Novel Bottom-Side Polished PCF-Based Plasmonic Biosensor for Early Detection of Hazardous Cancerous Cells

This work presents a single-core bowl-shaped bottom-side polished (BSP) photonic crystal fiber (PCF) sensor based on surface plasmon resonance (SPR) concept for the early detection of hazardous cancer cells in human blood, skin, cervical, breast, and adrenal glands. We have studied liquid samples of cancer-affected and healthy samples with their concentrations/refractive indices in the sensing medium. To induce a plasmonic effect in the PCF sensor, the bottom flat section of a silica PCF fiber is coated with a 40nm plasmonic material, such as gold. To strengthen this effect, a thin TiO₂ layer of 5 nm is sandwiched between fiber and gold as it strongly holds gold nanoparticles with smooth fiber surface. When the cancer-affected sample is introduced to the sensor's sensing medium, it produces a different absorption peak in the form of a resonance wavelength than the healthy sample. This reallocation of the absorption peak is used to determine sensitivity. Hence, the obtained sensitivities for blood cancer, cervical cancer, adrenal gland cancer, skin cancer, and breast cancer (type-1and type-2) cells are 22,857nm/RIU, 20000nm/RIU, 20714nm/RIU, 20000nm/RIU, 21428nm/RIU, and 25000nm/RIU, respectively, with highest detection limit 0.024. These strong findings indicate that our proposed cancer sensor PCF is a viable choice for early cancer cell detection.