Detection Of Procalcitonin Research Articles

Quantitative and simultaneous detection of two inflammation biomarkers via a fluorescent lateral flow immunoassay using dual-color SiO2@QD nanotags.

Anon-site detection strategy is reportedbased on dual-color SiO2@quantum dot (QD)-integrated lateral flow immunoassay (LFA) strip to realize the quantitative and simultaneous detection of C-reactive protein (CRP) and procalcitonin (PCT) in serum. The dual-color SiO2@QD nanotags with monodispersity and excellent luminescence were synthesized using polyethyleneimine-mediated electrostatic adsorption of dense red CdSe/ZnS-COOH (excitation/emission 365/625nm) or green CdSe/ZnS-COOH (excitation/emission 365/525nm) QDs on the surface of 180nm SiO2 spheres and were conjugated with anti-PCT and anti-CRP monoclonal antibodies, as stable and fluorescent-enhanced QD nanotags in the LFA system. The use of SiO2@QDs with two different fluorescent signals causedthe sensitivity and specificity of themultiplex LFA system. As a result, the proposed assay provided a wide logarithmic determinationrange with a CRP quantitative range of 0.5-103ng/mL and PCT quantitative range of 0.05-103ng/mL. The limits of detection (LODs) of CRP and PCT reached 0.5 and 0.05ng/mL, respectively. The SiO2@QD-based LFA showed great potential as rapid detection tool for the simultaneous monitoring of CRP and PCT in serum sample.

Quantum dot nanobead-based immunochromatographic assay for the quantitative detection of the procalcitonin antigen in serum samples

Procalcitonin (PCT) is a indicator for the evaluation of severe sepsis caused by bacterial infection. A highly luminescent quantum dot bead (QB) was synthesized and used as an alternative of gold nanoparticles (AuNPs) to improve the sensitivity of immunochromatographic assay (ICA) for quantitative PCT detection. Various parameters influenced the performance of QB-based ICA (QB-ICA) were systematically investigated. Under the optimized conditions, QB-ICA exhibits a wide dynamic linear range of 0.0625–400 ng/mL for the quantitative PCT determination of serum. The limit of detection of QB-ICA is 0.0625 ng/mL, which is about 10-fold lower than that of conventional AuNP-based ICA. The average recoveries of intra-assays and inter-assays ranged from 86.6% to 114.1% with coefficients of variation ranging from 7.1% to 13.7%. These results indicate the QB-ICA has an acceptable accuracy and precision for PCT detection. The QB-ICA shows high specificity for quantitative PCT detection and strong resistance to common interfering matrices in real serum samples. Additionally, the developed QB-ICA exhibits excellent agreement with the chemiluminescence immunoassay by detecting 35 serum samples which were confirmed the systemic inflammatory response by infectious diseases, and showing no false positive result in analyzing 40 serum samples collected from healthy persons. In conclusion, the proposed QBs can serve as a signal amplification probe to improve the sensitivity of the ICA platform.

Procalcitonin Detection in Veterinary Species: Investigation of Commercial ELISA Kits.

Simple SummaryAmong sepsis biomarkers, procalcitonin resulted to be a specific indicator of bacterial infection or severity of infection, and to be a good control of the success of a therapeutic procedure. The clinical studies on the relevance of procalcitonin as a sepsis predictor in veterinary patients are few, likely due to the total absence of validated assays. For this reason, this study aimed to investigate commercial ELISA kits for the detection of canine and equine procalcitonin. Validation was performed evaluating linearity, limits of detection (LOD), recovery, and intra-assay and inter-assay variability; furthermore, clinical samples were analyzed. The results of the present study demonstrate that the human PCT ELISA kit is suitable to detect equine procalcitonin with a LOD of 56 ng/mL, and the canine recombinant PCT ELISA kit can be used to measure canine procalcitonin in plasma samples, showing an intra-assay and inter-assay coefficient of variation less than 20% and a LOD of 11 pg/mL.In human medicine, procalcitonin (PCT), the precursor of calcitonin, is used for the rapid identification of the origin and severity of sepsis. In veterinary medicine, PCT has been studied in horses, cattle, and dogs, but the use of PCT in diagnostic and/or prognostic settings is not possible because of the lack of validated assays to obtain reference ranges. The aim of the present study was the investigation of commercially available ELISA kits for the detection of canine and equine PCT in plasma samples. Validation of the ELISA kits was performed by using species-specific recombinant proteins spiked both in plasma and buffer samples; linearity, limit of detection (LOD), recovery, and intra-assay and inter-assay variability were calculated. Moreover, clinical samples obtained from sick and healthy animals were also analyzed with the tested kits. Canine PCT was measured with a recombinant canine and a canine PCT ELISA kit. Equine PCT was measured with an equine and a human ELISA PCT kit. Our data demonstrate that the canine recombinant PCT ELISA kit can be used to measure canine PCT in plasma samples, showing an intra-assay and inter-assay coefficient of variation less than 20% and a LOD of 11 pg/mL, whereas the present results do not support the use of the canine PCT ELISA kit. The human PCT ELISA kit is suitable to detect equine PCT with a LOD of 56 ng/mL, whereas the equine PCT ELISA kit did not detect recombinant equine PCT.

The diagnostic value of serum C-reactive protein, procalcitonin, interleukin-6 and lactate dehydrogenase in patients with severe acute pancreatitis

ObjectiveAcute pancreatitis (AP) is an inflammatory disease with rapid progression. In severe cases, it can cause systemic inflammatory response syndrome (SIRS), multiple organ failure (POF) and even death. The study aimed to investigate the diagnostic value of C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6) and lactate dehydrogenase (LDH) in patients with severe AP. MethodsAP patients (n = 153) divided into mild AP patients (n = 81) and severe AP patients (n = 72) were selected from June 2014 to June 2016. The demographic information (age, sex) and the hematological parameters (WBC, PLT, CRP, PCT, IL-6, LDH and so on) were analyzed. ResultsSignificant differences were found out of CRP, PCT, IL-6 and LDH values between AP patients and controls (P < 0.05), even those results had significant difference between MAP group and SAP group (P < 0.05). In SAP group, the cut-off values of CRP, PCT, IL-6 and LDH were 16.62, 2.29, 16.66, 273.04; sensitivity 55.6%, 77.8%, 80.2%, 82.7%; specificity 73%, 94%, 85%, 96% and AUC 0.637, 0.929, 0.886, 0.919, respectively. The AUC of combined detection of CRP, PCT, IL-6 and LDH was 0.989 (95%CI). ConclusionThe combined detection of CRP, PCT, IL-6 and LDH has a high diagnostic value for judging the severity of AP.

Development of a novel chemiluminescence immunoassay for the detection of procalcitonin

ObjectiveTo evaluate the analytical performance of our previously developed chemiluminescence immunoassay (CLIA) kit for the detection of procalcitonin (PCT) and compare with the results obtained using the Vidas B.R.A.H.M.S. PCT™ test (PCT-V). Design and methodsOur laboratory previously designed a novel CLIA kit and supporting instrument (AE-180) for the detection of PCT. We analyzed the clinical performance of this system, including the imprecision, limit of detection, and linearity of analyses of 305 serum specimens. The results were compared with measurements of the same serum samples obtained with PCT-V. ResultsThe limit of detection and blank of our kit were 0.0075 and 0.0039 ng/mL, respectively. The intra- and inter-assay coefficient of variation of the kit were both between 0.8% and 3.9%. The equation of linearity was found to be y = 1.03× + 0.06 (r = 0.99) for concentrations in the range of 0.01–110 ng/mL. The correlation coefficient with the results of PCT-V was 0.995, and the equation obtained for Passing and Bablok regression analysis was 1.061 for our CLIA PCT kit and − 0.003 for PCT-V. Our kit slightly overestimated the concentration according to comparison with PCT-V results. ConclusionThe kit that was previously developed in our laboratory for the measurement of serum PCT concentration using CLIA technology shows excellent performance, just that the functional sensitivity is not as good as the PCT-V; therefore, we suggest that this kit is suitable for clinical use.

THCH as electron donor in controlled-release system for procalcitonin analysis based on Bi2Sn2O7 photoanode

A split-type photoelectrochemical (PEC) sensor for procalcitonin (PCT) detection was successfully prepared. This split-type sensor adopted controlled-release strategy, which separated the two processes of antigen-antibody specific recognition and photoelectric conversion, so that the two processes can be performed independently. In addition, CdS sensitized Bi2Sn2O7 is combined for the first time to form a heterojunction as the matrix to provide the basic PEC response, which could effectively absorb visible-light, and reduced electron-hole pair recombination, ensured the stability of the sensor. Distinctly important, the skillfully process was performed in a 96-well plate where the specific reaction was completed proceeded between antigen and antibody. For improving sensitivity of the sensor, acetylcholinesterase (ACHE) connected to SiO2 nanospheres (SiO2 NSs) modified by second antibody (Ab2-ACHE@SiO2 NSs) was designed, the thiocholine (THCH) can be released when acetylthiocholine iodide (ATCH) exists, and the THCH as an electron donor could enhance PEC response. The proposed PEC immunoassay with high-performance photosensitive materials, and the smart electron donor released strategy have a wide detection liner range from 0.0005 to 100 ng/mL with a low detection limit of 0.17 pg/mL, also provide great clinical diagnostic potential for other target proteins.

A signal-off electrochemical sensing platform based on Fe3S4-Pd and pineal mesoporous bioactive glass for procalcitonin detection

Herein, a sandwich-type electrochemical (EC) immunosensor is proposed based on a special signal-off mode for the sensitive detection of procalcitonin (PCT) by utilizing Fe3S4 loaded with Pd nanoparticles (Fe3S4-Pd) as a signal indicator and matrix and functionalized pineal mesoporous bioactive glass (PBG) as the label for signal amplification. Fe3S4-Pd not only shows excellent electrocatalytic activity for the H2O2 redox reaction but is also firmly immobilized on a magnetic glassy carbon electrode due to its excellent magnetic properties; because of the above features, this immunosensor exhibits excellent sensitivity and stability, respectively. Glutaraldehyde is used as a cross-linking agent to bond the secondary antibodies (Ab2) with PBG. It is worth mentioning that the electron transfer rate between the electrolyte and electrode is decreased significantly by PBG-Ab2; thus, a sensitive variation in the current signal is observed, and a further improvement in the sensitivity of the immunosensor is realized. More importantly, the proposed signal-off sensing system has a wide linear detection range of 500 fg/mL to 50 ng/mL for PCT and a low detection limit of 130 fg/mL, which promotes it as a promising detection method for the sensitive detection of other biomarkers.

Common-path interferometric label-free protein sensing with resonant dielectric nanostructures

Research toward photonic biosensors for point-of-care applications and personalized medicine is driven by the need for high-sensitivity, low-cost, and reliable technology. Among the most sensitive modalities, interferometry offers particularly high performance, but typically lacks the required operational simplicity and robustness. Here, we introduce a common-path interferometric sensor based on guided-mode resonances to combine high performance with inherent stability. The sensor exploits the simultaneous excitation of two orthogonally polarized modes, and detects the relative phase change caused by biomolecular binding on the sensor surface. The wide dynamic range of the sensor, which is essential for fabrication and angle tolerance, as well as versatility, is controlled by integrating multiple, tuned structures in the field of view. This approach circumvents the trade-off between sensitivity and dynamic range, typical of other phase-sensitive modalities, without increasing complexity. Our sensor enables the challenging label-free detection of procalcitonin, a small protein (13 kDa) and biomarker for infection, at the clinically relevant concentration of 1 pg mL−1, with a signal-to-noise ratio of 35. This result indicates the utility for an exemplary application in antibiotic guidance, and opens possibilities for detecting further clinically or environmentally relevant small molecules with an intrinsically simple and robust sensing modality.

Simultaneous electrical detection of IL-6 and PCT using a microfluidic biochip platform.

Sepsis, a life-threatening organ dysfunction caused by a dysregulated host response, leads the U.S in both mortality rate and cost of treatment. Sepsis treatment protocols currently rely on broad and non-specific parameters like heart and respiration rate, and temperature; however, studies show that biomarkers Interlukin-6 (IL-6) and Procalcitonin (PCT) correlate to sepsis progression and response to treatment. Prior work also suggests that using multi-parameter predictive analytics with biomarkers and clinical information can inform treatment to improve outcome. A point-of-care (POC) platform that provides information for multiple biomarkers can aid in the diagnosis and prognosis of potentially septic patients. Using impedance cytometry, microbead immunoassays, and biotin-streptavidin binding, we report a microfluidic POC system that correlates microbead capture to IL-6 and PCT concentrations. A multiplexed microbead immunoassay is developed and validated for simultaneous detection of both IL-6 and PCT from human plasma samples. Using the POC platform, we quantified plasma samples containing healthy, medium (~103pg/ml) and high (~105pg/ml) IL-6 and PCT concentrations with various levels of significance (P < 0.05-P <0.00001) and validated the concept of this device as a POC platform for sepsis biomarkers.

A dual-mode PCT electrochemical immunosensor with CuCo2S4 bimetallic sulfides as enhancer

A method for the detection of procalcitonin (PCT) with improved accuracy is urgently needed. A dual-mode electrochemical immunosensor with CuCo2S4–Au bimetallic sulfides as enhancer for accurate detection of PCT was fabricated in this work. The immunosensor not only displays a heavy square wave voltammetry (SWV) signal due to the electron transfer of Cu2+ and Cu+ but not the addition of electron mediators. But also presents high electrocatalytic activity towards H2O2 redox reactions and enhances the detection sensitivity of the amperometric i-t curve (i-t). The introduction of Au nanoparticles, not only improves the conductivity but also has synergistic effects between Au NPs and CuCo2S4, which promote the detection sensitivity by SWV and i-t. To firmly immobilize antibodies, electrolytic gold was used as the matrix for the immunosensor. Based on a CuCo2S4–Au dual-signal indicator and electrolytic gold as the matrix, the developed immunosensor for PCT detection in this study demonstrates a wide linear response (0.0001–50 ng/mL) and a low detection limit (SWV: 82.6 fg/mL and i-t: 95.4 fg/mL). Additionally, the fabricated immunosensor exhibited an outstanding analytical approach for PCT and broad application for other biomarkers in clinical diagnosis and treatment.

Validated electrochemical immunosensor for ultra-sensitive procalcitonin detection: Carbon electrode modified with gold nanoparticles functionalized sulfur doped MXene as sensor platform and carboxylated graphitic carbon nitride as signal amplification

Septicemia, also known as sepsis, refers to a systemic inflammatory response syndrome and becomes the dominant reason of mortality for seriously diseases. Procalcitonin (PCT), the peptide precursor of the hormones, is a key biomarker of septicemia in the diagnosis and detection of bacterial inflammation. In this study, an ultra-sensitive sandwich type electrochemical immunosensor for PCT detection was constructed. Firstly, delaminated sulfur-doped MXene (d-S-Ti3C2TX MXene) modified glassy carbon electrode (GCE) including gold nanoparticles (AuNPs) was utilized as immunosensor platform to increase the amount of PCT antibody1 (Ab1). After that, carboxylated graphitic carbon nitride (c-g-C3N4) was used to label PCT Ab2 as signal amplification. The structure of electrochemical immunosensor was highlighted by x-ray diffraction (XRD) method, scanning electron microscope (SEM), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), fourier transform infrared spectroscopy (FTIR), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). Herein, c-g-C3N4 not only has excellent catalytic activity toward H2O2 for signal amplification, but also can be directly utilized as redox probe. The analytical results have revealed that 0.01 - 1.0 pg mL-1 and 2.0 fg mL-1 were found as linearity range and limit of detection (LOD). Furthermore, the validated electrochemical immunosensor was examined in terms of stability, repeatability, reproducibility and reusability. Finally, the immunosensor was applied to plasma samples having high recovery.

Enzyme-free colorimetric immunoassay for procalcitonin based on MgFe2O4 sacrificial probe with the Prussian blue production

An enzyme-free immunosorbent assay using MgFe2O4 modified with cysteine (MgFe2O4@Cys) as sacrificial probe for the detection of procalcitonin (PCT) was developed. MgFe2O4@Cys was linked with second antibody of PCT (Ab2) by cysteine amino group and released Fe3+ under acidic conditions. Taking advantage of Fe3+ and [Fe(CN)6]4− generating soluble Prussian blue (PB), a novel method of PCT determination was established by measuring the absorbance of the generated PB. Different from the traditional immunosensor detection mode, the enzyme-free colorimetric immunosensor in this work can not only avoid the interference of nano-enzymes or enzymes, but also has the advantages of rapid detection, low cost, high selectivity and sensitivity. Therefore, the developed immunosensor for PCT detection exhibited a wide linear response (0.0001–50 ng/mL) and a low detection limit (44.9 fg/mL). Additionally, the immunosensor exhibits satisfactory performance in human serum testing, which indicated its good application value in clinical diagnoses.

Procalcitonin and Bacterial Infections in the Human Body

Procalcitonin (PCT), a member of the calcitonin (CT) superfamily, is a 116 amino acid, 13 kilodalton precursor protein produced in humans in the parafollicular cells of the thyroid as well as the neuroendocrine cells of the lungs and intestines of healthy individuals. PCT is coded for in the Calc‐I gene, located on chromosome 11. PCT is the precursor to the regulatory protein calcitonin but may have its own, separate role in the human body’s response to bacterial infection. There is a positive correlation between the concentration of PCT in the blood and the severity of a bacterial infection, making PCT an acute phase reactant. Under normal conditions, PCT undergoes proteolytic cleavage in the thyroid and is converted into CT, which then leaves the thyroid and enters the bloodstream; however, under inflammatory conditions, PCT is not cleaved and enters the bloodstream in a three‐section state comprising an amino terminus, immature calcitonin, and calcitonin carboxyl‐terminus peptide. Additionally, under inflammatory conditions, PCT is produced in other locations besides the parafollicular cells of the thyroid and the neuroendocrine cells of the lungs and intestines due to an increase in the expression of the Calc‐I gene. The reason for this increase may be related to potential anti‐inflammatory characteristics of PCT, including an ability to signal a reduction in the production of pro‐inflammatory proteins such as tumor necrosis factor‐alpha and interleukin 1‐beta. Furthermore, PCT in a specific concentration has been shown to reduce the reactivity of lipopolysaccharide (LPS) in gram‐negative bacteria. These properties of PCT have many potential applications in the medical field that are currently being studied or used. For example, detection of PCT in the blood can be used to determine if an infection is viral or bacterial or to evaluate the severity of infection in patients with sepsis. The determination of the pathogen allows for the correct course of appropriate treatment, potentially preventing the overprescription and overuse of antibiotics, a critical concern with the continued rise of bacterial antibiotic resistance. Additionally, as patients recover from a systemic bacterial infection, monitoring the level of PCT allows physicians to determine when the course of antibiotics may be stopped, once again minimizing antibiotic overuse. The Walton High School SMART Team has designed a 3D model of procalcitonin to investigate the relationship between procalcitonin’s structure and its function.Support or Funding InformationMSOE Center for Biomolecular Modeling

Label-free electrochemical immunosensor with palladium nanoparticles functionalized MoS2/NiCo heterostructures for sensitive procalcitonin detection

An ultrasensitive label-free electrochemical immunosensor using MoS2/NiCo heterostructures as an efficient signal enhancer was proposed for sensitive detection of procalcitonin. The MoS2/NiCo heterostructures were synthesized by thermally depositing MoS2 on NiCo MOFs nanocubes, which were then functionalized with in situ grown palladium nanoparticles (Pd NPs) for electrochemically catalyze the reduction of hydrogen peroxide. The presence of MoS2/NiCo heterostructures greatly enhanced the electrocatalytic activity of Pd NPs, thus the Pd NPs@MoS2/NiCo modified electrode showed amplified response to hydrogen peroxide. The large specific surface of Pd NPs@MoS2/NiCo greatly improved the loading of antibody for preparation of immunosensor. Upon the incubation of the immunosensor with target procalcitonin, the electron transfer impendence increased, and thus the chronoamperometric response decreased, leading to a highly sensitive immunosensing method for detection of procalcitonin. The proposed method showed a linear range of 0.001–50 ng/mL with a detection limit of 0.36 pg/mL (S/N = 3). It possessed excellent accuracy and good practicality for diagnostics of PCT related diseases, and could be extended for development of other immunosensors for biomarkers detection.

Triple Amplification of 3,4,9,10-Perylenetetracarboxylic Acid by Co2+-Based Metal-Organic Frameworks and Silver-Cysteine and Its Potential Application for Ultrasensitive Assay of Procalcitonin.

In this work, a triple-amplified biosensor with a bioactivity-maintained peculiarity was constructed for quantitative procalcitonin (PCT) detection. As everyone knows, a strong electrochemiluminescence (ECL) signal is the premise to ensure high sensitivity for trace target detection. Hence, a valid tactic was developed to achieve signal amplification of luminophor by using Co2+-based metal-organic frameworks (ZIF-67) and silver-cysteine (AgCys). The ZIF-67 particles, which have more atomically dispersed Co2+, could play the role of a co-reaction accelerator to catalyze S2O82- to generate abundant Co3+ and sulfate radical anions (SO4•-). Afterward, a mass of Co3+ was reduced to more hydroxyl radicals (OH•) by H2O, thus ulteriorly reducing S2O82- to generate more SO4•-. Remarkably, S2O82- was reduced to SO4•- continuously with the recycling of Co2+ and Co3+, which realized an effective signal amplification. Meanwhile, the AgCys complex with superior catalysis and biocompatibility was prepared to further improve the ECL signal and maintain the bioactivity of the biomolecule. Furthermore, HWRGWVC, a heptapeptide that was used for combining the Fc fragments of an antibody by Au-S bonding to achieve the fixed point fixation, could not only maintain bioactivity of an antibody but also improved its incubation efficiency, thus further enhancing biosensor sensitivity. Under optimum conditions, the proposed biosensor realized highly sensitive assay for PCT with a wide dynamic range from 10 fg/mL to 100 ng/mL and a detection limit as low as 3.67 fg/mL. With superior stability, selectivity, and repeatability, the prepared biosensor revealed immense potential application of ultrasensitive assay for PCT in human serum.

Quench-Type Electrochemiluminescence Immunosensor Based on Resonance Energy Transfer from Carbon Nanotubes and Au-Nanoparticles-Enhanced g-C3N4 to CuO@Polydopamine for Procalcitonin Detection.

A new type of sandwich electrochemiluminescence (ECL) immunosensor dependent on ECL resonance energy transfer (ECL-RET) to achieve sensitive detection of procalcitonin (PCT) has been designed. In brief, carbon nanotubes (CNT) and Au-nanoparticles-functionalized graphitic carbon nitride (g-C3N4-CNT@Au) and CuO nanospheres covered with polydopamine (PDA) layer (CuO@PDA) were synthesized and applied as ECL donor and receptor, respectively. g-C3N4-CNT nanomaterials were in situ prepared on the basis of π-π conjugation, and the CNT content in the composite were optimized to achieve a strong and stable ECL signal. At the same time, Au nanoparticles were used to functionalize g-C3N4-CNT to further increase the ECL intensity and the loading amount of primary antibody (Ab1). Moreover, CuO@PDA was first used to successfully quench the ECL signal of g-C3N4-CNT@Au. Under the optimum experimental conditions, the linear detection range for PCT concentration was within 0.0001-10 ng mL-1 and the detection limit was 25.7 fg mL-1 (S/N = 3). Considering prominent specificity, reproducibility, and stability, the prepared immunosensor was used to assess recovery rate of PCT in human serum according to the standard addition method and the result was satisfactory. In addition, it is worth mentioning that a novel ECL-RET pair of g-C3N4-CNT@Au (donor)/CuO@PDA (acceptor) was first developed, which offered an effective analytical tool for sensitive detection of biomarkers in early disease diagnostics.

Ultrasensitive photoelectrochemical immunosensor for procalcitonin detection with porous nanoarray BiVO4/CuxS platform as advanced signal amplification under anodic bias

A new, porous nanoarray BiVO4/CuxS (PN-BiVO4/CuxS) platform as an advanced signal amplification strategy under anodic bias on the process of electrochemical catalysis assisted self-enhancing based photoelectrochemical (ECASE-based PEC) without electron donors was established for ultrasensitive procalcitonin (PCT) detection. The system operated upon that the PN-BiVO4/CuxS electrode could enhance separation of e−/h+ pairs under illumination of visible-light because the energy levels between BiVO4 and CuxS matched well. Afterwards, the photoexcited electrons could shift to working electrode as output signal, while the photoexcited holes could oxidize water under anodic bias to produce hydrogen peroxide (H2O2) that was subsequently reduced by CuxS, which resulted in significantly enhanced photocurrent intensity by electrochemical process. To further enhance the sensitivity of PEC immunosensor, amino-modified polystyrene (PS) nanoparticles act as labels for immobilizing secondary antibodies (Ab2) to form PS@Ab2 conjugates for construction of sandwich-type immunosensor on the basis of ECASE-based PEC strategy. The designed PEC immunosensor exhibited a linear concentration range from 50 fg mL-1 to 100 ng mL-1, with a low detection limit of 17.3 fg/mL (S/N = 3) for PCT, and achieved good selectivity, acceptable stability, and high sensitivity. This work first conducted the ECASE-based PEC system, and we believed it will provide a new perspective for developing innovative signal amplification toward detection of other biomarker in the future.

Antigen down format photoelectrochemical analysis supported by fullerene functionalized Sn3O4.

Herein, a smart competitive-type photoelectrochemical (PEC) sensor based on an antigen-down (Ag-down) format for procalcitonin (PCT) detection is proposed. A fullerene sensitized flower-like Sn3O4 nano-structure is used as the photoactive platform, and FeS2 is labeled on the secondary antibody as a signal adjusting element. The sensor exhibits excellent sensitivity and great stability.

Comparison of the clinical application values of PCT, hs-CRP and SAA detection in the early diagnosis of sepsis.

Objectives:To investigate the clinical application values of procalcitonin (PCT), high-sensitivity C-reactive protein (hs-CRP) and serum amyloid A (SAA) in the early diagnosis of sepsis.Methods:In this retrospective analysis, 36 patients admitted to Liaocheng People’s Hospital were selected from May 2018 to July 2019. According to infectious disease diagnostic criteria, 17 patients were confirmed to have sepsis (observation group), and 19 patients were determined to be nonseptic (control group). The levels of PCT, CRP and SAA of patients were detected on admission, and the clinical application values of PCT, CRP and SAA for sepsis were compared.Results:Seventeen patients were included in the observation group, including 9 males and 8 females, with an average age of 52.18 ± 9.49 years; 19 patients were included in the control group, including 12 males and 7 females, with an average age of 51.53 ± 8.50 years. On admission, there were significant differences in white blood cell (WBC) count (t = 5.134), neutrophil count (t = 3.143), lymphocyte count (t = 2.510), PCT (t = 9.250), hs-CRP (t = 2.947) and SAA (t = 11.360) between the observation group and the control group, and the differences were statistically significant. For the comparison of clinical application values: the sensitivity of PCT, hs-CRP and SAA was 78.95%, 52.17% and 50.00%, respectively; the specificity of PCT, hs-CRP and SAA was 88.24%, 61.54% and 37.50%, respectively; the area under the ROC curve (AUC) of PCT, hs-CRP and SAA was 0.920, 0.684 and 0.870, respectively; the logistic regression coefficient of PCT, hs-CRP and SAA was -0.577, -0.028 and -0.009, respectively; and the 95% confidence interval (CI) of PCT, hs-CRP and SAA was 0.779-0.985, 0.508-0.828 and 0.716-0.958, respectively.Conclusion:Compared with hs-CRP and SAA, PCT had a higher clinical application value for sepsis, and PCT could be used as a reliable index for the early diagnosis of sepsis.

Prediction of premature rupture of membranes via simultaneous detection of procalcitonin and interleukin-6 by a SERS-based immunochromatographic assay

The rapid and sensitive detection strip with two test lines was developed based on SERS for the early screening of PROM.