C-reactive Protein In Human Serum Research Articles

A Versatile Method to Create Antibody/Split‐Enzyme Complexes and Its Application to a Rapid, Homogeneous, and Universal Electrochemical Immunosensing System

AbstractIn this study, a versatile method is developed to create an antibody/split‐enzyme complex for use in electrochemical immunosensors. SpyCatchers are genetically fused at each terminus of flavin adenine dinucleotide‐dependent glucose dehydrogenase (FAD‐GDH) and a protease recognition sequence is inserted into a loop region to prepare a soluble protein and the split GDH. SpyTag‐fused single‐chain variable fragments (scFvs) are employed, which leads to the simple preparation of antibody‐split enzyme complexes (split AECs). The addition of pentameric C‐reactive protein (CRP), as a representative multimeric protein, restored the GDH activity of the split AECs, as the two split AEC fragments formed active GDH when in close proximity. CRP in human serum is electrochemically detected within 5 min without any washing steps with a clinically relevant CRP detection range (0.03–1 mg dL−1). The detection system is expanded to detect hemoglobin, SARS‐CoV‐2 spike protein, and inactivated SARS‐CoV‐2 by exchanging the scFvs. These results show that the convenient preparation method of the split GDH and the split AEC by the insertion of the protease recognition sequence and the use of SpyCatcher/SpyTag can realize a rapid, homogeneous, and universal electrochemical detection system that can be integrated into a commercially available electrochemical glucose sensor.

Multiplex signal amplification for ultrasensitive CRP assay via integrated electrochemical biosensor array using MOF-derived carbon material and aptamers

Accurate and precise detection of disease-associated proteins, such as C-reactive protein (CRP), remains a challenge in biosensor development. Herein, we present a novel approach－an integrated disposable aptasensor array－designed for precise, ultra-sensitive, and parallel detection of CRP in plasma samples. This integrated biosensing array platform enables multiplex parallel testing, ensuring the accuracy and reliability in sample analysis. The ultra-sensitivity of this biosensor is achieved through multiplex signal amplification. Leveraging the superior conductivity and extensive surface area of MOF-derived nanoporous carbon material (CMOF), the biosensor enhances recognition elements (aptamers) by catalyzing the horseradish peroxidase (HRP) label enzyme reaction to multiply the number of probe molecules. Optimized conditions yielded exceptional performance, exhibiting high accuracy (relative standard deviation, RSD≤10.0 %), a low detection limit (0.3 pg/mL, S/N = 3), ultra-sensitivity (0.16 μA/ng mL−1 mm−2), and a rapid response (seven parallel tests within 60 min). Importantly, this multi-unit integrated disposable aptasensor array accurately quantified CRP in human serum, demonstrating comparable results to commercial enzyme–linked immunosorbent assay (ELISA). This technology showcases promise for detecting various biomarkers using a unified approach, presenting an appealing strategy for early disease diagnosis and biological analysis.

Development of a C-reactive protein quantification method based on flow rate measurement of an ink solution pushed out by oxygen gas generated by catalase reaction.

A novel determinationmethod for protein biomarkers based on on-chip flow rate measurement was developed using a microchip with organic photodiodes (OPDs). This quantitative method is based on the flow rate measurement of an ink solution pushed out by oxygen gas generated through catalase reaction. The amount of oxygen gas generated in the sample reservoir is dependent on the concentration of the analyte; therefore, the flow rate of the ink solution is also dependent on the concentration of the analyte. The concentration of the analyte can thus be estimated by measurement of the ink solution flow rate. The ink solution flow rate was estimated by measuring the migration time of the ink solution between two points using two OPDs placed below the microchannel. The principle of this method was demonstrated by the measurement of catalase using the microchip. In addition, the developed method was applied to the determination of C-reactive protein (CRP), a biomarker of inflammation, based on a catalase-linked immunosorbent assay (C-LISA). The limit of detection for CRP was 0.20µg/mL. The method was also applied to the determination of CRP in human serum, and the quantitative values obtained by this method were in excellent agreement with those obtained by the conventional enzyme-linked immunosorbent assay (ELISA) method. The developed method does not require a photodetector with high sensitivity and is thus capable of downsizing; therefore, this will be useful for on-site analyses such as point-of-care testing and field measurements.

Implementing metrological traceability of C-reactive protein measurements: consensus summary from the Joint Committee for Traceability in Laboratory Medicine Workshop.

The Joint Committee for Traceability in Laboratory Medicine (JCTLM) currently lists the secondary commutable certified reference material (CRM) ERM DA-474/IFCC (DA-474) "C-Reactive Protein in Human Serum" and two generic immunoassay-based method principles as the basis for implementing the metrological traceability of C-reactive protein (CRP) measurements by end-user measurement procedures used by medical laboratories. The current metrological traceability has produced well harmonized results for clinical samples among different end-user measurement procedures. New higher-order pure substance and secondary commutable CRMs have been nominated for listing by the JCTLM. However, the data supporting performance of these new candidate CRMs, including use of new mass spectrometry based candidate reference measurement procedures (RMPs), was not clear regarding the influence that introducing these new CRMs would have on the current well harmonized results achieved with the existing metrological traceability to DA-474. The clinically relevant CRP measurand in blood serum or plasma is a pentamer of identical subunits, which adds complexity to the application of higher-order CRMs and RMPs. The JCTLM convened a workshop in December 2022 to review the appropriate implementation of metrological traceability of CRP measurements. The workshop consensus was that the extent-of-equivalence data must include considerations about the impact of a new CRM when used for its intended purpose in the calibration hierarchies of existing end-user measuring systems; and that a new RMP must compare results with another existing well validated candidate RMP or with a globally available end-user measurement system.

Fabrication of a Disposable Electrochemical Immunosensor Based on Nanochannel Array Modified Electrodes and Gated Electrochemical Signals for Sensitive Determination of C-Reactive Protein.

Sensitive determination of C-reactive protein (CRP) is of great significance because it is an early indicator of inflammation in cardiovascular disease and acute myocardial infarction. A disposable electrode with an integrated three-electrode system (working, reference, and counter electrodes) has great potential in the detection of biomarkers. In this work, an electrochemical immunosensing platform was fabricated on disposable and integrated screen-printed carbon electrode (SPCE) by introducing nanochannel arrays and gated electrochemical signals, which can achieve the sensitive detection of CRP in serum. To introduce active reactive groups for the fabrication of immuno-recognitive interface, vertically-ordered mesoporous silica-nanochannel film (VMSF) with rich amino groups (NH2-VMSF) was rapidly grown by electrochemical assisted self-assembly (EASA). The electrochemically reduced graphene oxide (ErGO) synthesized in situ during the growth of NH2-VMSF was used as a conductive adhesive glue to achieve stable bonding of the nanochannel array (NH2-VMSF/ErGO/SPCE). After the amino group on the outer surface of NH2-VMSF reacted with bifunctional glutaraldehyde (GA/NH2-VMSF/ErGO/SPCE), the converted aldehyde surface was applied for covalent immobilization of the recognitive antibody (Ab) followed with the blocking of the non-specific sites. The fabricated immunosensor, Ab/GA/NH2-VMSF/ErGO/SPCE, enables sensitive detection of CRP in the range from 10 pg/mL to 100 ng/mL with low limit of detection (LOD, 8 pg/mL, S/N = 3). The immunosensor possessed high selectivity and can realize reliable determination of CRP in human serum.

A diagnostic platform for rapid, simultaneous quantification of procalcitonin and C-reactive protein in human serum.

SummaryBackgroundEarly and accurate determination of bacterial infections as a potential cause for a patient's systemic inflammatory response is required for timely administration of appropriate treatment and antibiotic stewardship. Procalcitonin (PCT) and C-reactive protein (CRP) have both been used as biomarkers to infer bacterial infections, particularly in the context of sepsis. There is an urgent need to develop a platform for simultaneous quantification of PCT and CRP, to enable the potential use of these biomarkers at the point-of-care.MethodsA multiplexed lateral flow assay (LFA) and a fluorescence optical reader were developed. Assay performance was validated by testing spiked antigens in the buffer, followed by a validation study comparing results with conventional assays (Roche Cobas e411 Elecsys PCT and Siemens ADVIA XPT CRP) in 25 archived remnant human serum samples.FindingsA linear regression correlation of 0·97 (P < 0·01) was observed for PCT, and a correlation of 0·95 (P < 0·01) was observed for CRP using direct patient samples. We also validated our platform's ability to accurately quantify high-dose CRP in the hook effect range where excess unlabeled analytes occupy binding sites at test lines.InterpretationA fluorescence reader-based duplex LFA for simultaneous quantification of PCT and CRP was developed and successfully validated with clinical samples. The rapid, portable, and low-cost nature of the platform offers potential for differentiation of bacterial and viral infections in emergency and low-resource settings at the point-of-care.FundingNIH/NIBIB Award 1R01EB021331, and Academic Venture Fund from the Atkinson Center for a Sustainable Future at Cornell University.

Impact of surface roughness on the self-assembling of molecular films onto gold electrodes for label-free biosensing applications

The properties of molecular films assembled over gold electrode surfaces are prone to reflect fabrication characteristics. Here we show the importance of controlling electrode surface characteristics of a gold interface destined to label-free electrochemical biosensing applications and how to decrease the effect of the roughness on the properties of the interface by using redox composite materials within 5 to 10 nm in thickness. This controlling of surface characteristics allows us to fabricate reproducible, disposable printed circuit board microelectrodes for label-free electrochemical capacitive assays, which are specifically aimed at applications in point-of-care molecular diagnostic devices. We demonstrate that both the electrochemical roughness factor and the mechanical roughness root mean square of the surface are useful parameters for the quality control of molecularly assembled films and the chemical modification of the surface. For instance, the measured ionic capacitance of gold interfaces is linear as a function of an electrochemical roughness factor lower than ca. 2. On the other hand, roughness factor values higher than ca. 2 lead to a random ionic capacitance outcome. A similar trend of presenting reproducible or irreproducible electrochemical behavior, wherein a roughness threshold exists, is perceived for charge transfer resistance whether the interfacial redox activity is blocked with a dielectric molecular layer. It was also demonstrated that redox reversibility of gold interfaces is sensitive to the roughness root mean square. Finally, we also confirmed that if the roughness is controlled below a well-defined threshold or if a film thickness (within 5 to 10 nm) is assembled over the surface, the sensing properties are reproducible in micro-fabricated printed circuit board electrodes used in assaying C-reactive protein in human serum. This is an important upshot that permit the microfabrication of cost-effective microelectrodes for label-free electrochemical capacitive biosensors, within the capability to be further integrated into Lab-on-PCB microsystems.

A Diagnostic Platform for Rapid, Simultaneous Quantification of Procalcitonin and C-Reactive Protein in Human Serum

Background: Early and accurate determination of bacterial infections as a potential cause for a patient’s systemic inflammatory response is required for timely administration of appropriate treatment and antibiotic stewardship. Procalcitonin (PCT) and C-reactive protein (CRP) have both been used as biomarkers to differentiate bacterial infections from other causes in multiple studies, particularly in the context of sepsis. There is an urgent need to develop a platform for simultaneous quantification of PCT and CRP, to enable the potential use of these biomarkers at the point-of-care.: Methods: A multiplexed lateral flow assay (LFA) and a fluorescence optical reader were developed. Assay performance was validated by testing spiked antigens in the buffer, followed by a validation study comparing results with conventional assays (Roche Cobas e411 Elecsys PCT and Siemens ADVIA XPT CRP) in 25 archived remnant human serum samples. Findings: A correlation of 0·97 (P < 0·0001) was observed for PCT, and a correlation of 0·95 (P < 0·0001) was observed for CRP using direct patient samples. We also validated our platform’s ability to predict concentrations beyond the hook effect range for CRP accurately. Interpretation: A fluorescence reader-based duplex LFA for simultaneous quantification of PCT and CRP was developed and successfully validated with clinical samples. The rapid, portable, and low-cost nature of the platform offers potential for differentiation of bacterial and viral infections in emergency and low-resource settings at the point-of-care. Funding Information: NIH/NIBIB Award 1R01EB021331, and Academic Venture Fund from the Atkinson Center for a Sustainable Future at Cornell University. Declaration of Interests: The authors have no conflicts of interest to disclose related to this work. In the interest of full disclosure, David Erickson and Saurabh Mehta are founders and board members for a diagnostic start-up focused on measuring nutritional biomarkers at the point-of-care. Ethics Approval Statement: We acquired 25 remnant patient serum samples with known PCT and CRP concentrations from Weill Cornell Medicine (New York, NY, USA). These samples were approved for use by the Cornell Institutional Review Board (IRB 1706018345) used for assay validation.

Quantification of CRP in human serum using a handheld fluorescence detection system for capillary-based ELISA

We developed a handheld fluorescence detection system for capillary-based enzyme-linked immunosorbent assay (ELISA). The detection system implements both a long-pass filter and perpendicular optical arrangement, i.e., a power LED and a palm-sized spectrometer, to minimize background signals from the excitation light and optical scattering. The lower detection limit for resorufin was 0.13 μM. The detection system was applied to the quantification of C-reactive protein (CRP) in human serum with a capillary-based ELISA. The lower detection limit for CRP was 31 ng/ml, and the observed CRP levels in human serum were comparable to those obtained with a conventional ELISA system.

One-step non-competitive fluorescence polarization immunoassay based on a Fab fragment for C-reactive protein quantification

A non-competitive fluorescence polarization immunoassay (FPIA) using a Fab fragment was developed for large molecule quantification. Most conventional FPIAs are homogeneous and competitive immunoassays. With competitive FPIAs, it has been difficult to obtain sufficient detection sensitivity when targeting large molecules like proteins. To overcome this fundamental drawback, we report a non-competitive FPIA using a fluorescence-labeled Fab fragment. C-reactive protein (CRP) was used as model substance for validation of the Fab-based non-competitive FPIA. Quantitative analysis of CRP in phosphate buffered saline (PBS) was successfully achieved and the limit of detection (LOD) of CRP in PBS was 207 ng/mL. Moreover, using far-red emitting fluorescent dye (HiLyte Fluor™647) as a fluorescent labeling substance of Fab fragment, we measured CRP in human serum without pretreatment of a sample in 10 min around the cut-off value of CRP (10 μg/mL). The LOD of CRP in human serum was 1.58 μg/mL. In our proposed method, the reaction was completed in a simple one-step mixing with only one type of fluorescence-labeled Fab fragment reagent, and no washing operation was required. Therefore, rapid protein quantification was achieved with a greatly simplified procedure.

Plasmonic Optical Biosensors for Detecting C-Reactive Protein: A Review.

C-reactive protein (CRP), a potent acute-phase reactant that increases rapidly in response to inflammation, tissue damage or infections, is also considered an indicator of the risk of cardiovascular diseases and neurological disorders. Recent advances in nanofabrication and nanophotonic technologies have prompted the optical plasmonic phenomena to be tailored for specific detection of human serum CRP into label-free devices. We review the CRP-specific detection platforms with high sensitivity, which feature the thin metal films for surface plasmon resonance, nano-enhancers of zero dimensional nanostructures, and metal nanoparticles for localized surface plasmon resonance. The protocols used for various types of assay reported in literature are also outlines with surface chemical pretreatment required for specific detection of CRPs on a plasmonic surface. Properties including sensitivity and detection range are described for each sensor device reviewed, while challenges faced by plasmonic CRP sensors are discussed in the conclusion, with future directions towards which research efforts need to be made.

Electrochemical Detection of C-Reactive Protein in Human Serum Based on Self-Assembled Monolayer-Modified Interdigitated Wave-Shaped Electrode.

An electrochemical capacitance immunosensor based on an interdigitated wave-shaped micro electrode array (IDWµE) for direct and label-free detection of C-reactive protein (CRP) was reported. A self-assembled monolayer (SAM) of dithiobis (succinimidyl propionate) (DTSP) was used to modify the electrode array for antibody immobilization. The SAM functionalized electrode array was characterized morphologically by atomic force microscopy (AFM) and energy dispersive X-ray spectroscopy (EDX). The nature of gold-sulfur interactions on SAM-treated electrode array was probed by X-ray photoelectron spectroscopy (XPS). The covalent linking of anti-CRP-antibodies onto the SAM modified electrode array was characterized morphologically through AFM, and electrochemically through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The application of phosphate-buffered saline (PBS) and human serum (HS) samples containing different concentrations of CRP in the electrode array caused changes in the electrode interfacial capacitance upon CRP binding. CRP concentrations in PBS and HS were determined quantitatively by measuring the change in capacitance (ΔC) through EIS. The electrode immobilized with anti-CRP-antibodies showed an increase in ΔC with the addition of CRP concentrations over a range of 0.01–10,000 ng mL−1. The electrode showed detection limits of 0.025 ng mL−1 and 0.23 ng mL−1 (S/N = 3) in PBS and HS, respectively. The biosensor showed a good reproducibility (relative standard deviation (RSD), 1.70%), repeatability (RSD, 1.95%), and adequate selectivity in presence of interferents towards CRP detection. The sensor also exhibited a significant storage stability of 2 weeks at 4 °C in 1× PBS.

Efficient electron-mediated electrochemical biosensor of gold wire for the rapid detection of C-reactive protein: A predictive strategy for heart failure

C-reactive protein (CRP) is considered a promising biomarker for the rapid and high-throughput real-time monitoring of cardiovascular disease and inflammation in unprocessed clinical samples. Implementation of this monitoring would enable various transformative biomedical applications. We have fabricated a highly specific sensor chip to detect CRP with a detection limit of 2.25 fg/mL. The protein was immobilized on top of a gold (Au) wire/polycarbonate (PC) substrate using 1-ethyl-3-(3-dimethylamino-propyl) carbodiimide hydrochloride/N-hydroxy succinimide-activated 3-mercaptoproponic acid (MPA) as a self-assembled monolayer agent and bovine serum albumin (BSA) as a blocking agent. In contrast to the bare PC substrate, the CRP/BSA/anti-CRP/MPA/Au substrate exhibited a considerably high electrochemical signal toward CRP. The influence of the experimental parameters on CRP detection was assessed via various analysis methods, and these parameters were then optimized. The linear dynamic range of the CRP was 5–220 fg/mL for voltammetric and impedance analysis. Morever, the strategy exhibited high selectivity against various potential interfering species and was capable of directly probing trace amounts of the target CRP in human serum with excellent selectivity. The analytical assay based on the CRP/BSA/anti-CRP/MPA/Au substrate could be exploited as a potentially useful tool for detecting CRP in clinical samples.

“COMPARISON OF A RAPID SEMI-QUANTITATIVE LATEX AGGLUTINATION SLIDE METHOD AGAINST QUANTITATIVE PARTICLE ENHANCED TURBIDIMETRIC IMMUNOASSAY FOR MEASUREMENT OF C- REACTIVE PROTEIN”

Serum C - reactive protein (CRP) is an acute phase marker in humans that is useful for the diagnosis and monitoring of inflammatory disease. CRP measurement also helps in differential diagnosis, in the management of neonatal septicaemia and meningitis where standard microbiological investigations are very much time-consuming. Reliable method (Automated particle enhanced turbidimetric immunoassay) are preferable for routine evaluation of human serum CRP levels. Using such expensive methods in health centres in rural areas is not possible. The aim of this to evaluate whether human CRP levels could be measured by rapid method (Latex agglutination slide method) and compared with reliable method (particle enhanced turbidimetric immunoassay).The study included 400 participants, who attended Shree Krishna Hospital, Karamsad, whose CRP levels were done by particle enhanced turbidimetric immunoassay method in Siemens Dimension Clinical Chemistry Analyzer, RxL and Xpand and compared by rapid method (Latex Agglutination slide method), that will be useful in health centres in rural areas where expensive instruments are not available. We used SPSS for data analysis and Endnote X7 for references management. In present study, out of 400 (217 male and 183 female) participants, we found 337 participants had positive CRP levels (≥0.3 mg/dl) and 63 participants had negative CRP levels (&lt;0.3 mg/dl) by particle enhanced turbidimetric immunoassay method, whereas 303 had positive CRP levels (≥0.6mg/dl) and 97 had negative CRP levels (&lt;0.6mg/dl) by Latex Agglutination slide method. The correlation was positive between two methods with (r = 0.764, P -value &lt;0.0001). The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 89.9%, 100%, 100%, and 64.94%, respectively, for the Latex Agglutination slide method, and 100%, 64.9%, 89.91% and 100%, respectively, for the particle enhanced turbidimetric immunoassay method. Serum C- reactive protein (CRP) levels can be reliably measured using the particle enhanced turbidimetric immunoassay method, but it is expensive, so we can use Latex agglutination slide method in rural areas for primary diagnosis only.&#x0D; Key Words: CRP, Latex Agglutination slide method, particle enhanced turbidimetric immunoassay method.

High serum CRP influences myocardial miRNA profiles in ischemia-reperfusion injury of rat heart.

ObjectivePrognosis of myocardial infarction tends to be worse when serum C-reactive protein (CRP) level is high. miRNAs are also known to be involved in different pathogeneses of heart diseases such as myocardial infarction. However, how CRP is involved in myocardial infarction has not been fully elucidated. We hypothesized that serum CRP changes the miRNA profile during ischemia-reperfusion injury (IRI) of the myocardium. To confirm this hypothesis, we performed global miRNA expression profiling of myocardium using IRI and CRP infusion rat model.MethodsAfter ligation of the coronary artery of rat hearts, human serum CRP was intravenously injected, and reperfusion was performed (I/R+CRP group, n = 6). Control group consisted of the sham group (n = 3), IV CRP infusion group (CRP only, n = 3), and the I/R-only group (I/R only, n = 5). We evaluated 423 miRNA expression in non-ischemic areas and areas at risk (AAR) of each group using NanoString nCounter miRNA expression assay.ResultsMiR-124 was downregulated in non-ischemic myocardium in CRP-only group. In AAR, 7 miRNAs were commonly upregulated in both I/R-only and I/R+CRP groups. And additional 6 miRNAs were upregulated in the I/R+CRP group (miR-33, miR-409-3p, miR-384-3p, miR-3562, miR-101a, and miR-340-5p). Similarly, in the non-ischemic areas, 6 miRNAs were commonly upregulated in both I/R-only and I/R+CRP groups, and additional 5 miRNAs changed in the I/R+CRP group (upregulation of miR-3559-5p, miR-499, and miR-21 and downregulation of miR-500 and miR-532-3p).ConclusionWe showed that when serum CRP level is high, IRI results in multiple miRNA profile changes not only in ischemic areas but also in non-ischemic myocardium. Our results may provide a strong basis for studying the role of CRP and miRNAs in ischemic heart disease.

Development a stacking pad design for enhancing the sensitivity of lateral flow immunoassay

Lateral flow immunoassays (LFIAs) have wide application in point-of-care testing, particularly in resource-poor settings. To achieve signal amplification in a gold nanoparticle-based lateral flow assay without an additional procedure or the need for complex fabrication, a new and simple method was developed for using a “stacking pad” configuration that adds an additional membrane between the conjugation pad and test pad to the conventional AuNP-based LFIA format. This design helps to accumulate the antibody and antigen on the stacking pad, hence extending the antigen/antibody binding interactions to enhance the test’s detection sensitivity. With the enhanced lateral flow assay, as low as 1 ng/mL of Protein A and 15.5 ng/mL of C-reactive protein can be visualized with the naked eye. We also successfully applied the stacking pad system in the analysis of C-reactive protein in human serum and synovial fluid samples. These results suggest that this stacking pad LFIA can provide sensitive and on-site prognosis for detection in synovial fluid and serum samples in resource-limited settings.

New Generation of Ultrasensitive Label-Free Optical Si Nanowire-Based Biosensors

We demonstrate the realization of the first label-free optical biosensor based on the room temperature luminescence of silicon nanowires (NWs) tested for the selective detection of C-reactive protein in human serum. High aspect ratio Si NW arrays used as sensing interface, are synthesized by a fast, low cost and Si industrially compatible approach. Si NW optical biosensors are fast and offer a broad concentration dynamic range that can be tuned according to different applications. Moreover, the platform is endowed with a high selectivity toward the target analyte and a sensitivity down to the fM limit of detection, opening the route toward noninvasive analysis in biofluids such as saliva.

Localized protein immobilization on microstructured polymeric surfaces for diagnostic applications

We demonstrate a localized protein immobilization method based on controlled physical adsorption on the three-phase boundary of an aqueous phase, a gas phase, and a polymeric material. By imprinting micrometer and sub-micrometer pillars onto a polymeric foil, superhydrophobic surfaces are fabricated. Those structures force the fluid locally into the Cassie–Baxter state and generate an artificial three-phase boundary at the edges of the imprinted pillars. First, fluorescence-labeled bovine serum albumin (BSA) and streptavidin dissolved in various buffer solutions are utilized to investigate protein adsorption on the structured surfaces. A stable adsorption of the respective protein on the three-phase boundary is observed. The following experiments use streptavidin adsorbed on the pillars to immobilize biotinylated antibodies for analyte detection. The pillars are passivated with an excess concentration of BSA to reduce nonspecific protein adsorption. Implemented in a lab-on-a-chip device, the proposed immobilization method is utilized in a sandwich assay to detect the inflammation marker C-reactive protein in human serum, showing the potential of this immobilization method for diagnostic applications. The method overcomes laborious procedures to immobilize proteins on thermoplastic materials, which enables the fast transfer of point-of-care applications from research to commercial scale.

Effect of nutritional status and dietary patterns on human serum C-reactive protein and interleukin-6 concentrations.

The inflammatory process plays an important role in the pathogenesis of many chronic diseases, such as cardiovascular diseases, diabetes mellitus type 2, and metabolic syndrome. Serum C-reactive protein (CRP) and interleukin-6 (IL-6) are widely tested inflammatory markers involved in the development of these diseases. Several studies indicate a relation between nutritional status and the concentrations of human high-sensitivity CRP and IL-6. Similarly, the role of diet in reducing inflammation and thereby modulating the risk of non-communicable diseases is supported by numerous studies. This review focuses on the effects of the selected nutrition models in humans on the concentrations of CRP and IL-6. It seems that the Mediterranean diet model is most effective in inhibiting inflammation. The Dietary Approaches to Stop Hypertension model and the plant nutrition model also have proven to be beneficial. The data on low-fat and low-carbohydrate diets are inconclusive. Comprehensive studies are necessary, taking into account the cumulative effect of dietary and other factors on the inflammatory process.

Disposable integrated bismuth citrate-modified screen-printed immunosensor for ultrasensitive quantum dot-based electrochemical assay of C-reactive protein in human serum

A novel immunosensor based on graphite screen-printed electrodes (SPEs) modified with bismuth citrate was developed for the voltammetric determination of C-reactive protein (CRP) in human serum using quantum dots (QDs) labels. The sandwich-type immunoassay involved physisorption of CRP capture antibody on the surface of the sensor, sequential immunoreactions with CRP and biotinylated CRP reporter antibody and finally reaction with streptavidin-conjugated PbS QDs. The quantification of the target protein was performed with acidic dissolution of the PbS QDs and anodic stripping voltammetric detection of the Pb(II) released. Detection was performed at bismuth nanodomains formed on the sensor surface during the electrolytic preconcentration step, as bismuth citrate was reduced to metallic bismuth simultaneously with the deposition of Pb on the surface of the immunosensor. Under optimal conditions, the response was linear over the range 0.2–100 ng mL−1 CRP and the limit of detection was 0.05 ng mL−1 CRP. Since the modified SPE serves as both the biorecognition element and the QDs reader, the analytical procedure is simplified, the drawbacks of existing electroplated immunosensors are minimized while the proposed disposable sensing platform provides convenient, low-cost and ultrasensitive detection of proteins and wider scope for mass-production.