Au-TiO2 Coated Photonic Crystal Fiber Based SPR Refractometric Sensor for Detection of Cancerous Cells

A surface plasmon resonance (SPR) refractometric sensor based on gold (Au) and titanium dioxide (TiO₂) coated Photonic Crystal Fiber (PCF) is presented for the quick detection of various types of cancerous cells. The cancerous cells and their corresponding normal cells are both considered to be liquid cells each with their unique refractive index (RI). Normally these cells are found in liquid form in the suitable media (food) required to live the cancerous/normal cell lines. Also in our detection case, liquid samples are easy to pump into the sensing channel of the proposed PCF by employing either pressure or capillary forces.The proposed PCF sensor works on the SPR principle, with the Au coating serving as the plasmonic material. This sensor is investigated using the COMSOL Multiphysics software computational tool that is based on the full-vector finite element method (FEM). A TiO₂ coating has been applied to enhance adhesion between the Au layer and the PCF surface. Above the Au coating, cancerous cells samples are filled into the PCF. When the core mode of the PCF is coupled with the surface plasmon polariton (SPP) mode under the specific resonance circumstances, SPR will occur on the interface of the gold-sample cell, and in the core mode, the loss peak is observed at the resonance wavelength. Cancerous cells samples have a distinct loss peak than normal cells samples therefore the cancerous cells can be diagnosed by measuring the shift in resonance wavelength corresponding to the loss peak of cancerous and their normal cells samples. The proposed sensor may identify various cancerous cells such as MDAMB-231, MCF-7, PC12, HeLa, and Jurkat for the diagnosis of breast cancer type-1, breast cancer type-2, adrenal glands, cervical, and blood cancer respectively. The computed wavelengths sensitivities of the proposed PCF are 9428.57nm/RIU, 10714.28nm/RIU, 7571.43nm/RIU, 5500nm/RIU, and 6000nm/RIU for the MDAMB-231, MCF-7, PC12, HeLa, and Jurkat cancerous cells, respectively. However, for various cancerous cells, the maximum amplitude sensitivity varies from -1387 RIU^-1 to -1599 RIU^-1. Moreover, the sensor resolution ranges between 0.93 ×10^-5 RIU and 1.82 ×10^-5 RIU with a 0.024 maximum detection limit. Because of its improved sensing capability, the presented SPR refractometric sensor is appropriate for the early detection of cancerous cells.