Fiber Surface Plasmon Resonance Biosensor Research Articles

Smartphone-based selective and sensitive detection of vitamin B1 in synthetic urine using U-bend SPR optical fiber probe

This paper introduces an innovative optical fiber surface plasmon resonance (SPR) biosensor designed for smartphone assistance, aiming at detecting vitamin B1 in synthetic urine. The key novelty lies in the amalgamation of silver nanocoated cysteine with a gold-plated optical fiber probe, fostering efficient detection through the robust electrostatic interaction between negatively charged Cys-capped AgNPs and positively charged vitamin B1 molecules. Notably, this biosensor leverages the smartphone's digital camera capabilities to discern varying color intensities. A self-developed application ensures real-time monitoring of green and red channel intensities in the SPR signal, thereby mitigating the risk of false detections. Moreover, the integration of the fabricated optical fiber probe with the smartphone is achieved through a 3D-printed casing, endowing the biosensor with the advantages of portability, handheld operation, and cost-effectiveness. The proposed U-shaped optical fiber SPR biosensor, coupled with smartphone technology, demonstrates the ability to detect vitamin B1 within the concentration range of 2–10 μM, yielding a commendable R2 value of 0.9973. Experimental findings affirm that this novel biosensor, built on the U-shaped SPR optical fiber architecture and empowered by smartphones, is an economical, uncomplicated, and portable device adept at accurately and efficiently detecting vitamin B1 across a broad concentration spectrum. Its potential applications extend to the area of low-cost biochemical component identification.

Numerical study of a D-shaped optical fiber SPR biosensor for monitoring refractive index variations in biological tissue via a thin layer of gold coated with titanium dioxide

This study aims to explore the numerical analysis of the impact of integrating titanium oxide (TiO2) into a D-shaped optical fiber biosensor based on surface plasmon resonance (SPR). A thin layer of gold (Au) is applied to the flat section of the fiber, which is also coated with a thin layer of titanium dioxide (TiO2). The behavior and performance of the proposed biosensor for use in biological environments are evaluated using the finite element method (FEM). The optical response of SPR-based biosensors is highly dependent on the analyzed medium, enabling the detection of pathogenic cells and abnormalities in biological tissues. This provides high sensitivity and selectivity, as well as real-time detection accuracy and speed. In this study, the biosensor is incorporated into a biological medium with a refractive index that varies with wavelength. A series of simulations have been conducted to plot the spectra of transmissions, absorptions, and dielectric losses obtained in the output of the sensor instrument. From these spectra, the corresponding surface plasmon resonance (SPR) wavelength (λSPR) within the visible-near-infrared band can be determined. Taking into account the various parameters that influence plasmonic interactions, the biosensor's performance parameters, in particular sensitivity and refractive index resolution have been optimized. Our results show that the presence of the TiO2 layer improves the performance of the proposed sensor and offers the possibility of adjusting the resonance wavelength (λSPR). In addition, our proposed sensor can achieve a better resolution of 7.50×10-6[RIU] in 1.34-143 range of analyte refractive index, which notably exceeds that of current technologies. This opens up new prospects in the field of chemical and biological detection.

Optical fiber SPR biosensor with frequency multiplexing compensated laser heterodyne feedback for ultrasensitive detection of fluoroquinolones

The widespread usage and discharge of fluoroquinolones (FQs) have caused negative environmental consequences that can threaten human health. The development of ultrasensitive and simple devices for detection of various FQs is an important requirement. Here, we proposed a novel optical fiber surface plasmon resonance biosensor to achieve the ultrasensitive detection of FQs, in which the frequency-shifted light returned to the laser resonator and stimulated laser heterodyne feedback interferometry to amplify the intensity changes caused by the refractive index (RI) variations. In addition, we further presented a quasi-common path frequency multiplexing compensation method to compensate for the noise of the developed biosensor, resulting in a RI resolution of 1.06 × 10−6 RIU. Besides, the gold nanorods were used to generate localized surface plasmon resonance to further amplify the signal to achieve the ultrasensitive detection. A variety of FQs were detected with ultra-low detection limits, including enrofloxacin (0.61 ng/L), ciprofloxacin (0.54 ng/L), norfloxacin (0.31 ng/L), pefloxacin (0.32 ng/L), and sarafloxacin hydrochloride (0.97 ng/L). With the advantages of high sensitivity, compact size, and remote operation capability, the developed biosensor holds the promise of detecting other antibiotics with universality in hard-to-reach spaces, thus having the potential to demonstrate a promising approach to environmental monitoring.

Optical fiber SPR biosensor with a solid-phase enzymatic reaction device for glucose detection

A portable and user-friendly optical fiber sensing platform for rapid glucose detection based on surface plasmon resonance (SPR) sensing and enzymatic reaction is proposed. We designed a simple and easy-to-use miniaturized device for the specific decomposition of glucose; the device can fully react with glucose samples and produce glucose-free samples. The optical fiber SPR biosensor was prepared for detecting glucose samples before and after enzymatic reaction through the device, and to obtain an SPR differential signal that corresponds specifically to glucose concentration. Different levels of urine glucose concentrations in a broad range of 0–400 mg/dL were distinguished by the proposed method with a sensitivity of 3.10 pm/(mg/dL). Our novel method has the following advantages: (1) the sensor and enzymatic reaction device can be reused with low cost; (2) the interference of the background solution can be eliminated for more specific glucose detection; (3) the operation is simple and fast without requiring professional operation skills, and the test samples can be directly loaded/released for detecting; (4) the platform is also suitable for the specific detection of other enzymatic reactions by changing the reaction enzyme. The platform provides a new pathway for the detection of food additives and medical immunoassays.

Plug-in optical fiber SPR biosensor for lung cancer gene detection with temperature and pH compensation

A novel DNA hybridization optical fiber sensor with temperature and pH compensation for detecting a common lung cancer gene of epidermal growth factor receptor (EGFR) gene was demonstrated in this paper. The paper proposes the first research to achieve dual surface plasmon resonance (SPR) in an Fiber Bragg grating (FBG) and implement a three-parameter detection of DNA sequence, temperature and pH using a single fiber. Probe DNA sequences (pDNA) and PAA/CS, a pH-sensitive material, are immobilized on the sensor surface for EGFR gene exon-20 detection and temperature and pH monitoring simultaneously. The effectiveness of this functionalized method has been proved by using an atomic force microscope (AFM) and scanning electron microscope (SEM). The limit of detection (LOD) of EGFR gene was experimentally verified to 13.5 nM. The advantages of fast response, high sensitivity, label free, plug in, low LOD and three-parameter detection demonstrated by this sensor in the experiment are important for the field of DNA hybridization research and solving the problems of biosensor susceptibility to temperature and pH.

Optical fiber SPR biosensor complying with a 3D composite hyperbolic metamaterial and a graphene film

In the present study, an optical fiber surface plasmon resonance (SPR) biosensor was developed for measuring time- and concentration-dependent DNA hybridization kinetics. Its design complies with a 3D Au / Al 2 O 3 multilayer composite hyperbolic metamaterial (HMM), a graphene film, and a D-shaped plastic optical fiber. According to the numerical simulation and the experimental demonstration, the SPR peak of the designed biosensor can be effectively altered in the range of visible to near-infrared by varying the HMM structure. The sensitivity of the appliance was shown to achieve a value of up to 4461 nm/RIU, allowing its applicability for bulk refractive index sensing. Furthermore, a biosensor designed in this work displayed high-resolution capability (ranging from 10 pM to 100 nM), good linearity, and high repeatability along with a detection limit down to 10 pM, thus suggesting a vast potential for medical diagnostics and clinical applications.

An Au Nanofilm-Graphene/D-Type Fiber Surface Plasmon Resonance Sensor for Highly Sensitive Specificity Bioanalysis

A highly sensitive Au-graphene structure D-type fiber surface plasmon resonance biosensor is presented in this study to specifically detect biomolecules. The method of growing graphene is employed directly on the copper, and then a gold film of optimum thickness is sputtered, and the copper foil is etched to obtain the structure. This method makes the contact closer between the gold layer and the graphene layer to improve surface plasmon resonance performance. The performance of this type of surface plasmon resonance (SPR) sensor has been previously verified both theoretically and experimentally. With the proposed Au-graphene structure D-type fiber biosensor, the SPR behaviors are obtained and discussed. In the detection of ethanol solution, a red shift of 40 nm is found between the refractive index of 1.3330 and 1.3657. By calculation, the sensitivity of the sensor we designed is 1223 nm/RIU. Besides, the proposed sensor can detect the nucleotide bonding between the double-stranded DNA helix structures. Thus, our sensors can distinguish between mismatched DNA sequences.

MoSe2-Au Based Sensitivity Enhanced Optical Fiber Surface Plasmon Resonance Biosensor for Detection of Goat-Anti-Rabbit IgG

Surface Plasmon resonance (SPR) provides an efficacious and label-free detection method for optical fiber bio-sensing. MoSe 2 is one of the transition metal dichalcogenides (TMDCs) which has broad applications in detecting specific reactions. Cysteamine hydrochloride with enriched groups can generate self-assemble films for tight attachment. In this study we aimed to combine the rapid response of optical fiber SPR sensors with the enhanced sensitivity of MoSe 2 nano-films. An optical fiber SPR biosensor with MoSe 2 -Au nanostructure was proposed and implemented, and a sensitivity of 2821.81 nm/RIU was achieved, which was approximately 98.7% higher than that of conventional SPR sensor without using MoSe 2 nanostructure. Furthermore, Bovine Serum Albumin (BSA) was utilized as the target molecule to test the bioaffinity of the biosensor with MoSe 2 deposition cycles from 0 to 8. Weighing the sensitivity and the figure of merit (FOM), the best deposition cycle of MoSe 2 was 4 with the sensitivity of 2793.36 nm/RIU and FOM of 37.24 RIU -1 . At last, immunization experiments were carried out using Goat-anti-Rabbit IgG and a detection limit of 0.33 μg/mL was achieved. The rapid response and the high bioaffinity showed a strong applicability of the proposed MoSe 2 -Au SPR immune-sensor in specific interactions and immunization therapy.

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.

D-Shaped photonic crystal fiber biosensor based on silver-graphene

A D-shaped photonic crystal fiber surface plasmon resonance biosensor is presented with high sensitivity. Determinand are used outside the fiber structure to realize a simple detection mechanism. The sensor consists of photonic crystal fiber, graphene and metal. The sensitivity of the sensor is enhanced by graphene between the silver layer and D-shaped photonic crystal fiber. The two small air holes in the center of the photonic crystal fiber are beneficial to the phase matching of the core and the plasmon polaritons. The two large air holes are beneficial to the birefringence and the coupling of polarized light with metal. The Full vector finite element method is used to numerical simulation and analysis the transmission mode and characteristics of the photonic crystal fiber surface plasmon resonance biosensor. In the range of refractive index is 1.34–1.40, the average sensitivity of the sensor is 4850 nm/RIU with a high resolution of 2 × 10−5RIU. The minimum full width at half maximum is 10 nm. The proposed sensor can be applied to real-time detection of the biomolecules and small drug-molecules due to the advantages of long distance transmission, high sensitivity and high resolution.

An optical fiber surface plasmon resonance biosensor for wide range detection

An optical fiber surface plasmon resonance biosensor is presented that allows to numerically demonstrate, using transfer matrix method and the finite difference time domain method, the detection range is very wide. Two different structures of graphene photonic crystal multilayer (i.e. sensor I and sensor II) are constructed in the cladding region of single-mode fiber. Graphene is used as the plasma layer instead of the traditional metal. According to the analysis, the properties of graphene can be changed by adjusting the chemical potential µ c . In the spectral region of 1.667| µ c | ћω µ c |, the imaginary part of conductivity σ ″ becomes negative. Thus the weakly bounded low-less TE-SPR is supported by graphene. The results of the numerical simulation show that the relationship between refractive index and resonant wavelength is linear. The sensor I can detect the refractive index range of 1.33–1.4, and the sensitivity is 1942 nm/RIU. The sensor II can detect the refractive index range of 1.41–1.67, and the sensitivity is up to 2315.4 nm/RIU. Therefore, the detection of wide refractive index range of 1.33–1.67 or simultaneous detection of different biological medium concentration is realized by the sensor.

Copper-Graphene-Based Photonic Crystal Fiber Plasmonic Biosensor

We propose a photonic crystal fiber surface plasmon resonance biosensor where the plasmonic metal layer and the sensing layer are placed outside the fiber structure, which makes the sensor configuration practically simpler and the sensing process more straightforward. Considering the long-term stability of the plasmonic performance, copper (Cu) is used as the plasmonic material, and graphene is used to prevent Cu oxidation and enhance sensing performance. Numerical investigation of guiding properties and sensing performance is performed by using a finite-element method. The proposed sensor shows average wavelength interrogation sensitivity of 2000 nm/refractive index unit (RIU) over the analyte refractive indices ranging from 1.33 to 1.37, which leads to a sensor resolution of $5\times 10^{-5} \text{RIU}$ . Due to the simple structure and promising results, the proposed sensor could be a potential candidate for detecting biomolecules, organic chemicals, and other analytes.

Temperature-Compensating Fiber-Optic Surface Plasmon Resonance Biosensor

A temperature-compensating fiber-optic surface plasmon resonance (SPR) biosensor based on a Fabry–Perot (FP) interference is described and demonstrated in this letter. The sensing element includes an SPR measuring signal and an FP referencing signal, which appear on gold-coated multimode fiber and capillary, respectively. Because the FP sensing element is sensitive to temperature while insensitive to the refractive index, the referencing channel compensates for the impact of external ambient temperature and enhances the accuracy and reliability of the biosensor. The performance of the temperature-compensating SPR biosensor for accurate measurements is evaluated through the specific binding between Con A and RNase B under interference temperature. In addition, the design and fabrication of the temperature-compensating fiber SPR biosensor are cost effective and simple.

Optical fiber SPR biosensor with sandwich assay for the detection of prostate specific antigen

We present a new, sensitive, few mode fiber (FMF) surface plasmon resonance (SPR) biosensor with a sandwich assay for the detection of PSA. The side-polished FMF biosensor does not need a polarizer and a thin high-index overlayer. The optical sensitivity of the SPR sensor was determined as 2.5 × 10 −6 RIU. In the SPR PSA sensor, the SPR signals were amplified by a factor of 6 in average over no secondary antibody, using the sandwich assay. The proposed FMF SPR biosensor has great potential for real-time analysis of immune reaction between biomolecules and the advantages of high-sensitivity and label-free detection.