Display omitted
Functionalized graphene oxide is a novel type of highly efficient biosensing material. In this study, we present a carboxyl-functionalized graphene oxide (GO-COOH)-based surface ...plasmon resonance (SPR) chip for the rapid and quantitative detection of non-small cell lung carcinoma (NSCLC) via the cytolerayin 19 (CK19) protein biomarker in spiked human plasma. We demonstrated the binding specificity of kinetic analysis of interactions between GO-COOH and anti-CK19 and CK19 protein. We also calculated the relationship between the SPR angle and refractive index of GO-COOH, and demonstrated that COOH modified GO sheets on Au film can enhance the field energy propagation intensity of an SPR sensor, resulting in a higher sensitivity for the detection of CK19 protein compared to a conventional Au-based SPR chip. The immunosensor was constructed and engineered by immobilizing a low concentration (10 μg/mL) of CK19 antibody on an SPR chip. The lowest detectable concentration was as low as 1 fg/mL. A spiked 10% human plasma CK19 detection limit of 0.05 pg/mL was achieved, well below the normal physiological level of serum protein (3.3 ng/mL). Therefore, a carboxyl-GO based SPR biosensor appears to have high sensitivity and specificity for the detection of clinical whole plasma biomarkers and possible application in diagnosing diseases.
The surface plasmon resonance (SPR) biosensor has become a powerful analytical tool for investigating biomolecular interactions. There are several methods to excite surface plasmon, such as coupling ...with prisms, fiber optics, grating, nanoparticles, etc. The challenge in developing this type of biosensor is to increase its sensitivity. In relation to this, graphene is one of the materials that is widely studied because of its unique properties. In several studies, this material has been proven theoretically and experimentally to increase the sensitivity of SPR. This paper discusses the current development of a graphene-based SPR biosensor for various excitation methods. The discussion begins with a discussion regarding the properties of graphene in general and its use in biosensors. Simulation and experimental results of several excitation methods are presented. Furthermore, the discussion regarding the SPR biosensor is expanded by providing a review regarding graphene-based Surface-Enhanced Raman Scattering (SERS) biosensor to provide an overview of the development of materials in the biosensor in the future.
The most commonly used protein detection methods in clinical diagnosis and disease monitoring are enzyme-linked immunosorbent assay (ELISA), Western blotting (immunoblot), and lateral flow assay ...(LFA) rapid screening, of which ELISA is the gold standard immunoassay in clinical practice ...
Gold nanoparticles (AuNPs) have been widely used for various applications because of their unique properties. In this study, theoretical and experimental studies have been carried out to study the ...signal characteristics of the AuNPs-based localized surface plasmon resonance (LSPR) immunosensor. The finite-difference time domain (FDTD) method has been chosen to obtain information regarding optical properties and electric field profiles of AuNPs with different structures and configurations. The simulation results show that the distance between particles greatly affects the extinction and scattering spectra. In addition, there was a significant enhancement in the electric field due to the presence of dielectric material on the surface of AuNPs. In the case of dimer nanoparticles, the enhancement of the electric field is up to 20 times higher than that of single AuNPs. Experimentally, the enhancement of the electric field causes the detection range of the sensor to be limited. From the different concentrations of bovine serum albumin (BSA) investigated, the sensor is only able to detect BSA from 1 ng/mL to <inline-formula> <tex-math notation="LaTeX">10 \mu \text{g} </tex-math></inline-formula>/mL. We encountered the Hook effect in this experiment which was characterized by a decrease in the LSPR signal at a concentration of <inline-formula> <tex-math notation="LaTeX">100 \mu \text{g} </tex-math></inline-formula>/mL. A thicker dielectric layer can enhance the electric field around the nanoparticles and as a result, interference from changes in refractive index (RI) originating from other materials around the nanoparticles becomes difficult to avoid.
This work demonstrates the excellent potential of carboxyl-functionalized graphene oxide (GO–COOH) composites to form biocompatible surfaces on sensing films for use in surface plasmon resonance ...(SPR)-based immunoaffinity biosensors. Carboxyl-functionalization of graphene carbon can modulate its visible spectrum, and can therefore be used to improve and control the plasmonic coupling mechanism. The binding properties of the molecules between a sensing film and a protein were elucidated at various flow rates of those molecules. The bio-specific binding interaction among the molecules was investigated by performing an antigen and antibody affinity immunoassay. The results thus obtained revealed that the overall affinity binding value, KA, of the Au/GO–COOH chip can be significantly enhanced by up to ∼5.15 times that of the Au/GO chip. With respect to the shifts of the SPR angles of the chips, the affinity immunoassay interaction at a BSA concentration of 1μg/ml for an Au/GO-COOH chip, an Au/GO chip and a traditional SPR chip are 35.5m°, 9.128m° and 8.816m°, respectively. The enhancement of the antigen-antibody interaction of the Au/GO–COOH chip cause this chip to become four times as sensitive to the SPR angle shift and to have the lowest antibody detection limit of 0.01pg/ml. These results indicate the potential of the chip in detecting specific proteins, and the development of real-time in vivo blood analysis and diagnosis based on cancer tumor markers.
•Covalently linked biocompatible GO–COOH composites are utilized in SPR-based immunoaffinity biosensors.•The affinity binding value of the Au/GO–COOH chip was up to ~5.15 times that of the Au/GO chip.•The detection limit of the Au/GO–COOH chip is 0.01pg/ml, with a correlation coefficient of 0.973 at linear range of 0.01–100pg/ml.
The use of functionalized graphene oxide (fGO) has led to a new trend in the sensor field, owing to its high sensitivity with regards to sensing characteristics and easy synthesis procedures.
In this ...study, we developed an ultra-sensitive carboxyl-graphene oxide (carboxyl-GO)-based surface plasmon resonance (SPR) aptasensor using peptides to detect human chorionic gonadotropin (hCG) in clinical serum samples. The carboxyl-GO based SPR aptasensor provided high affinity and stronger binding of peptides, which are great importance to allow for a non-immunological label-free mechanism. Also, it allows the detection of low concentrations of hCG, which are in turn considered to be important clinical parameters to diagnose ectopic pregnancies and paraneoplastic syndromes.
The high selectivity of the carboxyl-GO-based SPR aptasensor for hCG recombinant protein was verified by the addition of the interfering proteins bovine serum albumin (BSA) and human serum albumin (HSA), which did not affect the sensitivity of the sensor. The carboxyl-GO-based chip can enhance the assay efficacy of interactions between peptides and had a high affinity binding for a k
of 17×10
M
S
. The limit of detection for hCG in clinical serum samples was 1.15 pg/mL.
The results of this study demonstrated that the carboxyl-GO-based SPR aptasensor had excellent sensitivity, affinity and selectivity, and thus the potential to be used as disease-related biomarker assay to allow for an early diagnosis, and possibly a new area in the field of biochemical sensing technology.
We constructed a novel surface plasmon resonance (SPR) detection assay using carboxyl-functionalized molybdenum disulfide (carboxyl-MoS2) nanocomposites as a signal amplification sensing film for the ...ultrasensitive detection of the lung cancer-associated biomarker cytokeratin 19 fragment (CYFRA21-1). The experiment succeeded in MoS2 reacted with chloroacetic acid giving carboxyl-MoS2 as the reaction product. The additional shoulder in the C 1s and O 1s peaks of carboxyl-MoS2, which were increased in X-ray photoelectron spectroscopy, confirmed the presence of O-C=O groups on the surface of the carboxyl-MoS2. Compared to MoS2, the experimental results confirmed that carboxyl-modified MoS2 had improved low impedance and low refractive index. The carboxyl-MoS2-based chip had a high affinity, with an SPR angle shift enhanced by 2.6-fold and affinity binding K A enhanced by 15-fold compared to a traditional SPR sensor. The results revealed that the carboxyl-MoS2-based chip had high sensitivity, specificity, and SPR signal affinity, while the CYFRA21-1 assay in spiked clinical serum showed a lower detection limit of 0.05 pg/mL and a wider quantitation range (0.05 pg/mL to 100 ng/mL). The carboxyl-MoS2-based chip detection value was about 104 times more sensitive than the limit of detection of an enzyme-linked immunosorbent assay (ELISA) (0.60 ng/mL). The results showed that the carboxyl-MoS2-based chip had the potential to rapidly assay complex samples including bodily fluids, whole blood, serum, plasma, urine, and saliva in SPR-based immunosensors to diagnose diseases including cancer.
Specific peptide aptamers can be used in place of expensive antibody proteins, and they are gaining increasing importance as sensing probes due to their potential in the development of ...non-immunological assays with high sensitivity, affinity and specificity for human chorionic gonadotropin (hCG) protein. We combined graphene oxide (GO) sheets with a specific peptide aptamer to create a novel, simple and label-free tool to detect abnormalities at an early stage of pregnancy, a GO-peptide-based surface plasmon resonance (SPR) biosensor. This is the first binding interface experiment to successfully demonstrate binding specificity in kinetic analysis biomechanics in peptide aptamers and GO sheets. In addition to the improved affinity offered by the high compatibility with the target hCG protein, the major advantage of GO-peptide-based SPR sensors was their reduced nonspecific adsorption and enhanced sensitivity. The calculation of total electric field intensity (ΔE) in the GO-based sensing interfaces was significantly enhanced by up to 1.2 times that of a conventional SPR chip. The GO-peptide-based chip (1mM) had a high affinity (KA) of 6.37×1012M−1, limit of detection of 0.065nM and ultra-high sensitivity of 16 times that of a conventional SPR chip. The sensitivity of the slope ratio of the low concentration hCG protein assay in linear regression analysis was GO-peptide (1mM): GO-peptide (0.1mM): conventional chip (8-mercaptooctanoic acid)-peptide (0.1mM)=8.6: 3.3: 1. In summary, the excellent binding affinity, low detection limit, high sensitivity, good stability and specificity suggest the potential of this GO-peptide-based SPR chip detection method in clinical application. The development of real-time whole blood analytic and diagnostic tools to detect abnormalities at an early stage of pregnancy is a promising technique for future clinical application.
•We demonstrate the design of a novel graphene oxide (GO)-peptide-based SPR biosensor.•The GO-peptide-based chip had a high affinity of 6.37×1012M−1, LOD of 0.065nM and ultra-high sensitivity of 16 times that of a conventional SPR chip.•The high specificity and biostability of the GO film to the peptide increased affinity binding by up to 5.24 times.•The sensitivity of the slope ratio of low concentrations of hCG protein in linear regression analysis was GO-peptide: conventional chip=8.6: 1.
Until now, Surface Plasmon Resonance (SPR) biosensors still rely on gold as their transducer element, and this makes cheap analytical devices difficult to achieve. On the other hand, lossy mode ...resonance (LMR) sensors offer transducers with more alternative materials due to their flexibility, which can be excited in p‐ and s‐polarized light. In this research it is carried out a numerical investigation using the transfer matrix method on LMR sensor composed of molybdenum disulfide (MoS2) as lossy layer and Cytop as matching layer. The reflectance curves for different thicknesses of MoS2 and Cytop are numerically investigated. The results obtained show that the chip consisting of 250 nm Cytop and 4 layers of MoS2 has a penetration depth 3 times higher than conventional SPR chips. If sensors with two types of polarization are compared, sensors with s‐polarized light have shown higher sensitivity reaching 72.13°/RIU with a wider dynamic range starting from a refractive index of 1.331 to 1.401. In this refractive index range, this sensor has displayed good signal stability where the reduction in resonance dip depth is only ≈6%. These computational results make the proposed structure very promising to be applied in the quantification of biological materials.
LMR sensor become alternative sensors that can replace SPR biosensors. Through a computational approach, obtaining an LMR sensor is succeeded with better sensitivity reaching 72.13°/RIU and wider detection range ranging from 1.331 to 1.401. In this refractive index range, the sensor shows excellent signal stability where the reduction in resonance dip depth is only ≈$ \approx $6%.
PDF
