Abstract
The platform presented here was devised to address the unmet need for real time label-free in vivo sensing by bringing together a refractive index transduction mechanism based on Whispering Gallery Modes (WGM) in dye doped microspheres and Microstructured Optical Fibers. In addition to providing remote excitation and collection of the WGM signal, the fiber provides significant practical advantages such as an easy manipulation of the microresonator and the use of this sensor in a dip sensing architecture, alleviating the need for a complex microfluidic interface. Here, we present the first demonstration of the use of this approach for biological sensing and evaluate its limitation in a sensing configuration deprived of liquid flow which is most likely to occur in an in vivo setting. We also demonstrate the ability of this sensing platform to be operated above its lasing threshold, enabling enhanced device performance.
Highlights
To determine the lasing threshold of the processed dye doped polystyrene microspheres, the excitation power was systematically varied from 5 μW to 100 μW and the corresponding Whispering Gallery Modes (WGM)
We have demonstrated the ability of a single dye-doped polymer microsphere to be turned into a microlaser at the tip of a suspended core optical fiber which in turns enables enhanced sensor resolution in individual measurements and can to be used to detect a specific analyte, neutravidin in this case, down to a concentration of 4 nM (0.20 μg/mL) in an experimental setting deprived of liquid flow, mimicking the conditions anticipated for in vivo sensing applications
This result raises the question of the suitability of such sensing platform for the detection of proteins using an antibody/antigen assay, especially when the molecule to be detected is in small concentration
Summary
Over the last decade, whispering gallery modes (WGMs) have found applications in label-free optical biosensing, enabling operation down to the single molecule level [1,2] and miniature laser. Our approach is to combine WGMs as transduction mechanism using an active spherical resonator integrated onto the tip a suspended core Microstructured Optical Fiber (MOF) to create a label-free biosensing platform with the potential application for in vivo biosensing. In-vivo biological sensing is an emerging field with much promise for revolutionary medical diagnostic applications and fundamental breakthrough in biology by enabling measurements to be performed where it has not been possible so far [23] In this context, optical fiber probes are suited for minimally invasive procedure where the tip of the fiber is rendered active toward the detection of a specific biochemical compound [24,25].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
