Tomasz Gabler
supervisor: Mateusz Ĺmietana
The presentation shows miniaturized sensing solution based on a microcavity in a side surface of a single mode optical fiber (125 μm in cladding diameter) for label-free virus detection. The microcavity is fabricated using a femtosecond laser micromachining, and when forming an in-line Mach-Zehnder interferometer (μIMZI), it shows exceptional high refractive index sensitivity (>14,000 nm/RIU). Moreover, when antibodies were covalently immobilized at the μIMZI’s surface, the structure may work as an immunoassay to detect conserved regions of the SARS-CoV-2 viral particles, while the volumes of the investigated sample may be as small as hundreds of picoliters. In this work, custom-made biological components were used. Synthesized SARS-CoV-2 virus-like particles (VLPs) and nucleocapsid protein alone were detected at 3 ng/mL and 1 ng/mL concentration, respectively. The optical response was measured in a real-time and the result were obtainable in less than 30 minutes. The sensor shows no cross-reactivity with other respiratory tract viruses, thanks to the manufactured antibodies that show strong and highly specific affinity to RNA binding domain of nucleocapsid protein of SARS-CoV-2. The sensor offers a time-effective and highly sensitive alternative to other affinity-based SARS-CoV-2 detection approaches. Except for detection itself, the μIMZI could also analyze and validate the interaction between the low concentration/low-volume receptors and chosen targets.