Graphene-Coated Optical Fiber SPR Biosensor for BRCA1 and BRCA2 Breast Cancer Biomarker Detection:a Numerical Design-Based Analysis

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.

A Numerical Approach to Design the Kretschmann Configuration Based Refractive Index Graphene-MoS_(2) Hybrid Layers With TiO_(2)-SiO_(2) Nano for Formalin Detection

In this paper,a Kretschmann configuration based surface plasmon resonance(SPR)sensor is numerically designed using graphene-MoS_(2) hybrid structure TiO_(2)-SiO_(2) nano particles for formalin detection.In this design,the observations of SPR angle versus minimum reflectance and SPR frequency(FSPR)versus maximum transmittance(Tmax)are considered.The chitosan is used as probe legend to perform reaction with the formalin(40%formaldehyde)which acts as target legend.In this paper,both graphene and MoS_(2) are used as biomolecular acknowledgment element(BAE)and TiO_(2) as well as SiO_(2) bilayers is used to improve the sensitivity of the sensor.The numerical results show that the variation of FSPR and SPR angles for inappropriate sensing of formalin is quite insignificant which confirms the absence of formalin.On the other hand,these variations for appropriate sensing are considerably significant that confirm the presence of formalin.At the end of this article,the variation of sensitivity of the proposed biosensor is measured in corresponding to the increment of a refractive index with a refractive index step 0.01 refractive index unit(RIU).In inclusion of TiO_(2)-SiO_(2) bilayers with graphene-MoS_(2),a maximum sensitivity of 85.375%is numerically calculated.