Optical biosensors using plasmonic and photonic crystal band-gap structures for the detection of basal cell cancer

Abstract

One of the most interesting topics in bio-optics is measuring the refractive index of tissues. Accordingly, two novel optical biosensor configurations for cancer cell detections have been proposed in this paper. These structures are composed of one-dimensional photonic crystal (PC) lattices coupled to two metal–insulator–metal (MIM) plasmonic waveguides. Also, the tapering method is used to improve the matching between the MIM plasmonic waveguides and PC structure in the second proposed topology. The PC lattices at the central part of the structures generate photonic bandgaps (PBGs) with sharp edges in the transmission spectra of the biosensors. These sharp edges are suitable candidates for sensing applications. On the other hand, the long distance between two PBG edges causes that when the low PBG edge is used for sensing mechanism, it does not have an overlapping with the high PBG edge by changing the refractive index of the analyte. Therefore, the proposed biosensors can be used for a wide wavelength range. The maximum obtained sensitivities and FOM values of the designed biosensors are equal to 718.6, 714.3 nm/RIU, and 156.217, 60.1 RIU−1, respectively. The metal and insulator materials which are used in the designed structures are silver, air, and GaAs, respectively. The finite-difference time-domain (FDTD) method is used for the numerical investigation of the proposed structures. Furthermore, the initial structure of the proposed biosensors is analyzed using the transmission line method to verify the FDTD simulations. The attractive and simple topologies of the proposed biosensors and their high sensitivities make them suitable candidates for biosensing applications.

Ultrasensitive and label-free, graphene/CaF2 multilayer-based biosensor for detecting gasses, cancers, viruses, and diabetes, with significant improvement of sensitivity, quality factor, and figure of merit

“…The refractive index of Adrenal Gland Cancer is 1.395 with an 80% concentration, and its normal cell owns a RI of 1.381 in the 30-70% concentration [58]. Also, Breast cancer I and type II own the normal cells with the RI of 1.385 and 1.387 [59]. Finally, the RI of skin cancer (Basal Cell) with an 80% concentration is 1.38, and its normal cell (basal cell) RI with a concentration in the range of (30-70%) is 1.36 [58-60].…”

Shining a Light on Cancer—Photonics in Microfluidic Tumor Modeling and Biosensing

“…[ 152 ] Last, their refractive index is a simple yet powerful characteristic of cells that can be leveraged for optical cancer cell detection. [ 153 ] Different types of cells and cellular components present varying types of refractive indices. This characteristic can also be leveraged for the previously referred holographic imaging to determine cell shape and alterations in the cytoskeleton.…”

A selectivity‐enhanced colloidal crystal array for ribavirin sensing based on the synergistic effect of covalent and non‐covalent interactions

“…Due to the ordered periodic structure of CCAs, iridescent structural colors emerge from Bragg reflection and constructive interference 10–13 . The iridescent structural colors make them promising for various applications, such as anti‐counterfeiting labels, 14−16 biosensors 17,18 and color displays and printing 19−22 . If the CCAs are integrated with hydrogel polymers, the structural colors are tunable upon hydrogel swelling or shrinking.…”