Quantitative Detection Of C-reactive Protein Research Articles

Multiplex Assay of Cytokines with Tunable Detection Ranges for the Precise Diagnosis of Breast Cancer.

Precise profiling of the cytokine panel consisting of different levels of cytokines can provide personalized information about several diseases at certain stages. In this study, we have designed and fabricated an "all-in-one" diagnostic tool kit to bioassay multiple inflammatory cytokines ranging from picograms per milliliter to μg/mL in a small cytokine panel. Taking advantage of the kit fabricated by the DNA-encoded assembly of nanocatalysts in dynamic regulation and signal amplification, we have demonstrated the multiplex, visual, and quantitative detection of C-reactive protein (CRP), procalcitonin (PCT), and interleukin-6 (IL-6) with limits of detection of 1.6 ng/mL (61.54 pM), 20 pg/mL (1.57 pM), and 4 pg/mL (0.19 pM), respectively. This diagnostic tool kit can work well with commercial kits for detecting serum cytokines from breast cancer patients treated with immunotherapies. Furthermore, a small cytokine panel composed of CRP, PCT, and IL-6 is revealed to be significantly heterogeneous in each patient and highly dynamic for different treatment courses, showing promise as a panel of quantitative biomarker candidates for individual treatments. So, our work may provide a versatile diagnostic tool kit for the visual detection of clinical biomarkers with an adjustable broad detection range.

One-Component Dual-Readout Aggregation-Induced Emission Nanobeads for Qualitative and Quantitative Detection of C-Reactive Protein at the Point of Care.

Fluorescent lateral flow immunoassay (LFA) systems are versatile tools for sensitive and quantitative detection of disease markers at the point of care. However, traditional fluorescent nanoparticle-based lateral flow immunoassays are not visible under room light, necessitate an additional fluorescent reader, and lack flexibility for different application scenarios. Herein, we report a dual-readout LFA system for the rapid and sensitive detection of C-reactive protein (CRP) in clinical samples. The system relied on the aggregation-induced emission nanobeads (AIENBs) encapsulated with red AIE luminogen, which possesses both highly fluorescent and colorimetric properties. The AIENB-based LFA in the naked-eye mode was able to qualitatively detect CRP levels as low as 8.0 mg/L, while in the fluorescent mode, it was able to quantitatively measure high-sensitivity CRP (hs-CRP) with a limit of detection of 0.16 mg/L. The AIENB-based LFA system also showed a good correlation with the clinically used immunoturbidimetric method for CRP and hs-CRP detection in human plasma. This dual-modal AIENB-based LFA system offers the convenience of colorimetric testing and highly sensitive and quantitative detection of disease biomarkers and medical diagnostics in various scenarios.

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

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

Quantitative detection of C-reactive protein in human saliva using an electrochemical lateral flow device

Lateral flow devices (LFDs) allow for low-cost decentralized testing with a short time to result and are therefore an indispensable tool for point-of-care diagnostics. Here, we report on a novel LFD with electrochemical readout for the quantitative detection of C-reactive protein (CRP), a known biomarker for inflammation, in filtered human saliva and demonstrate the possibility of simultaneous multichannel measurements. The detection of CRP is enabled by a sandwich assay with target specific capture antibodies immobilized in a nitrocellulose membrane and target specific detection antibodies conjugated to an enzyme label. The subsequent enzymatic reaction leads to a product, which can be oxidized by an electrochemical sensor placed on top of the LFD strip and produce a concentration dependent and analyte specific electrical current. To optimize the system, single channel sensors were used to investigate different conjugate compositions and loads for their effect on assay performance. That way, limits of detection (LOD) of 3 and 25 ng/mL were achieved in buffer and filtered saliva, respectively. Then, a single sensor with four distinct channels was introduced for the testing of simultaneous multichannel measurements. There, the CRP dedicated channel showed a typical concentration dependency (with LODs of 13 and 55 ng/mL in buffer and filtered saliva, respectively), while the control channel expectedly produced elevated signals across all CRP concentrations. The signals corresponding to the other two channels (zeros) remained low with no indication of crosstalk, showing the ability to measure multiple locations on the LFD simultaneously and thus, paving the way for multiplexing.

Fluorescent fullerene nanoparticle-based lateral flow immunochromatographic assay for rapid quantitative detection of C-reactive protein

A fluorescent fullerene nanoparticle (NP)-based lateral flow immunochromatographic assay (LFIA) was developed for the rapid and quantitative detection of C-reactive protein (CRP) in serum. The polyclonal CRP-antibody-conjugated fullerene NPs were simply prepared by 1-ethyl-3-(3-dimethyllaminopropyl)-carbodiimide hydrochloride coupling after carboxylation of fluorescent fullerene NPs. By applying the CRP-antibody-conjugated fullerene NPs to a lateral flow test strip, quantitative analysis of CRP in serum was possible at a concentration range of 0.1–10 ng/ml within 15 min. We anticipate that this novel fluorescent fullerene NP-based LFIA can be useful for the rapid and accurate sensing of biological and chemical species, contributing to the disease diagnosis and prognosis, environmental monitoring, and food safety.

An Enzyme-Linked Immunosorbent Assay for C-Reactive Protein Based on Gold Nanoparticles@Metal Porphyrin Porous Compound.

In this paper, an enzyme-linked immunosorbent assay (ELISA) using gold nanoparticles/metal porphyrin porous compound (Au NPs@PAF-40-Fe) as a marker was developed. Quantitative detection of C-reactive protein (CRP) was achieved by UV-visible spectrophotometry under optimal conditions. The sensor has a good linear relationship in the range of 0.05-2000 ng/mL. The lower limit of detection was 0.017 ng/mL (S/N = 3), the linear correlation coefficient was 0.9921, and the average recovery was 100.74%. The ELISA has good selectivity and provides a sensitive way for detection of CRP.

Synthesis of highly stable CuInZnS/ZnS//ZnS quantum dots with thick shell and its application to quantitative immunoassay

In this paper, CuInZnxS2+x (CIZS, x = 1) have been used as cadmium-free core materials to synthesize CIZS-based core/shell quantum dots (QDs). By introducing extra Zn precursor to CIZS cores, two-time separate shell growth process, and continuous long time replenishment of shell precursor, cation exchange between Cu and Zn ions during the growth of the ZnS shell has been greatly reduced and as large as 7.8 ± 1.2 nm CIZS/ZnS//ZnS with an average of 3.1 nm shell were synthesized successfully. Such thick shell CIZS/ZnS//ZnS core/shell QDs had high stability and high quantum yields (77%). Compared with the thin shell CIZS/ZnS QDs, the thick shell CIZS/ZnS//ZnS QDs still showed excellent PLQY (up to 58%) and stability in different environment after transfer to aqueous solution. We adopted the thick shell cadmium-free QDs as fluorescence label into lateral flow immunoassay for quantitative detection of C-reactive protein, and the limit of detection was 5.8 ng/mL, which was almost as low as that of cadmium-based quantum dot lateral flow test strip. Therefore, this kind of thick shell CIZS/ZnS//ZnS QDs can be used as probes for ultra-sensitive detection, and the further development of this kind of QDs has immense potential for future convenient and cost-effective in vitro cadmium-free nano-medical diagnostic kits.

SERS-based lateral flow assay for quantitative detection of C-reactive protein as an early bio-indicator of a radiation-induced inflammatory response in nonhuman primates.

In accidental irradiation situations, rapid in-field evaluation of acute radiation syndrome is critical for effective triage and timely medical treatment of irradiated individuals. A surface-enhanced Raman scattering (SERS)-based lateral flow assay was developed for the quantitative detection of C-reactive protein (CRP) as an early bio-indicator of a radiation-induced inflammatory response in nonhuman primates. Raman reporter-embedded gold-core silver-shell nanoparticles with built-in hot spots were synthesized and conjugated with a CRP detection antibody to serve as SERS tags in the lateral flow assay. The proposed SERS-based lateral flow assay can rapidly detect CRP with a limit of detection of 0.01 ng mL-1 and quantitative analysis ability. Furthermore, the assay was applied to evaluate the CRP levels in plasma samples of irradiated nonhuman primates at 0 to 80 h after exposure to sublethal (4 Gy) and lethal (8 Gy) doses of total body irradiation (n = 3 animals per group). The plasma CRP levels increase rapidly within few hours after irradiation. The CRP level peaks are observed at 12 or 24 h after irradiation, with a concentration of 201.30, 386.06 and 475.18 μg mL-1 for the 4 Gy irradiated animals and 197.14, 69.52 and 358.03 μg mL-1 for the 8 Gy irradiated animals. The results indicate the potential application of the proposed SERS-based lateral flow assay to serve as a rapid and accurate point-of-care biodosimetry assay for the quantitative detection of bio-indicators to triage irradiated individuals in the field of a radiation accident.

A pressure-based bioassay for the rapid, portable and quantitative detection of C-reactive protein.

A portable method for the rapid detection of the disease biomarker C-reactive protein (CRP) with a hand-held pressuremeter was developed. The method allows an ultrasensitive quantitation of CRP within the entire clinical range. The pressure-based method could facilitate CRP measurements in point-of-care testing (POCT) scenarios, such as clinical offices, emergency departments, and community service centers.

Rapid and quantitative detection of C-reactive protein based on quantum dots and immunofiltration assay.

Convenient and rapid immunofiltration assays (IFAs) enable on-site “yes” or “no” determination of disease markers. However, traditional IFAs are commonly qualitative or semi-quantitative and are very limited for the efficient testing of samples in field diagnostics. Here, we overcome these limitations by developing a quantum dots (QDs)-based fluorescent IFA for the quantitative detection of C-reactive proteins (CRP). CRP, the well-known diagnostic marker for acute viral and bacterial infections, was used as a model analyte to demonstrate performance and sensitivity of our developed QDs-based IFA. QDs capped with both polyethylene glycol (PEG) and glutathione were used as fluorescent labels for our IFAs. The presence of the surface PEG layer, which reduced the non-specific protein interactions, in conjunction with the inherent optical properties of QDs, resulted in lower background signal, increased sensitivity, and ability to detect CRP down to 0.79 mg/L with only 5 µL serum sample. In addition, the developed assay is simple, fast and can quantitatively detect CRP with a detection limit up to 200 mg/L. Clinical test results of our QD-based IFA are well correlated with the traditional latex enhance immune-agglutination aggregation. The proposed QD-based fluorescent IFA is very promising, and potentially will be adopted for multiplexed immunoassay and in field point-of-care test.

Rapid and quantitative detection of C-reactive protein using quantum dots and immunochromatographic test strips.

BackgroundRapid immunochromatographic tests can detect disease markers in 10–15 minutes, which facilitates clinical diagnosis and treatment programs. However, most immunochromatographic tests employ gold nanoparticles as reporters, and these have only moderate sensitivity and act as qualitative methods for analyzing high biomarker concentrations.MethodsIn this study, we introduce quantum dots (QDs) as fluorescent probes and immunochromatographic strips to develop quantitative fluorescence point-of-care tests (QF-POCT) to analyze C-reactive protein (CRP) levels. Goat anti-rabbit IgG and rabbit IgG were used as control antibodies, and mouse monoclonal CRP antibody pairs were used for disease marker detection. One monoclonal CRP antibody was conjugated with QDs and served as a signal antibody, and the other monoclonal CRP antibody was dispensed onto the nitrocellulose membrane and served as a capturing antibody. In the presence of CRP, the fluorescence intensity of the monoclonal antibody-CRP-monoclonal antibody sandwich complex captured on the nitrocellulose membrane was determined using the fluorescence strip reader.ResultsQF-POCT assays could quantitatively analyze the concentration of CRP in 15 minutes had a detection limit of 0.25 mg/L, and had a wide detection linearity range (0.5–300 mg/L). The intra-assay and interassay coefficients of variation were 8.95% and 9.86% at 0.5 mg/L, 6.47% and 8.66% at 10 mg/L, and 6.81% and 9.10% at 60 mg/L, respectively. In a comparison between clinical samples, the results of this QD-based assay of CRP levels were significantly correlated with those of an Immulite 2000 assay (R=0.993, P<0.001).ConclusionOur results demonstrated that the QD-based immunochromatographic test is a rapid, sensitive, accurate, and quantitative method for the detection of disease biomarkers.

Quantitative detection of C-reactive protein using phosphocholine-labelled enzyme or microspheres

C-reactive protein (CRP) is a positive, acute-phase protein. Plasma levels rise dramatically in response to tissue injury or inflammation and fall rapidly after recovery or treatment. Antibody-based human CRP test systems do not readily detect CRP from other animals due to the species specificity of antibodies directed against human CRP. Thus, generic systems for CRP detection, based solely on the interaction between CRP and phosphocholine (PC), have been developed. PC–bovine serum albumin (PC–BSA) conjugates were produced and either labeled with horseradish peroxidase to facilitate CRP detection in a CRP enzyme-linked sorbent assay (ELSA) or coupled to carboxy-modified microspheres to facilitate the nonenzymatic, turbidimetric detection of CRP. The CRP-ELSA is a competitive assay, where the total assay time is 45 min, the assay sensitivity is 1.06 mg/L CRP, and the dynamic range of the assay is 0–500 mg/L. When PC–BSA conjugate is covalently coupled to carboxylated microspheres, agglutination occurs in the presence of CRP, the extent of which depends on the quantity of CRP present in the sample. Total assay time is 5 min with a dynamic range of 25–500 mg/L. Both assay formats are capable of accurately detecting human CRP and the CRP-ELSA can detect canine CRP as a disease state indicator.