This paper provides a simple hybrid design and numerical analysis of the graphene-coated fiber-optic surface plasmon resonance (SPR) biosensor for breast cancer gene-1 early onset (BRCA1) and breast cancer gene-2 early onset (BRCA2) genetic breast cancer detection. Two specific mutations named 916delTT and 6174delT in the BRCA1 and BRCA2 are selected for numerical detection of breast cancer. This sensor is based on the technique of the attenuated total reflection (ATR) method to detect deoxyribonucleic acid (DNA) hybridization along with individual point mutations in BRCA1 and BRCA2 genes. We have numerically shown that momentous changes present in the SPR angle (minimum: 135 % more) and surface resonance frequency (SRF) (minimum: 136 % more) for probe DNA with various concentrations of target DNA corresponding to a mutation of the BRCA1 and BRCA2 genes. The variation of the SPR angle and SRF for mismatched DNA strands is quite negligible, whereas that for complementary DNA strands is considerable, which is essential for proper detection of genetic biomarkers (916delTT and 6174delT) for early breast cancer. At last, the effect of electric field distribution in inserting graphene layer is analyzed incorporating the finite difference time domain (FDTD) technique by using Lumerical FDTD solution commercial software. To the best of our knowledge, this is the first demonstration of such a highly efficient biosensor for detecting BRCA1 and BRCA2 breast cancer. Therefore, the proposed biosensor opens a new window toward the detection of breast cancers.

This article illustrates a design and finite difference time domain (FDTD) method based on analysis of fiber optic surface plasmon resonance (SPR) biosensor for biomedical application especially for DNA-DNA hybridization. The fiber cladding at the middle portion is constructed with the proposed hybrid of gold (Au), graphene, and a sensing medium. This sensor can be recognized adsorption of DNA biomolecules onto sensing medium of PBS saline using attenuated total reflection (ATR) technique. The refractive index (RI) is varied owing to the adsorption of different concentration of biomolecules.  Result states that the sensitivity with a monolayer of graphene will be improved up to 40% than bare graphene layer. Owing to increased adsorption capability of DNA molecules on graphene, sensitivity increases compared to the conventional gold thin film SPR biosensor. Numerical analysis shows that the variation of the SPR angle for mismatched DNA strands is quite negligible, whereas that for complementary DNA strands is considerable, which is essential for proper detection of DNA hybridization.  Finally, the effect of Electric field distribution on inserting graphene layer is analyzed incorporating the FDTD technique by using Lumerical FDTD solution software.

In this paper, we compare the sensitivity of graphene-MoS2 based surface plasmon resonance (SPR) biosensor to graphene based SPR biosensor. Here, graphene is used as biomolecular recognition element (BRE) because of its high adsorption ability and optical characteristics which helps to improve sensor sensitivity, on the other hand MoS2 is used for it has larger band gap, high fluroscence quenching ability, higher optical absorption efficiency which improves further sensor sensitivity. In DNA hybridization event, numerically achieved results show that single layer of graphene-MoS2 based SPR biosensor is 175% more sensitive than single layer of graphene coated SPR biosensor. Surface plasmon resonance angle and spectrum of reflected power are numerically investigated for different concentrated complementary DNA strands. The variations of SPR angle is significantly computable for complementary DNA strands whereas these parameters are varied negligibly for mismatched DNA strands. Thus the proposed sensor effectively differentiates hybridization and single nucleotide polymorphisms (SNP) by examining the level of changes in SPR angle and reflected power spectrum.

In this paper, an extremely birefringent PCF based on a modified decagonal (MD-PCF) arrangement is studied for broadband compensation covering the S-, C- and L-communication bands wavelength ranging from 1460 to 1625 nm. It is made known in theory that it is conceivable to attain negative dispersion coefficient about − 448 to − 835 ps/nm/km covering S-, C- and L-communication bands as well as a relative dispersion slope near to single mode fiber (SMF) of 0.0036 nm−1. On the basis of simulation results incorporating finite-element method based COMSOL multiphysics software, birefringence is obtained as high as 1.7 × 10−2, which is definately greater than conventional step-index fiber (SIF) and circular air- holes PCF so far. We also discuss the characteristics of chromatic dispersion, effective area and confinement loss of the designed PCF.