Detection Of C-reactive Protein Research Articles

Fabrication and evaluation of optical nanobiosensor based on localized surface plasmon resonance (LSPR) of gold nanorod for detection of CRP

C-reactive protein (CRP) is a plasma protein that is one of the most expressed proteins in acute phase inflammation cases. It is a well-known biomarker for inflammatory disorders. There is a significant correlation between increasing CRP concentration and the risk of being exposed to cardiovascular diseases (CVD) and sepsis; thus, monitoring and quantifying CRP levels in a simple, inexpensive, and quick manner can improve clinical diagnostics and help prevent major inflammatory conditions. Here a nanobiosensor was developed, benefiting from the LSPR property of gold-nanorod (GNR) to measure CRP concentration. Nanorods were fabricated using One-pot synthesis by trimethyl ammonium bromide (CTAB) as a surfactant. This method provides the advantage of both step and time reduction in synthesis and decreases the contamination probability of nanorods as the products. The nanorods were characterized using TEM with an average size of (24 ± 1 nm) × (5 ± 1 nm) and a typical aspect ratio of ∼4.9. The surface of the rods was modified with a specific aptamer for the target protein, and the LSPR shifts due to the gold nanorod's refractive index change as the result of protein interaction with the biosensor investigated using a 100–900 nm UV absorption device. The results indicated that the nanobiosensor could respond to different CRP concentrations within 30 min. The selectivity test has shown nonresponsive results of nanobiosensor to BSA and TNF-α proteins which are used to evaluate the biosensor behavior in non-target proteins. The detection limit was evaluated at 2 nM, and the sensor's linear response ranged between 2 - 20 nM.

Ultrasensitive Detection of C-Reactive Protein by a Novel Nanoplasmonic Immunoturbidimetry Assay.

Nanotechnology has attracted much attention, and may become the key to a whole new world in the fields of food, agriculture, building materials, machinery, medicine, and electrical engineering, because of its unique physical and chemical properties, including high surface area and outstanding electrical and optical properties. The bottom-up approach in nanofabrication involves the growth of particles, and we were inspired to propose a novel nanoplasmonic method to detect the formation of nanoparticles in real time. This innovative idea may contribute to the promotion of nanotechnology development. An increase in nanometer particle size leads to optical extinction or density (OD)-value changes in our nanosensor chip at a specific wavelength measured in a generic microplate reader. Moreover, in applying this method, an ultrasensitive nanoplasmonic immunoturbidimetry assay (NanoPITA) was carried out for the high-throughput quantification of hypersensitive C-reactive protein (CRP), a well-known biomarker of cardiovascular, inflammatory, and tumor diseases. The one-step detection of the CRP concentration was completed in 10 min with high fidelity, using the endpoint analysis method. The new NanoPITA method not only produced a linear range from 1 ng/mL to 500 ng/mL CRP with the detection limit reduced to 0.54 ng/mL, which was an improvement of over 1000 times, with respect to regular immunoturbidity measurement, but was also effective in blood detection. This attractive method, combined with surface plasmon resonance and immunoturbidimetry, may become a new technology platform in the application of biological detection.

Ultrasensitive aptamer-functionalized Cu-MOF fluorescent nanozyme as an optical biosensor for detection of C-reactive protein

In the present work, an aptasensing method based on integration of RNA on Cu-MOF was developed for detection of C-Reactive Protein (CRP). Cu-MOF showed stimulated fluorescence and mimetic peroxidase enzymatic activity at the time and can be used as dual-signal transduction. CRP binding RNA was used as a highly selective recognition element and immobilized on the Cu-MOF. The immobilized RNA can block the peroxidase activity and fluorescence of the signal traducer probe. Adding CRP to the RNA/Cu-MOF will release RNA from the surface of Cu-MOF and recover both the stimulated fluorescence and peroxidase activity. A biosensor was built for detection of CRP using the two modes of transduction, either colorimetry or fluorometry. A dynamic linear range was obtained from 0.1 to 50 ng mL −1with a limit of detection (LOD) as small as 40 pg mL −1was calculated in fluorescence mode and 240 pg mL −1 as LOD in colorimetry mode. The LODs are lower than the LOD of nephelometric techniques used in clinical practice and is comparable to the normal clinical cutoff value in high-sensitivity CRP assays (1 μg/mL). The aptasensor was successfully applied for detection of CRP in Covid-19 patients with spike recoveries between 84 and 102% and RSD from 0.94% to 2.05%.

On-Chip Self-Referenced Micro-Resonators Enhanced by Digital Optical Frequency Comb for Ultra-Sensitive C-Reactive Protein Detection

An on-chip self-referenced transducer assisted by digital optical frequency comb (DOFC) technology is presented for the biomolecules detection in the lower detecting limit. This self-referenced stricture eliminates temperature cross sensitivity between the detecting and reference micro-resonators fabricated on the chalcogenide glass platform. The high-resolution DOFC technology has the ultra-fine-comb spacers offering for visualized spectral analysis of micro-resonators and capturing the subtle changes of ultra-low concentrations. Combining the self-referenced and DOFC technology, the detection of C-reactive protein in the concentration from 0.1 ng/mL to 500 ng/mL with the theoretically limit of detection of 0.0146 ng/mL is achieved. Given its small footprint, compactness and high analytical performances, the proposed transducing platform has the potential for applications on integration and minimization sensing on a single integrated chip.

The Predictive Values of MMP-9, PLTs, ESR, and CRP Levels in Kawasaki Disease with Cardiovascular Injury.

Objective To explore the levels of matrix metalloproteinase-9 (MMP-9), platelets (PLTs), C reactive protein (CRP), and erythrocyte sedimentation rate (ESR) and their predictive values in Kawasaki disease (KD) with cardiovascular injury. Methods 128 children were diagnosed with KD in the Lanzhou University Second Hospital. 75 patients had coronary artery lesion (CAL), while 53 patients did not. The levels of MMP-9, PLTs, and CRP and ESR in the two groups were determined. The area under the curve (AUC) of the receiver-operating characteristic (ROC) curve and the Youden index (YI) were used to evaluate the efficacy of MMP-9, PLTs, ESR, and CRP for predicting CALs in KD. Results The mean age of the patients was 2.7 ± 2.03 years (range, 2 months to 11 years). There were 87 boys (67.97%) and 41 girls (32.03%). In contrast to the NCAL group, the CAL group had obviously higher levels of MMP-9, PLTs, and CRP and an obviously higher ESR (P < 0.05). MMP-9 showed a linear positive correlation with ESR (P < 0.05) and CRP (P < 0.05). The AUC of the combined detection of the four indicators was 0.877, the sensitivity was 85.07% and the specificity was 78.95%. Conclusion MMP-9, PLTs, ESR, and CRP are important indicators for a CAL in KD. The efficacy of the combined detection of MMP-9, PLTs, ESR and CRP is better than that of any single indicator for predicting a CAL in KD.

Self-assembly strategy to reduce non-specific adsorption for the development of high sensitivity quantitative immunoassay

The development of functionalized surfaces with low non-specific adsorption is important for their biomedical applications. To inhibit non-specific adsorption on glass substrate, we designed a novel optical biochip by modifying a layer of dense negatively charged film (SO32−) on its substrate surface via self-assembly. Compared with the untreated glass substrate, it reduced the adsorption by about 300-fold or 400-fold by poly (styrene sulfonic acid) sodium salt (PSS), or meso-tetra (4-sulfonatophenyl) porphine dihydrochloride (TSPP) on individually the modified glass substrate. Considering the effect of fluorescence resonance energy transfer (FRET) between TSPP and the QDs in solution by mixing, a strategy of 2-layer of TSPP followed by 4-layer of PSS was designed to modify the glass for preparing biochips. Under the optimized conditions, the biochip on functionalized glass substrate co-treated with TSPP and PSS realized the sensitive quantitative detection of C-reactive protein (CRP) based on a quantum dot fluorescence immunosorbent assay (QD-FLISA). The limit of detection (LOD) for CRP achieved 0.69 ng/mL with the range of 1-1,000 ng/mL using TSPP and PSS co-treated glass substrate surface, which was respectively about 1.9-fold and 7.5-fold more sensitive to the PSS-modified biochip and the TSPP-modified biochip. This work demonstrated an effective and convenient strategy to obtain biochips with low non-specific adsorption properties on functionalized surfaces, thus providing a new approach for creating ultra-high sensitivity microchannels or microarrays on glass substrates.

Comparison of direct and sandwich type immunoassays on electrospun nanofibers using of metal organic frameworks as a fluorescence probe

Here, colloidal fluorescent Fe (III) metal organic frameworks (FeMOFs) were synthesized using FeCl3 as Fe3+ ion source and lactose 1-aminonaphthalene (L1AN) as an organic linker by one-step synthesis approach. C-reactive protein antibody (Anti-CRP) was conjugated to L1AN-FeMOF through amide bond formation, which was then applied to the detection of C-reactive protein (CRP) using sandwich-type and immunometric assays. To cover 96-well plate surfaces, polycaprolactone and poly (amic acid) (PCL/PAA) electrospun nanofibers were synthesized. Limit of detection (LOD) for CRP was obtained as 4.8 pg/mL for the sandwich assay and 9.0 pg/mL for the immunometric assay in buffer systems using high throughput sensing approach. Real sample applications in artificial saliva and simulated serum validated the reliability of the approach. Selectivity control tests were performed using common serum-based interferents, for which minimum to no interference was observed. Based on the findings, the developed assay can be offered as a new approach in the detection of CRP in clinical samples.

Magnetic Nanoparticles Detection of C-Reactive Protein Combined with Neutrophil to Lymphocyte Ratio to Predict the Occurrence of Anastomotic Fistula after Rectal Cancer Surgery.

It aimed to explore the effect of C-reactive protein (CRP) combined with neutrophil to lymphocyte ratio (NLR) in the early prediction of anastomotic leakage (AL) after rectal cancer surgery and to improve the prediction accuracy. In this study, gold (Au)/ferroferric oxide (Fe3O4) magnetic nanoparticles were first synthesized and modified with polyacrylic acid (PAA). After modification, they underwent CRP antibody detection. Then, 120 patients with rectal cancer who underwent Dixon surgery were selected as the research objects to investigate the sensitivity and specificity of CRP combined with NLR in predicting AL. It was found that the diameter of the Au/Fe3O4 nanoparticles prepared in this study was about 45 nm. After adding 60 μg of antibody, the diameter of PAA-Au/Fe3O4 was 226.5 nm, the dispersion coefficient was 0.16, the standard curve between CRP concentration and luminous intensity was y = 8,966.5 x + 2,381.3, and R2 = 0.9944. Besides, the correlation coefficient was R2 = 0.991, and the linear regression equation was y=1.103 x - 0.0022 compared with the nephelometric method. By analyzing the receiver operating characteristic (ROC) curve of CRP combined with NLR to predict AL after Dixon surgery, the cut-off point was 0.11 on the first day after the surgery, the area under the curve was 0.896, the sensitivity was 82.5%, and the specificity was 76.67%. The cut-off point on the third day after the surgery was 0.13, the area under the curve was 0.931, the sensitivity was 86.67%, and the specificity was 90%. On the fifth day after the surgery, the cut-off point, the area under the curve, the sensitivity, and the specificity were 0.16, 0.964, 92.5%, and 95.83% in turn. In conclusion, PAA-Au/Fe3O4 magnetic nanoparticles could be used for clinical examination of patients with rectal cancer, and CRP combined with NLR could improve the prediction accuracy of AL after rectal cancer surgery.

Improving the fluorescence intensity of lanthanide-doped microspheres via incorporation of lauryl methacrylate: Synthesis and their application in C-reactive protein detection

Lanthanide-doped microspheres, especially europium complexes, are widely utilized as fluorescent reporters in lateral flow immunoassays. High fluorescence signal output, which is closely associated with the synthesis of microsphere, is critical for this procedure. Here, the interior structure of microspheres was attempted to be adjusted by introducing plasticizer lauryl methacrylate (LMA) into the polymerization of styrene monomer to improve the amount of europium complexes encapsulated in microspheres. The scanning electron microscope (SEM) results showed that the microspheres containing LMA were spherical and uniform in size (the average size 291 nm). A maximal fluorescence signal was reached when the microspheres were prepared by adding 10 wt% LMA relatively to styrene, which is almost three times that of microspheres without LMA. Such elevation in fluorescence signal can be attributed to the increment in content of encapsulated europium complexes (about 47.10 mg/g, which is far higher than other reported methods (3.72 or 1.023 mg/g)) induced by reducing the regularity of the polymer chain and increasing its flexibility as well as distensibility inside microspheres with LMA. Thanks to such superior fluorescence property, lateral flow immunoassay was successfully founded to detect C-reactive protein (CRP) with a linear response in concentration range of 1.3–210.7 μg/L. Therefore, the fundamental advance in this work is to provide the way to adjust the environment inside microspheres for encapsulation of europium complexes, which lays a good foundation for preparing microsphere with high fluorescence intensity.

Mesoporous platinum nanoparticles as a peroxidase mimic for the highly sensitive determination of C-reactive protein.

The generation of a mesoporous structure in platinum nanoparticles can effectively enhance physical and chemical properties. In this study, mesoporous platinum nanoparticles (MPNs) were synthesized by a soft template-mediated one-pot chemical method. To develop a mesoporous structure, Pluronic F-127 was employed. The Pluronic F-127 surfactant forms self-assembled micelles, and the micelles act as the pore-directing agents in the synthesis of nanoparticles. Scanning electron microscopy results revealed that the MPN had a uniform size of 70nm on average and a distinct mesoporous structure. The development of a concave mesoporous structure on the surface of the MPNs can increase the surface area and facilitate the efficient transport of reactants. The synthesized MPNs exhibited peroxidase-like activity. Furthermore, the MPNs showed excellent catalytic efficiency compared to HRP, due to the high surface area derived from the presence of the mesoporous structure. The peroxidase-like MPNs were applied to the enzyme-linked immunosorbent assay (ELISA) of C-reactive protein (CRP). The MPN-based ELISA exhibited sensitive CRP detection in the range from 0.24 to 7.8ng/mL with a detection limit of 0.13ng/mL. Moreover, the recoveries of the CRP concentrations in spiked human serum were 98.6% and 102%. These results demonstrate that as a peroxidase mimic, the MPNs can replace the natural enzymes in conventional ELISA for sensitive CRP detection.

Diagnostic Value of Color Doppler Flow Imaging Combined with Serum CRP, PCT, and IL-6 Levels for Neonatal Pneumonia.

Objective To evaluate the diagnostic value of combined detection of color Doppler flow imaging (CDFI) and serum C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6) levels for neonatal pneumonia. Methods In this prospective study, 30 newborns with pneumonia and 30 healthy newborns in our hospital from January 2019 to January 2020 were recruited. The healthy newborns were assigned to the control group, and the newborns with pneumonia were assigned to the experimental group. All subjects underwent CDFI and measurement of the levels of serum CRP, PCT, and IL-6. The serum indices and imaging results of the two groups were analyzed, and the specificity and sensitivity of different detection methods in the diagnosis of neonatal pneumonia were calculated and analyzed. Results The levels of serum CRP, PCT, and IL-6 in the experimental group were significantly higher than those in the control group (P < 0.001). Combined detection had a larger detection area, higher sensitivity, and a superior overall detection outcome than single detection (P < 0.05). The diagnostic results of combined detection and clinical diagnosis in 30 newborns with pneumonia were similar (P > 0.05). Conclusion The combined detection of CDFI and serum CRP, PCT, and IL-6 levels in the diagnosis of neonatal pneumonia shows a promising diagnostic outcome, so it is worthy of clinical application.

Chemiresistive CuO sensors for label-free C-reactive protein detection

In this study, we developed fast and highly sensitive, label-free Ca-doped cupric oxide (CuO) based chemiresistive biosensors to detect C-reactive protein (CRP). The Successive Ionic Layer Adsorption and Reaction (SILAR) method was used to deposit pure and Ca-doped CuO thin films on interdigitated gold electrodes. Film surfaces were functionalized with monoclonal anti-C-reactive protein antibody (anti-CRP) by random physisorption method. Sensor fabrication steps were monitored using the linear sweep voltammetry method. Scanning electron microscopy was used to investigate the surface morphology. Energy-dispersive X-ray spectroscopy was used to determine the elemental composition. The structure of the films was investigated by the powder X-ray diffractometry method. Sensor parameters were determined by the change in sensor resistance over time. The sensors showed a good response to CRP with a linear detection range of 0.1–5.0 µg/ml, which was within the clinically significant range. Detection limits of 49.61 and 48.81 ng/ml were estimated using the standard deviation of the y-intercept and the standard deviation of the regression line, respectively. Dynamic response times of all fabricated sensors were found to be less than 30 s

Electrochemical aptasensor based on anisotropically modified (Janus-type) gold nanoparticles for determination of C-reactive protein.

Novel Janus nanoparticles based on Au colloids anisotropically modified with polyamidoamine dendrons were prepared though a masking/toposelective modification approach. These nanomaterials were further functionalized with horseradish peroxidase on the dendritic face and provided on the opposite metal surface with a ssDNA aptamer for C-reactive protein (CRP). The resulting nanoparticles were employed asbiorecognition/signaling elements to construct an amperometric aptasensor with sandwich-type architecture for the specific detection of this cardiac biomarker. To do this, screen-printed carbon electrodes modified with electrodeposited Au nanoparticles and functionalized with anti-CRP aptamers were used as transduction interface. The aptasensor was employed for the amperometric detection of CRP (working potential: - 200mV vs pseudo-Ag/AgCl) in the broad range from 10pg·mL-1 to 1.0ng·mL-1 with a detection limit of 3.1pg·mL-1. This electroanalytical device also showed good specificity, reproducibility (RSD = 9.8%, n = 10), and stability and was useful to quantify CRP in reconstituted human serum samples, with a RSD of 13.3%.

Label-free dynamic light scattering assay for C-reactive protein detection using magnetic nanoparticles

In this work, we present a simple method for label-free detection of C-reactive protein (CRP) in diluted saliva samples without the use of specific molecules against CRP. We use the dynamic light scattering (DLS) technique and silica-coated Fe3O4 nanoparticles (∼50 nm in diameter) functionalized with amino carboxylate moieties (Fe3O4@SiO2/COOH) as probes. After contact with the sample, the particles could be easily separated with a handy magnet and redispersed for DLS analysis simply by vortex shaking. The variation of the hydrodynamic diameter of the nanoparticles (Z-average size) could be correlated with the concentration of CRP up to concentrations of 10 mg L−1. The detection limit (LOD) in diluted saliva samples that were spiked with CRP was 0.205 mg L−1, which is below salivary levels of CRP detected in unhealthy individuals. The coefficient of variation was found to be less than 1.5% in the entire detection range. The variation of Z-average size of non-functionalized silica coated nanoparticles (Fe3O4@SiO2) also correlated well with CRP concentration. Nevertheless, the Fe3O4@SiO2/COOH nanoparticles were less susceptible to interference from other biomolecules present in saliva and adsorbed more CRP, indicating higher selectivity toward CRP than nonfunctionalized nanoparticles. This higher affinity was attributed to the chelating interaction between the aminocarboxylate groups of the organosilane N-[3-(trimethoxysilyl)propyl]ethylenediaminetriacetic acid trisodium salt (EDTA-TMS) grafted onto the surface of the Fe3O4@SiO2/COOH nanoparticles and the Ca2+ ions of CRP. LC-MS/MS analyses allowed identification of the proteins adsorbed on the nanoparticles and confirmation of the presence of CRP, which is involved in several biological processes, including immune response, response to stress and transport.

Faradaic electrochemical impedimetric analysis on MoS2/Au-NPs decorated surface for C-reactive protein detection

BackgroundA label-free Faradaic electrochemical impedimetric was developed for a highly sensitive detection of C-reactive protein using a gold interdigitated microelectrode bio-sensing platform enhanced by a gold nanoparticle-decorated molybdenum disulfide (Au-NPs/MoS2) nanosheet via selected chemical linking processes. C-reactive protein (C-RP), a crystalline protein, generates by the liver and hikes when there is inflammation throughout the patients’ body. The concentrations of C-RP plasma levels tend to increase rapidly when the patient facing major injury which will lead to cardiovascular disease (CVD). MethodsThe 5 µm microelectrode and gap size g-IDE with the nanostructured materials was demonstrated to increase the impedimetric detection response in Faradaic-mode electrochemical impedance spectroscopy high performance detection environment. The high surface area-to-volume ratio of the modified Au-NPs/MoS2 nanocomposite increased the probes loading onto the transducer and enhanced the impedimetric detection response of the C-RP target post-binding due to an amplified net change in the charge transfer resistance. The developed immunoassay revealed a linear detection of C-RP biomarker in a logarithmic-scale from as low as 1 fg/mL up to 1 µg/mL, and a limit of detection of 0.01 fg/mL. The sensor shows great potential as an early warning risk for cardiovascular disease at a threshold concentration value of C-RP at 1 µg/mL. Significant findingsThe biosensor demonstrates an excellent discrimination against other competing proteins in serum, exhibiting the highest predilection to C-RP spiked human serum target. The sensor's reproducibility is reported within an acceptable range of relative standard deviation of 1–4% for n = 3.

Value of combined detection of serum amyloid A, C-reactive protein and procalcitonin in differential diagnosis of respiratory tract infection in children of China

Objective To explore the diagnostic value of combined detection of serum amyloid A (SAA), C-reactive protein (CRP) and procalcitonin (PCT) in children with bacteria or non-bacterial respiratory tract infection. Methods 200 children with respiratory tract infections diagnosed in our hospital were included in the study. According to the results of the aetiological examination, they were divided into bacterial infection group and non-bacterial infection group. At the same time, 100 healthy children admitted to the hospital for physical examination during the same period were selected as the healthy subjects control group. Changes in serum SAA, PCT and CRP in three groups were compared. Comparison of a positive rate of the single index and combined detection were performed. Children with bacterial infections were treated with conventional antibiotics. The changes in serum SAA, PCT and CRP in the infection group before and after treatment were compared. The efficacy of SAA, PCT and CRP alone and in combination was compared. Results The serum SAA, PCT and CRP levels in the bacterial infection group were higher than those in the non-bacterial infection group and healthy children, and the differences were statistically significant. The positive detection rates and combined detection rates of serum SAA, PCT and CRP in the bacterial infection group were higher than those in the non-bacterial infection group and the healthy subject's control group. After conventional antibiotic treatment, serum SAA, PCT and CR levels in children with bacterial infection were significantly decreased. Conclusion The combined detection based on SAA, CRP and PCT can effectively identify and diagnose respiratory tract infection in children, providing a certain reference for the promotion of the diagnostic scheme. Key messages Serum SAA, PCT and CRP were highly expressed in children with respiratory tract infection, and the expression level was the highest in children with bacterial pneumonia. The combined detection of serum SAA, CRP and PCT indicators have higher diagnostic efficiency and can effectively make a differential diagnosis of respiratory tract infection in children.

Monitoring Mycoplasma pneumoniae-Specific Antibody, C-Reactive Protein, and Procalcitonin Levels in Children with Mycoplasma Pneumonia Is Important.

The goal of this study was to see how important it is to monitor Mycoplasma pneumoniae-specific antibody IgM, C-reactive protein, and procalcitonin levels in the blood of kids with Mycoplasma pneumoniae pneumonia as a reference for clinical diagnosis and treatment. The study group consisted of 96 children who had mycoplasma pneumonia in our hospital between May 2020 and May 2021, and the control group consisted of 96 healthy children who had a routine physical examination in our hospital at the same time. C-reactive protein and procalcitonin were measured and compared. The application value of single detection and combined detection of Mycoplasma pneumoniae-specific antibody IgM, C-reactive protein, and procalcitonin in the diagnosis of Mycoplasma pneumoniae pneumonia was evaluated based on clinical diagnosis results. The detection values of C-reactive protein and procalcitonin in the study group were higher than those in the recovery period and the control group, P < 0.05; the detection values of C-reactive protein and procalcitonin in the study group were higher than those in the control group, P < 0.05. The combination detection of Mycoplasma pneumoniae-specific antibody IgM, C-reactive protein, and procalcitonin had a greater diagnostic accuracy than single detection (P < 0.05). The sensitivity was higher than C-reactive protein and procalcitonin (P < 0.05); the specificity and positive predictive value were higher than Mycoplasma pneumoniae-specific antibody IgM (P < 0.05); and the negative predictive value was higher than procalcitonin (P < 0.05). The clinical value of combining the detection of Mycoplasma pneumoniae-specific antibody IgM, C-reactive protein, and procalcitonin in the diagnosis of Mycoplasma pneumoniae pneumonia in children is higher than that of single item detection, and it can provide a reliable clinical reference, as well as aid in evaluating the recovery effect of children, and it is worthy of application.

Analysis of Clinical Risk Assessment on the Detection of Procalcitonin, C-reactive Protein and D-dimer for Acute Pancreatitis

Analysis of Clinical Risk Assessment on the Detection of Procalcitonin, C-reactive Protein and D-dimer for Acute Pancreatitis

Label-free and highly sensitive detection of CRP based on the combination of nicking endonuclease-assisted signal amplification and capillary electrophoresis-UV assay

Elevated C-reactive protein (CRP) levels are linked with bacterial infection, local inflammation in osteoarthritis and the increased risk of developing cardiovascular disease. Here, a sensitive and label-free CRP assay is developed by combining cyclic enzymatic signal amplification and capillary electrophoresis (CE) with UV detection. This assay is constructed of base pairing and target recognition. Thereinto, nicking endonuclease (NEase) can recognize the specific nucleotide sequences in double-stranded DNA (dsDNA), which is formed by a CRP aptamer and its complementary DNA (cDNA). Sequentially, NEase cleaves only cDNA to produce signal DNAs. Therefore, a large number of signal DNAs are generated through continuous enzyme cleavage. In the presence of CRP, the aptamer recognizes and binds to CRP with high affinity and selectivity, which results in a decrease in signal DNAs, and thus the UV absorption value of CE significantly decreases, too. A wide linear range was obtained between 0.0125 and 15 μg mL−1 (0.11–130.5 nM) in 1% human serum with a detection limit of 4 ng mL−1 (35 pM). Additionally, the proposed method is universal and can be applied to analyze other similar substances by altering the matched aptamer.

A rapid fluorescent aptasensor for point-of-care detection of C-reactive protein

In this paper, we report on a novel fluorescent aptasensor based on aptamers modified by both nitrogen-doped graphene quantum dots (N-GQDs) and gold nanoparticles (AuNPs) for the detection of C-reactive protein (CRP). FRET effect is utilized in our aptasensor by the change of aptamers conformation when binding with the target. An obvious fluorescence quench of the N-GQDs can be observed when CRP appears in the assay due to electron transfer between the donor and accepter. A detection limit of 0.2 ng/mL can be achieved by our sensor in PBS buffer which is much lower than the physiological CRP level in human serum. Also, CRP levels in different patients’ serum are tested with our assay. Since our aptasensor is rapid (detection time less than 40 min), one-step and very simple to operate, we believe it has great potential to apply for point-of-care testing (POCT).