Functionalised liquid crystal microfibers for hydrogen peroxide and catalase detection using whispering gallery mode

In this work, we demonstrate, for the first time, a whispering gallery mode (WGM) lasing-based liquid crystal (LC) soft-matter microfiber biosensor for real-time and sensitive detection of hydrogen peroxide and catalase. The functionalised nematic LC 4-cyano-4ʹ-pentylbiphenyl (5CB) microfibers served as both optical microresonators and sensing actuators. The resonance spectral shift in WGMs can be used as a stable and reliable indicator of analyte concentrations. The detection limits for hydrogen peroxide and catalase were as low as ~0.26 μM and ~1 ng/mL, respectively. Direct measurement of the WGM lasing spectrum of LC soft-matter microfibers can be expected as an alternative method to detect analytes without the need for polarised image analysis in current LC sensor systems. This research provides a preliminary basis for the development of soft-matter microfiber biosensors with high sensitivity for detecting biochemical molecules.