Refractive Index Biosensor Research Articles

Performance Evaluation of Refractive Index Biosensor in THz Regime for Clinical Applications: A Simulation Approach

In this manuscript, a novel innovative HC-PCF sensor model in THz regime is introduced integrated with an optimization approach. The suggested sensor architecture provides crucial advantages precise identification of healthy and ill tissues in healthcare industry. The HC-PCF, meticulously constructed with specific dimensions, significantly increases the sensor sensitivity and specificity to 99.37% and 99.75% respectively. Healthcare industries are at the core of investigations and are undoubtedly crucial to modernize the prognosis procedures. It is a discipline that is continually expanding and searching for new approaches to raise the standard for efficacy, sensitivity, and accuracy. Recently, THz PCF has emerged with incredible potential in all the areas of biomedical applications. The importance in using THz sensors in this research is to detect the ill tissues, an important component in the categorizing diabetes. The integrated sensor architecture provides higher level of sensitivity, with a confinement loss of 0.05 in 0.23 s processing time for a RI range of 1.28–1.39. This research highlights the capability of combining PCF with optimization to improvise the healthcare industry, offering an economical and efficient diagnostic solution across the fields.

Design and optimization of refractive index biosensor for MDA-MB-231 and MCF-7 breast cancer biomarker detection

Breast cancer is the leading malignancy in women and the 2nd widespread cancer globally. Earlier identification of breast cancer can improve treatment outcomes and prevent metastasis beyond the breast. Traditional screening tests are not sensitive enough for early diagnosis and have extended detection periods. Recent studies have explored diversified Breast cancer biosensor techniques, including optical, electrical, electrochemical, and mechanical biosensors. This paper nominates a circlet with a large plus sign refraction indices biosensor for the evaluation of two distinct breast cancer cells namely, MDA-MB-231 and MCF-7. The supreme sensitivity has been viewed as 1714.28 nm/RIU for the MDA-MB-231 and 1714.28 nm/RIU for the MCF-7. The supreme quality factor (QF) value for UC1(usual cell of MDA-MB-231) is 10.52, for CC1(cancer cell of MDA-MB-231) is 11.94, for UC2 (usual cell of MCF-7) is 10.64, and for CC2 (cancer cell of MCF-7) is 12.09. The minimal detection value (DL) for UC1 is 0.1573, CC1 is 0.1360, UC2 is 0.1554, and CC2 is 0.1341. This nominated sensor has the potential to sense breast tumor biomarkers.

Plasmonic and photonic refractive index biosensor based on bound states in the continuum

In this paper, we propose a novel structure for biosensors based on a diffraction grating to diagnose four types of cancers cells. This biosensor is used to detect Hela, Jurkat, PC12, MDA-MB-231 and MCF-7 cancerous cells, based on their refractive indices. The present configuration consists of a glass layer covered by a gold layer, a grating coated by a silicon nitride layer separating the sensor from sensing medium. Bound states in the continuum (BIC) in a hybrid plasmonic-photonic structure can be achieved at Γ point and off-Γ. The symmetry-protected BIC is formed at the Γ-point of the periodic system due to the strong coupling between plasmonic or photonic modes. On the other hand, the Friedrich-Wintgen (FW) BICs can be readily achieved off-Γ due to the strong coupling between plasmonic and photonic modes. A comparative study is made on the basis of three BICs (plasmonic BIC, photonic BIC, and FW-BIC). Here, numerical analysis based on the Rigorous coupled-wave analysis method (RCWA) is performed to optimize the biosensor sensitivity, by also considering the full width at half maximum (FWHM), detection accuracy (DA), and figure of merit (FoM). The FW BIC-based biosensor for photonic mode exhibits the highest S of 1208nm/RIU, low FWHM of 0.5 nm, the maximum DA of 2 nm −1, and best FoM of 2416 RIU −1.

Design and analysis of efficient refractive index Biosensor for detection of Mycobacterium tuberculosis

Design and analysis of efficient refractive index Biosensor for detection of Mycobacterium tuberculosis

3D printed sub-terahertz photonic crystal for wireless passive biosensing

Monitoring pathogens has become a major challenge for society and research in recent years. Of great interest are refractive index sensors, which are based on the interaction between analytes and electromagnetic waves and allow label-free and fast detection. In addition, the electromagnetic waves can be exploited for wireless communication. However, current refractive index biosensors can only be read from a few centimeters. Here, we demonstrate an innovative concept of a passive wireless sensor based on a sub-terahertz photonic crystal resonator. The fabricated sensors have a reading range of up to 0.9 m and elevation and azimuth acceptance angles of around 90°. We demonstrate the stand-off detection of sub-µm thin-film proteins as test analytes. The proposed wireless sensor opens the door to a non-electronic, compact, and low-cost solution and can be extended to a wireless sensor network monitoring airborne pathogen, which may provide a pre-infection detection to prevent their spread efficiently.

Multiple Fano resonator based on photonic crystal waveguide coupled with two micro-cavities for biomedical sensing application

In order to acquire a miniature refractive index (RI) biosensor with high sensitivity, fast and selective for ultra-low concentrations of molecules, a new Photonic Crystal (PhC) biosensor based on a waveguide coupled to a Fano resonator is proposed for cancer cells detection. An optimized structure of the biosensor can detect cells cancers (Besal, Hela, Jurkat and PC12) in a biological solution deposited on the surface of the resonator. The detection mechanism uses the refractive index as a detection element. The performance of the proposed biosensor is studied by analyzing the variations in the transmission spectrum of different normal and cancer cells. The proposed structure is multimode PhC, with silica as a dielectric material. The finite element method (FEM) have been implemented for studying and investigating the numerical values. The simulation results display that the proposed biosensor attains spectral sensitivities of ‘513.12 nm RIU−1’, ‘587.28 nm RIU−1 ’, ‘702.35 nm RIU−1 ’ and ‘690.57 nm RIU−1 ’ corresponding to Hela cells, PC12 cells, Basal cells and Jurkat cells, respectively. And he qualilty factor Q of the Fano resonance mode can reach 3040.26. Our optimized design ensures easy fabrication with ongoing techniques. This study may open a new way for the development of integrated optical circuits and biosensing.

Optimization of Graphene-Based Square Slotted Surface Plasmon Resonance Refractive Index Biosensor for Accurate Detection of Pregnancy

Optimization of Graphene-Based Square Slotted Surface Plasmon Resonance Refractive Index Biosensor for Accurate Detection of Pregnancy

2D photonic crystal biosensing platform based on coupled defective ring-shaped microcavity-two waveguides for diabetes detection using human tears

This paper describes a two modes refractive index sensor based on photonic crystals (PhCs) for detecting diabetes in human tears samples. PhC-based biosensors are promising platforms to detect the analyte due to their high sensitivity and selectivity, low cost, and can be easily integrated with other electrical components. The proposed PhC biosensor consists of two waveguides coupled with one defective ring-shaped microcavity, the microcavity was created by removing seven lattice holes and shifting the inner ring-shaped hole vertically down by 0.45a, the whole microcavity system is separated from the two waveguides by three holes. The achieved sensitivity for this device comes out to be 659.83 nm RIU−1. The Q-factor, figure of merit (FOM), and limit of detection (LOD) were about 106, 106 RIU−1,and 10−7 RIU respectively. In general, our results revealed that the proposed device has appreciable potential to be used as a powerful tool to detect diabetes using tears. Furthermore, the proposed biosensor can be used as an alternative to painful pinpricks for diabetes testing. A brief comparison between the presented design and related literatures for detecting diabetes using refractive index biosensors is made to ensure effectiveness and the validity of the proposed biosensor. The high performance and simple design of the proposed biosensor make it a suitable candidate for bio-sensing applications.

SPR-Based refractive index sensor using BaTiO3 and WS2 with Al-Ni bimetal for glucose sensing

In this work, we propose a high-performance surface plasmon resonance (SPR)-based refractive index biosensor to determine the glucose concentration in the urine samples. To achieve the most efficient design for the sensor, four possible designs have been investigated. The proposed design of the sensor uses the Kretschmann configuration, which consists of a BK7 glass prism with Aluminum (Al) and Nickel (Ni) metallic layers separated by a dielectric layer of barium titanate (), and a 2D material tungsten disulfide () layer placed above the Ni layer. The dielectric layer of is used to enhance the shift in the resonance angle and to increase the absorption of the biomolecules, which results in an increase in the sensitivity of the sensor. The performance of the sensor has been numerically investigated using the transfer matrix method at wavelength. Minimum reflectance at resonance is studied to show the coupling strength of the incident light with the surface plasmons. The thicknesses of the Al and Ni metallic layers have been optimized for maximum sensitivity and minimum reflectance at the resonance. The performance of the proposed sensor has been investigated to obtain sensitivity for different glucose concentrations in the urine samples. The sensor has a sensitivity of for glucose concentration in the range The corresponding glucose concentration sensitivity is 0.4 The proposed study would be helpful in designing the refractive index-based biosensor for medical diagnostics applications.

Optimization of the Geometrical Design for an All-Dielectric Metasurface Sensor with a High Refractive-Index Response

This study aims to develop a refractive-index sensor operating in the visible region using an all-dielectric metasurface, which was chosen for its advantages of low optical loss and narrow spectral bandwidth, compared to those of conventional metallic metasurfaces. COMSOL software was utilized as a calculation tool to simulate the resonant properties of an all-dielectric metasurface composed of a circular nanohole-structured titanium oxide (TiO2) thin film, with the aim of enhancing the sensitivity of the refractive index for sensing targets. The simulation focused on finding the best geometrical conditions for the all-dielectric metasurface to achieve high sensitivity. Two resonance modes observed in this metasurface were considered: the quasi-bound-state-in-the-continuum (qBIC) mode and the perfect-reflection (PR) mode. The simulated results demonstrated that high sensitivities of 257 nm/RIU at the PR mode and 94 nm/RIU at the qBIC mode in the visible spectral range could be obtained by periodically constructing the metasurface with a unit cell having a lattice constant of 350 nm, a nanohole radius of 160 nm, and a nanohole depth of 250 nm. Furthermore, the study showed that the resonance mode that enabled high sensitivity was the PR mode, with a sensitivity nearly three times larger than that of the qBIC mode and the ability to reach the highest reflectance at the resonance wavelength. The optimized feature had the highest reflectance at a resonant wavelength of 570.19 nm, and although the quality factor was 25.50, these designed parameters were considered sufficient for developing a refractive index biosensor with high sensitivity and optical efficiency when operating in the visible spectral range.

Detection of hemoglobin concentration in human blood samples using a zinc oxide nanowire and graphene layer heterostructure based refractive index biosensor

Detection of hemoglobin concentration in human blood samples using a zinc oxide nanowire and graphene layer heterostructure based refractive index biosensor

An asymmetric slotted structured twin core photonic crystal fiber based highly sensitive surface plasmon resonance refractive index biosensor

A butterfly-shaped core photonic crystal fibers with less asymmetric rectangular and circular air holes are proposed, and their properties are numerically analyzed. The sensor construction is reduced to only seven air holes and uses surface plasmons stimulated inside gold (Au) strips for simplicity in manufacture and high sensitivity. Gold is employed as an effective plasmonic metal throughout this design to create resonant effects and is located away from the proposed structure to make production easier. Maximum amplitude sensitivity for the proposed sensor is 228.89 RIU−1, maximum wavelength sensitivity is 88,000 nm/RIU, and maximum wavelength resolution is 1.14 × 10−6RIU−1 for y-polarized mode where the figure of merit is 65.78 RIU−1 with a linearity of 0.9905. The proposed sensor can detect the RI of unspecified analytes between 1.27 and 1.40, allowing for the analysis of many different types of analytes, such as viruses, cancer cells, sugars, proteins, DNA/RNA and many more.

High-Sensitivity Gold-Coated Refractive Index Biosensor Based on Surface Plasmon Resonance

High-Sensitivity Gold-Coated Refractive Index Biosensor Based on Surface Plasmon Resonance

Refractive index biosensor based on topological ring resonator

The hemoglobin (Hb) concentration in the blood is an important parameter in the field of medical diagnostics. It is no doubt that improving robustness and reducing unnecessary losses needs to be reviewed with special attention in the detection Hb process. Topological ring resonator (TRR) structure based on all-dielectric valley photonic crystals (VPCs) has started to gain the interest of researchers due to its anti-scattering properties and unique immune defect performance. In this paper, we demonstrated Hb concentration detection using the TRR structure based on all-dielectric VPCs. It can be seen that a high transmittance even if there are structural defects of the flat-, Z-, and Ω -shape waveguide when the structure is immersed in water completely. Going further, by using a triangular ring-shaped topological edge coupled to the straight topological edge waveguide, which excites a narrowband high-quality (Q) factor resonance. The strong dependence of the resonant peak on Hb concentration and the consequent refractive index (RI) is the essential bases of the detection process. Results show that the sensitivity of the structure can reach up to 798.39 nm/RIU with a figure of merit (FOM) as high as 725.81 RIU−1 (65 g/L). Due to the high sensitivity and topologically protected nature, the proposed structure has great potential in Hb detection, which is hardly affected by structure imperfections and disorder.

Graphene-Based Metasurface Refractive Index Biosensor for Hemoglobin Detection: Machine Learning Assisted Optimization.

Machine learning is the latest approach to optimize the performance of absorbers, sensors, etc. A sensor with behavior prediction using polynomial regression is presented. Three different variations of metasurfaces namely double split-ring resonator, single split ring resonator, split ring resonator with thin wire are analyzed. The proposed design aims to achieve the highest sensitivity by observing different designs and different parameter variation. The highest sensitivity is achieved for double split-ring resonator and single split ring resonator designs. The change in thickness of different parameter affect the absorption and the highest sensitivity is calculated based on these variations. The polynomial regression (PR) model is employed to predict the absorption values for assorted combinations of intermediate wavelength values with angle variation, substrate thickness, substrate length, substrate width, graphene potential, and resonator thickness values. Test Cases R-30 and R-50 are evaluated using R2 score metric to assess the effectiveness of PR model for predicting the values of absorption. R2 score close to 1.0 is achieved for all the experiments at a higher (more than 5) polynomial degree, which proves the prediction efficiency of a regression model. The proposed biosensor designed with a PR model can be applied in biomedical applications for hemoglobin detection.

Near-infrared refractive detection of newly freshly-excised human-liver tissues: an optical refractive index biosensor based on 2D-photonic crystal

Near-infrared refractive detection of newly freshly-excised human-liver tissues: an optical refractive index biosensor based on 2D-photonic crystal

Detection and Analysis of Bacterial Water using Photonic Crystal Ring-Resonator Based Refractive-Index Sensor on SOI Platform

A refractive-index biosensor is modeled using a photonic crystal ring resonator. The proposed sensor possesses a high selectivity and high quality-factor against different bacterial water samples. The introduction of the circular rim in the ring resonator structure is responsible for a sharp resonance that makes it suitable for detecting bacterial impurities. The sufficiently separated resonant peak for different samples offers a possibility of highly selective label-free bacterial water detection. The proposed biosensor is highly sensitive, real-time, lab-on-chip, and label-free, which is necessary for on-site detection. The proposed sensor is designed using a silicon-on-insulator platform.

Design of a novel refractive index BIOSENSOR for heavy metal detection from water samples based on fusion of spectroscopy and refractive index sensing

This work presents a novel application of a photonic crystal fiber (PCF) based surface plasmon resonance (SPR) biosensor for analyzing heavy metal (HM) fused water samples. An innovative design of the PCF SPR biosensor is shown in this article, having a combination of D− shaped and external metal deposition (EMD) technique. The real-time analysis of the HM fused water samples is performed in this work through a developed spectroscopy-based sensing setup which presents the details about the transmission (%) and absorbance (AU) from the water samples. HM, fused water samples show a change in their refractive index (RI) values for varying HM concentrations. This varying range of RI is generalized to design a RI variation-based biosensor. HM fused water samples show a change in the RI varying from 1.330 to 1.350RIU for HM ions Cd2+, Cu2+, Hg2+ and Pb2+. Thus a highly sensitive biosensor is designed to detect HM from the water sample. Therefore the designed biosensor can be considered an ideal candidate for HM detection from the water samples.

Refractive index sensor with magnified resonant signal

Herein, we theoretically suggest one-dimensional photonic crystal composed of polymer doped with quantum dots and porous silicon. The present simulated design is proposed as a refractive index biosensor structure based on parity-time symmetry. Under the parity-time conditions, the transmittance of the resonant peaks is magnified to be 57,843% for refractive index 1.350, 2725% for 1.390, 2117% for 1.392, 1502% for 1.395, 1011% for 1.399, and 847% for 1.401. By magnification, we can distinguish between different refractive indices. The present design can record an efficiency twice the published designs as clear in the comparison table. Results clear that the sensitivities are 635 nm/RIU and 1,000,000%/RIU. So, it can be used for a broader range of detection purposes.

Refractive Index Biosensor Using Metamaterial Perfect Absorber Based on Graphene in Near-Infrared for Disease Diagnosis

This paper presents a metamaterial perfect absorber as a biosensor in the near-infrared region for biomedical molecular detection, such as urine concentration, malaria infection, bacillus bacteria, and cancer cell detection. In the proposed biosensor, an Au layer with a bracket-shaped cavity is utilized to boost electric field enhancement intensity in the vicinity of the nanohole. According to the capacitance of the bracket-shaped nanohole, changing the length of the hole controls the resonance wavelength. Due to the significant confinement of the electromagnetic field in the sharp edges and gaps, which excites Localized Surface Plasmon Resonances (LSPRs) in the metal-dielectric interface, near-unity absorption is obtained. Through evaluating the optical responses of the structure, via the finite element method (FEM), for different biomedical samples, high sensitivity of 2120.86 nm/RIU is acquired. In order to increase the sensitivity of the biosensor, a graphene layer is added between the dielectric layer and the gold nanohole layer. Adding graphene increases the LSPRs excitation and losses which yields a maximum sensitivity of 2500 nm/RIU. The presented biosensor with high sensitivity and compact size is a good candidate for biomedical purposes.