Sensitive Surface Plasmon Resonance Biosensor Research Articles

Rapid and Sensitive Detection by Combining Electric Field Effects and Surface Plasmon Resonance: A Theoretical Study.

Surface plasmon resonance (SPR) has been extensively employed in biological sensing, environmental detection, as well as chemical industry. Nevertheless, the performance possessed by conventional surface plasmon resonance (SPR) biosensors can be further limited by the transport of analyte molecules to the sensing surface, noteworthily when small molecules or low levels of substances are being detected. In this study, a rapid and highly sensitive SPR biosensor is introduced to enhance the ability of the target analytes' collection by integrating AC electroosmosis (ACEO) and dielectrophoresis (DEP). Both the above-mentioned phenomena principally arise from the generation of the AC electric fields. This generation can be tailored by shaping the interdigitated electrodes (IDEs) that also serve as the SPR biomarker sensing area. The effects exerted by different parameters (e.g., the frequency and voltage of the AC electric field as well as microelectrode structures) are considered in the iSPR (interdigitated SPR) biosensor operation, and the iSPR biosensors are optimized with the sensitivity. The results of this study confirm that the iSPR can efficiently concentrate small molecules into the SPR sensing area, such that SPR reactions achieve an order of magnitude increase, and the detection time is shortened. The rapid and sensitive sensor takes on critical significance in the development of on-site diagnostics in a wide variety of human and animal health applications.

Sensitive surface plasmon resonance biosensor by optimized carboxylate functionalized carbon nanotubes/chitosan for amlodipine detecting

The adoption of biophotonic sensing technologies holds significant promise for application in health care and biomedical industries in all aspects of human life. Then, this piece of writing employs the powerful effective medium theory and FDTD simulation to anticipate the most favorable state and plasmonic attributes of a magnificent nanocomposite, comprising carboxylate functionalized carbon nanotubes and chitosan (CS). Furthermore, it thoroughly explores the exhibited surface plasmon resonance behaviors of this composite versus the quantity of CS variation. Subsequently, enlightening simulations are conducted on the nanocomposite with a delicate layer and a modified golden structure integrating as a composite. The intricate simulations eventually unveil an optimal combination to pave the way for crafting an exceptional specific biosensor that far surpasses its counterpart as a mere Au thin layer in terms of excellence. The proposed biosensor demonstrated linear behavior across a wide range from 0.01 μM to 150 μM and achieved a detection limit of 10 nM, with a sensitivity of 134◦RIU−1.

Investigation of Highly Sensitive Surface Plasmon Resonance Biosensor Employing Black Phosphorous and Graphene Hybrid Structure

Investigation of Highly Sensitive Surface Plasmon Resonance Biosensor Employing Black Phosphorous and Graphene Hybrid Structure

Surface Plasmon Resonance Sensor Based on Core-Shell Fe3O4@SiO2@Au Nanoparticles Amplification Effect for Detection of T-2 Toxin

In this paper, a core-shell based on the Fe3O4@SiO2@Au nanoparticle amplification technique for a surface plasmon resonance (SPR) sensor is proposed. Fe3O4@SiO2@AuNPs were used not only to amplify SPR signals, but also to rapidly separate and enrich T-2 toxin via an external magnetic field. We detected T-2 toxin using the direct competition method in order to evaluate the amplification effect of Fe3O4@SiO2@AuNPs. A T-2 toxin-protein conjugate (T2-OVA) immobilized on the surface of 3-mercaptopropionic acid-modified sensing film competed with T-2 toxin to combine with the T-2 toxin antibody-Fe3O4@SiO2@AuNPs conjugates (mAb-Fe3O4@SiO2@AuNPs) as signal amplification elements. With the decrease in T-2 toxin concentration, the SPR signal gradually increased. In other words, the SPR response was inversely proportional to T-2 toxin. The results showed that there was a good linear relationship in the range of 1 ng/mL~100 ng/mL, and the limit of detection was 0.57 ng/mL. This work also provides a new possibility to improve the sensitivity of SPR biosensors in the detection of small molecules and in disease diagnosis.

Simulation study of reconfigurable surface plasmon resonance refractive index sensor employing bismuth telluride and MXene nanomaterial for cancer cell detection

In this study, a highly angular sensitive surface plasmon resonance (SPR) biosensor has been designed for cancer cell detection. The proposed surface plasmon resonance biosensor structure is based on Kretschmann configuration, which works on an angular interrogation technique. The proposed SPR biosensor has enormous possibility to detect the various kind of cancer cells. The refractive index alteration of different cancerous (skin, cervical and blood) cells is 1.360–1.390. The proposed SPR biosensor is stacked with multilayers having CaF2 prism, silver metal, bismuth telluride (Bi2Te3) and MXene (Ti3C2Tx) layers. The performance parameters like angular sensitivity, quality factor, detection accuracy, and electric field intensity distribution have been optimized in this article. Here, various kind of cancer cells (skin, cervical and blood) have been also analyzed and corresponding angular sensitives are 252.20, 305.70 and 319.46 deg R−1IU−1 respectively. The proposed SPR biosensor shows best results for blood cancer cell detection. Some other important performance parameters like detection accuracy, quality factor, and electric field intensity distribution have also been calculated for proposed SPR biosensor device. The simulation results have been performed by MATLAB 2019a software. The proposed SPR biosensor design may open a new way for the medical industry.

Theoretical and experimental study of a highly sensitive SPR biosensor based on Au grating and Au film coupling structure.

A high-sensitivity surface plasmon resonance (SPR) sensor based on the coupling of Au grating and Au film is investigated through simulations and experiments. The SPR sensor is designed by using a hybrid method composed of genetic algorithm (GA) and rigorous coupled wave analysis (RCWA). The numerical results indicate the sensor has an angular sensitivity of 397.3°/RIU (refractive index unit), which is approximately 2.81 times higher than the conventional Au-based sensor and it is verified by experiments. Theoretical analysis, by finite-difference time-domain (FDTD) method, demonstrates the co-coupling between surface plasmon polaritons (SPPs) propagating on the surface of Au film and localized surface plasmons (LSPs) in the Au grating nanostructure, improving the sensitivity of the SPR sensor. According to the optimized structural parameters, the proposed sensor is fabricated using e-beam lithography and magnetron sputtering. In addition, the proposed sensor is very sensitive to the detection of small molecules. The limit of detection (LOD) for okadaic acid (OA) is 0.72 ng/mL based on an indirect competitive inhibition method, which is approximately 38 times lower than the conventional Au sensor. Such a high-sensitivity SPR biosensor has potential in the applications of immunoassays and clinical diagnosis.

A study on surface plasmon resonance biosensor for the detection of CEA biomarker using 2D materials graphene, Mxene and MoS2

In this work, A surface plasmon resonance (SPR) biosensor is designed for the selective detection of carcinoembryonic antigen (CEA) present in the sensing medium (PBS solution) using three kinds of 2D materials i.e. graphene, molybdenum disulfide (MoS2) and mxene. Initially we introduce a basic design of Ti-Ag-Graphene based SPR biosensor for detection of CEA. After that, include the mxene and MoS2 layer between silver and graphene layer in basic Ti-Ag-Graphene structure separately for performance enhancement and also for comparative analysis. Over the graphene layer, bovine serum albumin (BSA) is deposited for the selective attachment of CEA biomarkers present in PBS solution in all structures. We find that the performance parameters are improved by the introduction of MoS2 and mxene as sandwiched between silver and graphene layers. The proposed design shows maximum sensitivity 144.72 deg./RIU and detection accuracy 2.24 for MoS2-Graphene based structure, which is better than other reported works. A comparative study shows that the MoS2-Graphene combination shows better performance as compared to Mxene-Graphene combination. This study may prove their importance to enhancement in sensitivity of SPR biosensors by using these 2D materials.

Affinity-Based Nanoarchitectured Biotransducer for Sensitivity Enhancement of Surface Plasmon Resonance Sensors for In Vitro Diagnosis: A Review.

Despite the indisputable benefits and advancement of science, technology, and civilization, early diagnosis of healthcare is still a challenging field for the scientific fraternity. The detection of biomarkers is a crucial attribute of prognosis and diagnosis of disease. Out of numerous techniques, surface plasmon resonance (SPR) bestows countless benefits, including in situ, label-free, and real-time assessment, etc., which authorizes the analysis of molecular binding occurrences between biotransducers and biomarkers. In addition, SPR with low-molecular-weight biomarkers lacks selectivity and sensitivity, which ultimately affects binding kinetics. This, in turn, leads to the remarkable development and implementation of numerous selectivity and sensitivity enhancement methods. Among the various noticeable strategies, because of selectivity and sensitivity enrichment substrate for SPR biosensors, affinity-based nanoarchitectured biotransducers stand out as being the best substitute. The present review elaborates significant advances made in the research based on affinity biotransducers for in vitro diagnosis using SPR biosensors for biomarker sensing. Moreover, most recent trends and challenges in designing and application of nanoarchitectured affinity biotransducer-based SPR biosensors for detecting low-concentration biomarkers have been reviewed comprehensively. This present review may assist the scientific fraternity in designing an ultramodern novel SPR approach based on affinity biotransducers, along with improved selectivity and sensitivity of SPR biosensors for in vitro and real-time diagnostic applications.

Application of Gold and Platinum Bimetallic Nanoparticle to enhance Surface Plasmon Resonance Signal

Sensors based on the surface plasmon resonance (SPR) technique are useful devices to detect and monitor interactions between biomolecules in real-time. SPR is a label-free method that monitors the variation of reflectivity of a biochip composed of a metal-coated glass prism and can be applied in several areas, such as biotechnology, food safety and clinical diagnosis. In the last years, several researchers have proven the efficiency of metallic nanoparticles (NPs) in the enhancement of SPR signal. This feature allowed the detection of biomolecules at very low concentration. Aiming to further enhance SPR signal towards the detection of proteins at low concentration and by a simple procedure, the present work compared the performance of gold and platinum bimetallic NPs (AuPtNPs) with that of monometallic gold NPs (AuNPs) in the enhancement of SPR signal. In order to evaluate the NPs, protein peanut agglutin (PNA) was used as target analyte and anti-PNA antibody was used as sensing molecule. Firstly NPs were functionalized with anti-PNA antibody and incubated with a solution containing PNA. Then, the NPs bound to PNA were injected into the SPR equipment containing a biochip previously modified with anti-PNA antibody. The results demonstrated that the AuPtNPs provided a 91-fold increase compared to the direct detection of free PNA in solution. In comparison with AuNPs, the signal generated by AuPtNPs was about 4 times higher. This encouraging result indicated that the application of bimetallic NPs may be a better strategy to further enhance sensitivity of SPR biosensors and could drive the development of new strategies that are not only simple, but also able to detect proteins at low concentrations, which is of great importance, especially in clinical diagnostics.

Modeling of highly sensitive surface plasmon resonance (SPR) sensor for urine glucose detection

This work presents a novel structure of surface plasmon resonance (SPR) sensor for urine glucose detection. The structure consists of four layers namely gold, molybdenum disulfide (MoS2), h-BN (hexagonal boron nitride), and graphene. Here, the few-layer h-BN is used as a capping layer over the MoS2 layer. The present sensor performance has been evaluated for sensitivity, quality parameter, resonance angle shift, and accuracy of detection. Sensitivity for urine glucose concentration of 0–15 mg/dl (normal range), 0.625 g/dl, 1.25 g/dl, 2.5 g/dl, 5 g/dl and 10 g/dl are found to be 180 degree/RIU, 183.34 degree/RIU, 185.71 degree/RIU, 187.5 degree/RIU, 190.9 degree/RIU and 194.12 degree/RIU respectively. The corresponding values of quality parameters and detection accuracy are observed 14.88 /RIU, 15.15 /RIU, 15.35 /RIU, 15.5 /RIU, 15.78 /RIU, 16.04 /RIU and 0.07448, 0.09091, 0.10744, 0.12397, 0.17355, 0.27273 respectively. Hence, these enhanced performances of the present SPR biosensor makes this structure suitable for urine glucose detection as well as open a new platform in the field of medical science.

BaTiO3-Graphene-Affinity Layer–Based Surface Plasmon Resonance (SPR) Biosensor for Pseudomonas Bacterial Detection

In the present work, a highly sensitive SPR biosensor based on silver (Ag), barium titanate (BaTiO3), graphene, and affinity layer is proposed for the detection of Pseudomonas bacteria. The performance of this proposed sensor has been numerically studied and analyzed for sensitivity, quality parameter, and detection accuracy. The proposed structure used attenuated total reflection (ATR) approach based on the Kretschmann configuration for the investigation of performance parameters. The inclusion of the BaTiO3 layer along with the affinity layer shows the enhancement in the performance of the proposed structure for the detection of Pseudomonas bacteria. A comparison of the proposed structure is drawn with contemporary surface plasmon resonance (SPR) biosensors for the detection of Pseudomonas bacteria, and better performance was shown. This work reports that the maximum sensitivity, quality parameter, and detection accuracy for the proposed sensor are 220 degree/RIU, 101.38 RIU−1, and 7.09 respectively. Therefore, the proposed design finds its application in Pseudomonas bacterial detection as well as opens a new window in the biosensing area.

Performance comparison of surface plasmon resonance biosensors based on ultrasmall noble metal nanoparticles templated using bovine serum albumin

Due to their excellent chemical stability, biocompatibility, ease of modification and unique optical properties, ultrasmall noble metal nanoparticles (size 1–2 nm) are finding increasing application in the biomedical sector, in particular as cell markers and bioimaging agents. Herein, the unexplored potential of ultrasmall noble metal nanoparticles as sensitizers in surface plasmon resonance (SPR) biosensors is critically examined. Three types of bovine serum albumin (BSA) coated ultrasmall noble metal nanoparticles were synthesized (BSA-Au NPs, BSA-Au/Ag NPs and BSA-Ag NPs), with the effect of these different types of nanoparticles on the sensitivity of a SPR biosensor for the detection of the enzyme papain explored. Results show that the sensitivity of SPR biosensors containing BSA-Au NPs, BSA-Ag NPs or BSA-Au/Ag NPs BSA were 1.9, 2.6 and 3.6 times higher, respectively, than a control SPR biosensor (BSA only). The remarkable sensitizing properties of the ultrasmall noble metal nanoparticles, especially the BSA-Au/Ag NPs, related to their unique size dependent optical properties.

Design and Simulation of a High Sensitive Surface Plasmon Resonance Biosensor for Detection of Biomolecules

In this paper, a surface plasmon resonance (SPR) biosensor based on black phosphorus (BP)–WSe2 coated metal surface for the detection of biomolecules is designed and simulated. The reported sensor configuration consists of a prism (SF10 glass), ZnO (zinc oxide), gold (Au), WSe2–BP, and sensing medium. The execution parameters including sensitivity, detection accuracy, and quality factor of the proposed sensor are explored at an operating wavelength of 633 nm. The angular interrogation method is used for the reflectance spectra analysis. The overall simulation is performed by COMSOL multiphysics (5.3a). Numerical outcomes demonstrate that the base ZnO layers which have an expansive genuine value of the dielectric constant in a mix with gold, WSe2, and BP are in charge of upgrading the detecting execution of the proposed SPR based biosensor. The reported biosensor achieves maximum sensitivity of 101.5 deg/RIU, the detection accuracy of 1.57 and a quality parameter of 15.62 RIU−1 for a large dynamic range of refractive index differing from 1.33 to 1.43.

Highly Sensitive SPR Biosensor Based on Graphene Oxide and Staphylococcal Protein A Co-Modified TFBG for Human IgG Detection

A highly sensitive optical fiber surface plasmon resonance (SPR) biosensor based on graphene oxide (GO) and staphylococcal protein A (SPA) co-modified tilted fiber Bragg grating (TFBG) is proposed and demonstrated for the detection of human immunoglobulin G (IgG) for the first time. The gold film on the surface of the sensor was first fixed with GO and then modified with an SPA to improve the sensitivity of the sensor. Large specific surface area and abundant functional groups of GO can adsorb more antibodies. The combination of SPA and the antibody molecule Fc region makes the Fab area with antigen-binding sites extend outward, resulting in highly oriented antibody immobilization on the sensor surface and high antigen–antibody binding efficiency. The experimental results show that the sensitivity as well as the limit of detection of GO-SPA-modified TFBG-SPR biosensor is around 0.096 dB/( $\mu \text{g}$ /mL) and $0.5~\mu \text{g}$ /mL, showing better responses to human IgG solutions with a concentration range of 30– $100~\mu \text{g}$ /mL compared with the TFBG-SPR biosensors modified singly with GO or SPA. The biosensor exhibits the advantages of small size, ease of fabrication, high sensitivity, label-free, and rapid response, and provides a new solution for detecting low concentration of biological solution, presenting great application potential in the biochemistry field.

Design and numerical analysis of a graphene-coated fiber-optic SPR biosensor using tungsten disulfide

This article provides a simple hybrid design and rigorous numerical analysis of a fiber optic–based surface plasmon resonance (SPR) biosensor for DNA hybridization. The sensor core and both sides of the cladding are constructed with optical fiber, whereas the middle portion of the cladding is filled with the proposed hybrid of silver, tungsten disulfide (WS2), graphene, and a sensing medium. To the best of our knowledge, this is the first demonstration of such a highly sensitive SPR biosensor using WS2 for sensing DNA hybridization. The sensitivity, detection accuracy, and figure of merit are considered as the performance parameters and are analyzed in detail. The analyses reveal an impressive enhancement of the overall performance of the proposed sensor. Insertion of a WS2 layer between silver and graphene provides a sensor with sensitivity higher than that of other sensors reported to date. Additionally, concurrent improvement of all performance parameters is shown by this hybrid sensor, which is not the case for sensors based only on graphene. An increased number of graphene-only layers increases the sensitivity and decreases the detection accuracy and figure of merit. 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. Therefore, the proposed biosensor opens a new window toward detection of biomolecular interactions.

Enhancement in sensitivity of graphene-based zinc oxide assisted bimetallic surface plasmon resonance (SPR) biosensor

In the present communication, a highly sensitive surface plasmon resonance (SPR) biosensor with Kretschmann configuration having alternate layers, prism/zinc oxide/silver/gold/graphene/biomolecules (ss-DNA) is presented. The optimization of the proposed configuration has been accomplished by keeping the constant thickness of zinc oxide (32 nm), silver (32 nm), graphene (0.34 nm) layer and biomolecules (100 nm) for different values of gold layer thickness (1, 3 and 5 nm). The sensitivity of the proposed SPR biosensor has been demonstrated for a number of design parameters such as gold layer thickness, number of graphene layer, refractive index of biomolecules and the thickness of biomolecules layer. SPR biosensor with optimized geometry has greater sensitivity (66 deg/RIU) than the conventional (52 deg/RIU) as well as other graphene-based (53.2 deg/RIU) SPR biosensor. The effect of zinc oxide layer thickness on the sensitivity of SPR biosensor has also been analysed. From the analysis, it is found that the sensitivity increases significantly by increasing the thickness of zinc oxide layer. It means zinc oxide intermediate layer plays an important role to improve the sensitivity of the biosensor. The sensitivity of SPR biosensor also increases by increasing the number of graphene layer (upto nine layer).

Highly sensitive surface plasmon resonance biosensor based on a low-index polymer optical fiber.

A highly sensitive refractive index sensor based on surface plasmon resonance in a side-polished low-index polymer optical fiber is proposed for biosensing. Benefitting from the low refractive index of the fiber core, the sensitivity of the device can reach ~44567 nm/RIU theoretically for aqueous solutions, at the expense of a lowered upper detection limit that is down to ~1.340. The sensor is fabricated by coating 55-nm-thick Au-film on the polished surface of a graded-index perfluorinated polymer optical fiber. Results show that the sensor exhibits a sensitivity of ~22779 nm/RIU at 1.335 with a figure of merit of 61.2. When employed for glucose sensing, the sensor presents an averaged sensitivity of 24.50 nm/wt%, or 0.46 nm/mM. This device is expected to have potential applications in cost-effective bio- and chemical-sensing.

A sensitive SPR biosensor based on hollow gold nanospheres and improved sandwich assay with PDA-Ag@Fe3O4/rGO

A novel surface plasmon resonance (SPR) biosensor based on hollow gold nanospheres (HGNPs) and an improved sandwich assay was developed to detect rabbit IgG. The electromagnetic coupling between the HGNPs and Au film, and the notable plasmonic fields spread over the inner and outer surfaces of HGNPs, led to the considerable amplification of the SPR signal. Polydopamine-Ag@Fe3O4/reduced graphene oxide (PDA-Ag@Fe3O4/rGO) was introduced to bind detection antibody (Ab2) to form the improved sandwich structure. Ag nanoparticles were excited to produce SPR and their hot electrons were doped on graphene thin films, which amplified the response of biomolecules. Magnetic nanoparticles (Fe3O4) simplified the collection of Ab2-PDA-Ag@Fe3O4/rGO. An external layer of polydopamine (PDA) permitted the efficient immobilization of Ab2 without activation via abundant functional groups and protected the nanoparticles from etching or agglomeration. In addition, because of its large mass, Ab2-PDA-Ag@Fe3O4/rGO also played a key role in the further amplification of the SPR response signals. This novel SPR biosensor exhibited an effective response to the rabbit IgG at the different concentrations ranging from 0.019 to 40.00μgmL−1. This value is 132 times lower than that observed for a traditional SPR biosensor based on Au-3-mercaptopropionic acid and 8 times lower than that obtained from an Ab2 sandwich assay, which indicates that the SPR sensor has high sensitivity. In addition, the designed biosensor showed satisfactory recoveries to detect the rabbit IgG spiked in serum samples. Therefore, the novel SPR biosensor with high sensitivity and acceptable recovery has potential for practical applications.

Sensitivity enhancement of graphene coated surface plasmon resonance biosensor

In this paper, a highly sensitive surface plasmon resonance biosensor is presented using angular interrogation. Due to low sensitivity of conventional biosensor, graphene/two-dimensional transition metal are used in surface plasmon resonance biosensor to improve the sensitivity. Here, we propose a seven layer model of biosensor which shows by incorporating silicon layer in addition of transition metal dichalcogenides MoS2 and graphene, the sensitivity of the proposed SPR biosensor can be greatly enhanced than the conventional gold film SPR sensors. It is observed that the highest sensitivity can be obtained by optimizing the structure with 8 nm thickness of silicon layer, one layer of MoS2 and one layer of graphene. The highest sensitivity of our proposed sensor is 210°/RIU.

A highly sensitive surface plasmon resonance biosensor using photonic crystal fiber filled with gold nanowire encircled by silicon lining

The proposed photonic crystal fiber structure senses small deviations in the refractive index of liquids by surface plasmon resonance phenomenon. The coupling of core guided mode to surface plasmon polariton modes is modulated by the analyte placed between the central core and gold nanowire. Numerical study on the sensor performance is executed using finite element method. A sensitivity of 2000nm/RIU is achievable for detection of liquids with refractive index greater than 1.37 and the sensor covers a wide sensing range from 1.37 to 1.45. Loss factors as high as 187.76dB/cm is achievable. The analysis on the influence of structural modifications such as increase and decrease of gold nanowire diameter on the sensing action is also carried out. Numerical results depict an increase in confinement loss factor as the gold diameter gets reduced and a shift towards longer wavelength. The analysis of the sensor performance is performed when the gold nanowire is coated with silicon and it reveals that the loss factor gets enhanced by three fold, from 115.88 to 360.81dB/cm for analyte refractive index of 1.4, as compared to without silicon coating due to the enhanced energy coupling between plasmon and core modes. The increased silicon thickness improves the sensitivity factor to 4000nm/RIU.