening new avenues for highly integrated sensing devices with real-time responses. Application of this concept is not only limited to absorption spectroscopy but also includes Raman, photoluminescence, or fluorescence spectroscopy. Furthermore, more sophisticated applications are also conceivable in, e.g., nanoparticle tracking analysis or ultrafast nonlinear frequency conversion.
新兴的光谱相关生物分析应用需要具有小几何足迹和快速响应时间的集成设备。虽然空心光纤波导主要提供了这些条件，但目前使用的方法包括扩散时间长、光物质相互作用有限、实施工作量大以及波导接口困难等限制。在这里，我们介绍了光流体光笼的概念，该概念允许使用新型片上空心光纤波导平台进行快速可靠的集成光谱学。该结构通过 3D 纳米印刷实现，由环绕空心芯的毫米长高纵横比股线组成，并具有股线之间有空隙的独特特征，允许分析物侧向进入芯区。当光笼浸入水相环境时，观察到通过抗共振导光的可靠、稳健和长期稳定的光传输。光笼与吸收光谱、折射率灵敏度和染料扩散相关的性能通过实验确定，与模拟匹配，从而证明了这种方法在化学和生物分析方面的相关性。所提出的工作以独特的特性将光流体光笼作为新型片上传感平台，为具有实时响应的高度集成传感设备开辟了新途径。该概念的应用不仅限于吸收光谱学，还包括拉曼、光致发光或荧光光谱学。此外，在例如纳米颗粒跟踪分析或超快非线性频率转换等方面，还可以设想更复杂的应用。
