Detection Of C-reactive Protein Research Articles

C-Reactive Protein Biosensor for Diagnosing Infections Caused by Orthopedic Trauma.

Infections linked to orthopedic trauma are common complications that place a significant strain on the healthcare system. Immediate identification of the infection and its severity is essential for providing effective treatment. C-reactive Protein (CRP) is a commonly used inflammatory marker in orthopedic surgery and has proven to be a valuable biomarker for diagnosing and monitoring infections. Specifically, CRP aids in the early identification of postoperative infections. This research work has focused on developing a highly sensitive CRP biosensor using iron oxide nanomaterial-modified dielectric sensors. Gold Urchin (GU)-conjugated aptamers and antibodies were used as probes and attached to the electrode via amine linkers. The aptamer-GU-antibody-modified electrode detected CRP at concentrations as low as 1 pg/mL, with an R2 value of 0.9942. Furthermore, CRP-spiked serum exhibited an increase in current response at all concentrations of CRP, indicating selective detection of CRP. Additionally, control experiments using complementary sequences of the aptamer, relevant proteins, and non-immune antibodies did not enhance the current responses, confirming the specific identification of CRP. The sensing strategy has enabled the detection of CRP at its lowest levels, facilitating the identification of infections during orthopedic surgery and subsequent treatment.

Diagnostic Accuracy of Combined Measurement of Serum Homocysteine, C-Reactive Protein, and Serum Ferritin in Mild Cognitive Impairments and Alzheimer's Disease.

Evaluation of the diagnostic accuracy of combined detection of serum homocysteine (Hcy), C-reactive protein (CRP), and serum ferritin (SF) levels in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). Descriptive study. Place and Duration of the Study: Clinical Laboratory Section, Affiliated Hospital of Hebei University, Baoding, Heibei, China, from May 2022 to June 2023. Data of 120 patients with memory decline were retrospectively collected. They were divided into an MCI group and an AD group. A further 50 healthy participants were used as a normal control (NC) group. Differences in the Hcy, CRP, and SF levels between the three groups were evaluated. The specificity, accuracy, and sensitivity of these three indices in the combined or single diagnosis of AD and MCI were compared. Their associations with the severity of AD and MCI were also compared. The AD group had the highest levels of Hcy, CRP, and SF (18.79 ± 4.50, 6.35 ± 2.04, and 355.69 ± 120.36), followed by MCI (16.75 ± 3.06, 4.58 ± 2.31, and 203.48 ± 12.76), and NC group (14.32 ± 2.06, 2.06 ± 0.76, and 98.46 ± 5.06), with statistically significant differences (all p <0.001). The diagnostic efficacy of AD for CRP was 98.50%, sensitivity was 96.00%, and specificity was 94.00%, which was higher than Hcy and SF. Tested together, the area under the ROC curve was 99.90%, specificity was 98.00%, and sensitivity was 98.00%. The diagnostic efficacy of SF for MCI had sensitivity of 100.00%, and specificity of 100.00%, which was higher than that of Hcy and CRP. When the three were combined for detection, the area under the curve of SF was 100.00%, sensitivity of 100.00%, and specificity of 100.00%. The levels of Hcy, CRP, and SF were positively correlated with the severity of AD (p <0.01), while negatively correlated with the mini-mental state examination (MMSE) score (p <0.01). The combined detection of Hcy, CRP, and SF improved the diagnostic accuracy of comorbid AD and MCI. Homocysteine, C-reactive protein, Cognitive impairment, Serum ferritin, Alzheimer's disease.

Diagnostic Accuracy of Combined Measurement of Serum Homocysteine, C-Reactive Protein, and Serum Ferritin in Mild Cognitive Impairments and Alzheimer's Disease.

Evaluation of the diagnostic accuracy of combined detection of serum homocysteine (Hcy), C-reactive protein (CRP), and serum ferritin (SF) levels in patients with Alzheimer's disease (AD) and mild cognitive impairment (MCI). Descriptive study. Place and Duration of the Study: Clinical Laboratory Section, Affiliated Hospital of Hebei University, Baoding, Heibei, China, from May 2022 to June 2023. Data of 120 patients with memory decline were retrospectively collected. They were divided into an MCI group and an AD group. A further 50 healthy participants were used as a normal control (NC) group. Differences in the Hcy, CRP, and SF levels between the three groups were evaluated. The specificity, accuracy, and sensitivity of these three indices in the combined or single diagnosis of AD and MCI were compared. Their associations with the severity of AD and MCI were also compared. The AD group had the highest levels of Hcy, CRP, and SF (18.79 ± 4.50, 6.35 ± 2.04, and 355.69 ± 120.36), followed by MCI (16.75 ± 3.06, 4.58 ± 2.31, and 203.48 ± 12.76), and NC group (14.32 ± 2.06, 2.06 ± 0.76, and 98.46 ± 5.06), with statistically significant differences (all p <0.001). The diagnostic efficacy of AD for CRP was 98.50%, sensitivity was 96.00%, and specificity was 94.00%, which was higher than Hcy and SF. Tested together, the area under the ROC curve was 99.90%, specificity was 98.00%, and sensitivity was 98.00%. The diagnostic efficacy of SF for MCI had sensitivity of 100.00%, and specificity of 100.00%, which was higher than that of Hcy and CRP. When the three were combined for detection, the area under the curve of SF was 100.00%, sensitivity of 100.00%, and specificity of 100.00%. The levels of Hcy, CRP, and SF were positively correlated with the severity of AD (p <0.01), while negatively correlated with the mini-mental state examination (MMSE) score (p <0.01). The combined detection of Hcy, CRP, and SF improved the diagnostic accuracy of comorbid AD and MCI. Homocysteine, C-reactive protein, Cognitive impairment, Serum ferritin, Alzheimer's disease.

Detection of C-reactive protein using a label-free NIR fluorescent aptasensor with a large Stokes shift based on an AIEE anthracene derivative

BackgroundC-reactive protein (CRP), one of the classic biomarkers of inflammation, is closely related to infectious inflammation, cardiovascular disease, cancer, and other diseases. Therefore, timely and accurate detection of CRP in human blood is crucial for the discovery, diagnosis, and treatment of the aforementioned diseases. Herein, a novel label-free NIR fluorescence aptasensor with a large Stokes shift based on an AIEE anthracene derivative B and a molybdenum disulfide (MoS2) platform was developed and used for the high sensitivity and specificity detection of CRP. ResultsCompound B could emit near-infrared (NIR) fluorescence with a large Stokes shift (190 nm). Notably, this compound could bind with the aptamer of CRP (CRP-Apt) through electrostatic attraction to form a B/CRP-Apt complex, generating an aggregation-induced emission enhancement effect and enhancing the fluorescent intensity of B. B/CRP-Apt could be adsorbed on the surface of MoS2 with the addition of MoS2 to its solution, and the fluorescence of Compound B was quenched. CRP was then added to the above solution. CRP-Apt had a substantially higher affinity for CRP than MoS2. Therefore, B/CRP-Apt detached from the surface of MoS2 and bound to CRP, thereby restoring the fluorescence of B. Experimental results showed a good linear relationship between the fluorescent recovery intensity of B and the concentration of CRP in the concentration range of 0.3–70 ng mL−1, with a limit of detection as low as 0.1 ng mL−1. Significance and NoveltyThe aptasensor integrates the advantages of high sensitivity of NIR fluorescence, high specificity of aptamers, good water-solubility and AIEE effect of Compound B. And it could be applied to the determination of CRP in human serum samples, while most of the reported methods can only determine CRP in spiked human serum samples.

A dual-aptamer sandwich assay by detection of c-reactive protein in synovial fluid on an integrated microfluidic system for diagnosis of periprosthetic joint infection

Diagnosing periprosthetic joint infection (PJI) in equivocal cases is always challenging. Synovial fluid (SF) C-reactive protein (CRP) levels have been reported as a surrogate to improve the diagnosis accuracy. This study reported a new integrated microfluidic system (IMS) designed to detect SF-CRP at a dynamic range of 1-50mg/L. The novel, magnetic bead-based, dual-aptamer assay with two CRP-specific aptamers, St1 and St2, enabled rapid and accurate CRP detection. This represents the first attempt to automatically perform the CRP dual-aptamer assay on a microfluidic chip quantifying CRP in SF with optical signals. CRP concentrations in fourteen clinical samples were accurately quantified by using the dual-aptamer assay on the developed IMS in an automatic format, suggesting the assay’s potential as a reliable diagnostic tool for SF-CRP detection and may serve as an armamentarium for PJI diagnosis. Notably, the assay was deemed superior to traditional enzyme-linked immunosorbent assay (ELISA) because it consumes a smaller amount of sample (only 40μL), requires fewer reagents (only 50μL of secondary detection aptamer and horseradish peroxidase), and provides quicker results (~2hours).

Dual-Fluorescent Quantum Dot Nanobead-Based Lateral Flow Immunoassay for Simultaneous Detection of C-Reactive Protein and Procalcitonin.

Simultaneous detection of C-reactive protein (CRP) and procalcitonin (PCT) at the point of care is crucial for the management of infections in patients with inflammation and in critical care settings. The challenge of detecting high concentrations of CRP alongside low concentrations of PCT in plasma from inflammatory patients has limited the clinical application of multiplexed immunoassays. Herein, we developed a lateral flow immunoassay (LFIA) that employs quantum dot nanobeads (QDNBs) of varying sizes and colors to enable the simultaneous quantification of PCT and CRP in human plasma. To extend the dynamic range of CRP detection, we combined QDNBs with smaller particle sizes with the CRP detection antibodies, thereby increasing the assay's dynamic range and reducing the hook effect. At the same time, the stronger fluorescence emitted by these larger QDNBs, in conjugation with the PCT detection antibodies, allows for the detection of PCT at the nanogram level, meeting the demand for high sensitivity. The results show that this method can detect CRP concentrations from 0.1 to 3 mg/L and PCT with a detection limit of 0.09 ng/mL, which is on par with clinically used methods. By employing this dual-color and dual-size QDNB labeling strategy, we successfully achieved simultaneous detection of CRP with a broad dynamic range and PCT with high sensitivity in a one-step point-of-care rapid test.

Enzyme-free immunoassay for rapid, sensitive, and selective detection of C-reactive protein.

C-reactive protein (CRP) is a protein made by the liver, which is released into the bloodstream in response to inflammation. Furthermore, CRP is a potential risk factor for heart disease. Hence, it is of great importance to develop a rapid, sensitive, accurate, and cost-effective method for CRP detection. Herein, we report an enzyme-free fluorescent assay for the rapid and ultra-sensitive detection of CRP with a limit of detection (LOD) reaching as low as 3.08 pg/mL (i.e., ~ 27 fM). The high sensitivity of our method was simply achieved via dual-functionalized gold nanoparticles (AuNPs). By regulating the molar ratio of DNA to CRP antibody immobilized on the AuNP surface, hundreds to thousands-fold amplification in the analyte signal could be instantly accomplished. Furthermore, our sensor was selective: non-target proteins such as interleukin-6, interleukin-1β, procalcitonin, bovine serum albumin, and human serum albumin did not interfere with the target CRP detection. Moreover, simulated serum samples were successfully analyzed. Given the excellent sensitivity, selectivity, and high resistance to complicated matrices, the enzyme-free CRP detection strategy developed in this work can be used as a generic platform to construct sensors for a wide variety of protein biomarkers and hence offers potential as a tool for rapid, accurate, and low-cost medical diagnosis.

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.

Fabrication of core-shell quantum dots microbeads with high stability, enhanced sensitivity and potential application in C-reactive protein (CRP) and procalcitonin (PCT) immunochromatography in vitro diagnostic reagents

Cardiovascular and cerebrovascular diseases represent the leading causes of mortality among middle-aged and elderly populations in China, with inflammation identified as a significant contributing factor. Consequently, the early diagnosis and management of inflammation are of paramount importance. C-reactive protein (CRP) and procalcitonin (PCT) serve as biomarkers for myocardial inflammation. In this study, we developed a quantum dot immunochromatographic strip that was capable of simultaneously detecting these two biomarkers with enhanced sensitivity and specificity. The comb amphiphilic poly (octadecyl-alt-polyethylene glycol) was synthesized through an amide reaction, which was employed to coat oil-soluble quantum dots, thereby transforming them into water-soluble quantum dots microbeads suitable for the coupling with biological macromolecules. These quantum dots microbeads were utilized as luminescent materials in the immunochromatographic strip for the concurrent detection of CRP and PCT. The assay required only 100 μL of sample and provided results within 10 min, demonstrating commendable precision, stability, sensitivity, and accuracy. Clinical evaluations confirmed that the developed CRP and PCT quantum dots immunochromatographic test strips were accurate and reliable, underscoring their significant potential for practical routine clinical application in the early accurate diagnosis of myocardial inflammation.

Chemiluminescence Immunoassay for Sensitive Detection of C-reactive Protein Using Graphene Oxide–Gold Nanoparticle–Luminol Hybrids as Enhanced Luminogenic Molecules

Chemiluminescence Immunoassay for Sensitive Detection of C-reactive Protein Using Graphene Oxide–Gold Nanoparticle–Luminol Hybrids as Enhanced Luminogenic Molecules

Plasmonic sensing platform for C-reactive protein recognition via synthetic receptors decorated on graphene oxide and gold nanoparticles

C-reactive protein (CRP) level provides important information about the health status of the individual in predicting many diseases such as cardiovascular, chronic inflammatory, and neurodegenerative diseases. Therefore, determining CRP levels is important for correct health intervention and treatment follow-up. For the selective detection of CRP, we developed a (GO/Au-MIP) SPR sensor containing CRP-imprinted polymer modified with graphene oxide and gold nanoparticles. To prove the enhanced sensitivity of the sensor resulting from the presence of graphene oxide (GO) and gold nanoparticles (AuNPs), a CRP-imprinted (MIP) SPR sensor was prepared using the same method, excluding the incorporation of GO and AuNPs. In addition, a non-imprinted GO/Au-NIP SPR sensor was also prepared to evaluate the imprinting efficiency. In detecting CRP in PBS buffer, the GO/Au-MIP SPR sensor exhibited linearity in the concentration ranges of 0.1–2 ppm (R2 = 0.9721) and 5–100 ppm (R2 = 0.9740). The detection limit of the prepared sensor was calculated as 0.0082 ppm. In the study, the imprinting process efficiency was also evaluated by calculating the imprinting factor value (I.F=13.84). In the selectivity studies, the GO/Au-MIP SPR sensor was determined to be 9.23 times more selective against CRP protein than bovine serum albumin and 29.53 times more selective than hemoglobin. When the repeatability of the GO/Au-MIP SPR sensor was examined, it was determined that the GO/Au-MIP SPR sensor was able to detect CRP without any deterioration in performance in five consecutive reuses (RSD<1.5). Finally, CRP detection studies from the serum and urine solutions, which were selected as real samples, were carried out by the GO/Au-MIP SPR sensor to evaluate the matrix effect. CRP spiked serum sample was analyzed by the other standard method to validate the analytical results using CRP analyser.

Reagent-free anti-fouling electrochemical immunosensor based on AL-BSA/AuNPs/PANI coating for the point-of-care detection of C-reactive protein in plasma and whole blood

Developing the portable CRP detection technologies that are suitable for point-of-care (POC) and primary care management is of utmost importance, and advancing the electrochemical immunosensors hold promise for POC implementation. Nevertheless, non-specific adsorption of numerous interfering proteins in complex biological media contaminates immunosensors, thereby restricting the reliability in detection efficacy. In this study, a three-dimensional flower-leaf shape amyloid bovine serum albumin/gold nanoparticles/polyaniline (AL-BSA/AuNPs/PANI) coating on the surface of the electrode was developed, which demonstrated strong anti-adsorption properties against bovine serum albumin, plasma, and cells. The immunosensor exhibited a good linear relationship to CRP response, featuring a detection limit of 0.09 μg/mL, consistent with clinical reference range. In addition, the CRP immunosensor demonstrated excellent specificity in other inflammation-related proteins and commendable anti-interference performance for CRP detection in plasma and whole blood tests. Importantly, by combining the development of a USB flash disk-type portable electrochemical workstation with a reagent-free mode, the developed CRP electrochemical immunosensor delivered ideal results in clinical samples. The anti-fouling performance, sensitivity and specificity of the immunosensor, as well as its flexible test modes in clinical samples, provide important scientific basis for developing POC detection technologies of vital biomarkers in complex biological media.

Laboratory profiling of patients with long COVID in the Brazilian Amazon region: A cross-sectional study.

The condition commonly referred to as long coronavirus disease (COVID) is characterized by the continuation of symptoms, sometimes accompanied by new symptoms that persist after the resolution of acute coronavirus disease 2019 (COVID-19). This observational cross-sectional study investigated 332 patients with long COVID in the Brazilian Amazon region. The study aimed to elucidate the systemic interactions associated with long COVID by compiling the findings related to hematological, coagulation, immunological, metabolic, hepatic, renal, and muscular profiles. Participants with long COVID were identified using rigorous criteria and underwent thorough laboratory examinations. The obtained data were subsequently analyzed, allowing for comparisons, associations, and correlations between findings within distinct groups in the study. Significant associations were observed between hospitalization during the acute phase and persistent laboratory abnormalities, suggesting a potential link between acute severity and long-term effects. Notably, individuals with long COVID for over a year exhibited elevated levels of monocytes, prolonged prothrombin times, reduced prothrombin activity, high levels of lactate dehydrogenase, and an increased frequency of qualitative C-reactive protein detection. This study provides valuable insights into the laboratory risk profile of patients with long COVID, particularly in the unique context of the Amazon region, where patients exhibit persistent symptoms lasting up to 1261 days.

EGaIn-Modified ePADs for Simultaneous Detection of Homocysteine and C-Reactive Protein in Saliva toward Early Diagnosis of Cardiovascular Disease.

Homocysteine (Hcy) and C-reactive protein (CRP) are critical biomarkers for numerous chronic diseases, with cardiovascular disease (CVD) being the most prevalent. The ability to simultaneously detect both biomarkers in point-of-care settings is in high demand for CVD early diagnosis and prevention. Herein, we prepared the eutectic gallium indium (EGaIn) nanoparticles decorated with p-phenylenediamine (PPD) on the surface to facilitate the subsequent attachment of gold nanoparticles (AuNPs) to achieve EGaIn-PPD@Au, which was modified on the screen-printed electrochemical paper-based analytical devices (ePADs). Aptamers that are specific to Hcy and CRP were then immobilized on the EGaIn-PPD@Au surface to achieve the sensing interface on ePADs. The presence of EGaIn-PPD@Au significantly enhanced the electrical conductivity, leading to amplified electrochemical signals. This aptasensor demonstrated high specificity, capable of detecting Hcy in a range of 1-50 μM with a detection limit of 0.22 μM, and the detection range for CRP was 1-100 ng/mL with a detection limit of 0.039 ng/mL. The aptasensor also effectively detected Hcy and CRP in clinical saliva samples, yielding an area under the curve (AUC) of about 0.80 when the individual biomarker was considered and 0.93 when both biomarkers were taken into account. The positive correlation observed between salivary and blood concentrations of Hcy and CRP, coupled with their association with cardiovascular disease (CVD), suggested the potential of this methodology as a noninvasive point-of-care strategy for the early diagnosis of CVD.

Correlation between serum nitric oxide synthase levels and readmission due to acute exacerbation within 30 days in patients with acute exacerbations of chronic obstructive pulmonary disease

To explore the correlation between serum nitric oxide synthase (NOS) levels and readmission due to acute exacerbation within 30 days in patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD). A prospective cohort study was conducted. The AECOPD patients admitted to the First Affiliated Hospital of Hebei North University from January 2020 to December 2022 were enrolled as the research subjects. The general data such as gender, age, body mass index (BMI), chronic obstructive pulmonary disease (COPD) course, smoking history, and basic diseases were collected. The laboratory indicators, serum NOS level [inducible nitric oxide synthase (iNOS), endothelial nitric oxide synthase (eNOS), neuronal nitric oxide synthase (nNOS)] and acute physiology and chronic health evaluation II (APACHE II) score within 24 hours after admission and total length of hospital stay were also collected, and whether patients were readmitted due to acute exacerbation within 30 days after discharge were recorded. The differences in the above clinical indexes between the readmitted and non-readmitted patients within 30 days were compared. Multivariate Logistic regression analysis was used to screen the influencing factors of readmission within 30 days after discharge in AECOPD patients. Receiver operator characteristic curve (ROC curve) was drawn to analyze the predictive value of various influencing factors on readmission. A total of 168 patients were enrolled, 38 patients were readmitted due to acute aggravation within 30 days after discharge, and 130 were not readmitted. Compared with the non-readmission group, the levels of white blood cell count (WBC), C-reactive protein (CRP), APACHE II score, and serum iNOS and eNOS levels within 24 hours after admission in the readmission group were significantly increased [WBC (×109/L): 14.19 (12.88, 16.12) vs. 11.81 (10.63, 14.11), CRP (mg/L): 51.41±12.35 vs. 40.12±7.79, APACHE II score: 22.0 (19.0, 25.0) vs. 18.0 (14.0,20.5), iNOS (μg/L): 5.87±1.36 vs. 4.52±0.89, eNOS (μg/L): 4.40±1.00 vs. 3.51±1.08, all P < 0.01], and the levels of hemoglobin (Hb) and albumin (Alb) were significantly decreased [Hb (g/L): 108.82±22.06 vs. 123.98±24.26, Alb (g/L): 30.28±3.27 vs. 33.68±2.76, both P < 0.01]. There were no significant differences in gender, age, BMI, COPD course, smoking history, basic diseases, total length of hospital stay and serum nNOS level between the two groups. Multivariate Logistic regression analysis showed that CRP [odds ratio (OR) = 1.201, 95% confidence interval (95%CI) was 1.075-1.341], APACHE II score (OR = 1.335, 95%CI was 1.120-1.590), and serum iNOS (OR = 5.496, 95%CI was 2.143-14.095) and eNOS (OR = 3.366, 95%CI was 1.272-8.090) were the independent risk factors for readmission within 30 days after discharge in AECOPD patients (all P < 0.05), and Hb (OR = 0.965, 95%CI was 0.933-0.997) and Alb (OR = 0.551, 95%CI was 0.380-0.799) were protective factors (both P < 0.05). ROC curve analysis showed that serum iNOS and eNOS levels had predictive value for readmission within 30 days after discharge in AECOPD patients, and the area under the ROC curve (AUC) was 0.791 (95%CI was 0.694-0.887) and 0.742 (95%CI was 0.660-0.823), respectively. When the optimal cut-off value was 5.22 μg/L and 3.82 μg/L, the sensitivity was 81.54% and 69.23%, and the specificity was 71.05% and 81.58%, respectively. The AUC of serum iNOS and eNOS levels combined with Hb, Alb, CRP and APACHE II score for predicting the readmission was 0.979 (95%CI was 0.958-1.000), the sensitivity was 91.54%, and the specificity was 97.37%. The increased serum iNOS and eNOS levels of AECOPD patients correlate with the readmission due to acute exacerbation within 30 days after discharge. Combined detection of Hb, Alb, CRP, serum iNOS and eNOS levels, and evaluation of APACHE II score within 24 hours after admission can effectively predict readmission.

NFC Smartphone-Based Electrochemical Microfluidic Device Integrated with Nanobody Recognition for C-Reactive Protein.

Point-of-care testing (POCT) devices play a crucial role as tools for disease diagnostics, and the integration of biorecognition elements with electronic components into these devices widens their functionalities and facilitates the development of complex quantitative assays. Unfortunately, biosensors that exploit large conventional IgG antibodies to capture relevant biomarkers are often limited in terms of sensitivity, selectivity, and storage stability, considerably restricting the use of POCT in real-world applications. Therefore, we used nanobodies as they are more suitable for fabricating electrochemical biosensors with near-field communication (NFC) technology. Moreover, a flow-through microfluidic device was implemented in this system for the detection of C-reactive protein (CRP), an inflammation biomarker, and a model analyte. The resulting sensors not only have high sensitivity and portability but also retain automated sequential flow properties through capillary transport without the need for an external pump. We also compared the accuracy of CRP quantitative analyses between commercial PalmSens4 and NFC-based potentiostats. Furthermore, the sensor reliability was evaluated using three biological samples (artificial serum, plasma, and whole blood without any pretreatment). This platform will streamline the development of POCT devices by combining operational simplicity, low cost, fast analysis, and portability.

Polyaromatic Hydrocarbon-Functionalized 2D MXene-Based 3D Porous Antifouling Nanocomposite with Long Shelf Life for High-Performance Electrochemical Immunosensor Applications.

Affinity-based electrochemical (AEC) biosensors have gained more attention in the field of point-of-care management. However, AEC sensing is hampered by biofouling of the electrode surface and degradation of the antifouling material. Therefore, a breakthrough in antifouling nanomaterials is crucial for the fabrication of reliable AEC biosensors. Herein, for the first time, we propose 1-pyrenebutyric acid-functionalized MXene to develop an antifouling nanocomposite to resist biofouling in the immunosensors. The nanocomposite consisted of a 3D porous network of bovine serum albumin cross-linked with glutaraldehyde with functionalized MXene as conductive nanofillers, where the inherited oxidation resistance property of functionalized MXene improved the electrochemical lifetime of the nanocomposite. On the other hand, the size-extruded porous structure of the nanocomposite inhibited the biofouling activity on the electrode surface for up to 90 days in real samples. As a proof of concept, the antifouling nanocomposite was utilized to fabricate a multiplexed immunosensor for the detection of C-reactive protein (CRP) and ferritin biomarkers. The fabricated sensor showed good selectivity over time and an excellent limit of detection for CRP and ferritin of 6.2 and 4.2 pg/mL, respectively. This research successfully demonstrated that functionalized MXene-based antifouling nanocomposites have great potential to develop high-performance and low-cost immunosensors.

Rapid Microfluidic Immuno-Biosensor Detection System for the Point-of-Care Determination of High-Sensitivity Urinary C-Reactive Protein.

A microfluidic immuno-biosensor detection system consisting of a microfluidic spectrum chip and a micro-spectrometer detection device is presented for the rapid point-of-care (POC) detection and quantification of high-sensitivity C-reactive protein (hs-CRP) in urine. The detection process utilizes a highly specific enzyme-linked immunosorbent assay (ELISA) method, in which capture antibodies and detection antibodies are pre-deposited on the substrate of the microchip and used to form an immune complex with the target antigen. Horseradish peroxidase (HRP) is added as a marker enzyme, followed by a colorimetric reaction using 3,3',5,5'-tetramethylbenzidine (TMB). The absorbance values (a.u.) of the colorimetric reaction compounds are measured using a micro-spectrometer device and used to measure the corresponding hs-CRP concentration according to the pre-established calibration curve. It is shown that the hs-CRP concentration can be determined within 50 min. In addition, the system achieves recovery rates of 93.8-106.2% in blind water samples and 94.5-104.6% in artificial urine. The results showed that the CRP detection results of 41 urine samples from patients with chronic kidney disease (CKD) were highly consistent with the conventional homogeneous particle-enhanced turbidimetric immunoassay (PETIA) method's detection results (R2 = 0.9910). The experimental results showed its applicability in the detection of CRP in both urine and serum. Overall, the results indicate that the current microfluidic ELISA detection system provides an accurate and reliable method for monitoring the hs-CRP concentration in point-of-care applications.

Electrochemical biosensor based on RNA aptamer and ferrocenecarboxylic acid signal probe for C-reactive protein detection

Monitoring health-related biomarkers using fast and facile detection techniques provides key physicochemical information for disease diagnosis or reflects body health status. Among them, electrochemical detection of various bio-macromolecules, e.g., the C-reactive protein (CRP), is of great interest in offering potential diagnosis for acute inflammation caused by infections, heart diseases, etc. Herein, a novel electrochemical aptamer biosensor was constructed from Ti3C2Tx MXene and in-situ reduced Au NPs for thiolated-RNA aptamer immobilization and CRP protein detection using Fc(COOH) as the signal probe. The sensory performances for CRP detection were optimized based on working conditions, including the incubation times and the pH. The large surface area offered by Ti3C2Tx MXene and high electrical conductivity originating from Au NPs endowed the as-fabricated aptamer biosensor with a decent sensitivity for CRP in a wide linear range of 0.05–80.0 ng/mL, good selectivity over interfering substances, and a low detection limit of 0.026 ng/mL. Such aptamer biosensors also detected CRP in serum samples using the spike & recovery method with reasonable recovery rates. The results demonstrated the potential of the as-fabricated electrochemical aptamer biosensor for fast and facile CRP detection in practical applications.

Label-free electrochemical detection of glycated hemoglobin (HbA1c) and C-reactive protein (CRP) to predict the maturation of coronary heart disease due to diabetes

The pathophysiological link between diabetes and heightened propensity for the development of coronary heart disease (CHD) is well-established. Prevailing evidence confirms that small increases in low concentrations of high-sensitivity C reactive protein (hs-CRP) in the human body can determine the tendency of developing CHD. Additionally, glycated hemoglobin (HbA1c) is a well-recognized biomarker to evaluate diabetes progression. Given the positive correlation between diabetes and CHD, this research presents a notably unprecedented label-free electrochemical approach for the dual detection of %HbA1c regarding Total Hb and hs-CRP, facilitating early CHD prediction and cost-effective point-of-care diagnostics. Furthermore, a novel redox probe O-(4-Nitrophenylphosphoryl)choline (C11H17N2O6P) was used for the electrochemical detection of CRP, a method not documented in scientific literature before. The calibration curves demonstrate a limit of detection (LOD) of 5 mg/mL in PBS (pH 8) and 6 mg/mL in simulated blood (SB) for a linear range of 0–30 mg/mL of HbA1c. Conjointly, a LOD of 0.007 mg/mL and 0.008 mg/mL for measurement in PBS (pH 7.4) and SB are reported for a linear range of 0–0.05 mg/mL of CRP. The electrochemical systems presented could accurately quantify HbA1c and CRP in mixed samples, demonstrating reasonable specificity and practical applicability for complex biological samples.