An electrochemical immunosensor for the detection of carcinoembryonic antigen based on Au/g-C3N4 NSs-modified electrode and CuCo/CNC as signal tag

Dual-mode detection of α-fetoprotein using the photothermal effect and peroxidase-like activity of Au@Cu/Cu2O-rGO

α-Fetoprotein (AFP) is widely recognized as an important marker for monitoring hepatocellular carcinoma (HCC), and its monitoring using two different transduction mechanisms is an effective way to avoid the risk of false positives or false negatives. In this paper, Au@Cu/Cu2O-rGO was used as a photothermal converter as well as an actuator to promote the decomposition of hydrogen peroxide (H2O2), which was further designed as a probe for dual-mode detection to quantitatively assess AFP. The composite nanomaterials possessed photothermal conversion efficiencies (η) of up to 54.9 % and catalytically generated signals up to 1.6 times greater, relative to a single material. Based on the generated temperature and current signals, AFP has been sensitively detected in the range of 0.01-100 ng/mL, with limits of detection (LOD) of 5.62 pg/mL and 1.23 pg/mL, respectively. The dual-mode assay combines portability with high accuracy for the detection of human health systems.

Enhanced-electrochemiluminescence biosensor for detecting miRNA-21 based on a CuO-mediated click reaction and catalytic hairpin self-assembly

MicroRNAs (miRNAs) are closely associated with cancer and have been considered cancer biomarkers. Herein, we propose an electrochemiluminescence (ECL) biosensor for detecting miRNA-21 based on target-induced catalytic hairpin self-assembly (CHA) and CuO-mediated azide-alkyne cycloaddition. Two hairpin DNAs were employed: one was immobilized on magnetic beads (HP2) and another was labeled with CuO (HP1-CuO). HP1 and HP2 formed a duplex through CHA induced by miRNA-21, resulting in the immobilization of CuO on magnetic beads and in the recycling of miRNA-21. After magnetic separation, CuO was treated with hydrochloric acid to release Cu2+, which concentration is quantitatively proportional to the target concentration. Subsequently, Cu2+ was reduced to Cu+, which catalyzed the click reaction between Fc-C CH and SH-DNA-N3+ immobilized on a Au/g-C3N4 modified electrode. Thus, the ECL of Au/g-C3N4 was quenched by Fc, and miRNA-21 was indirectly detected through a change in ECL intensity. Benefiting from the amplification effect of CuO nanoparticle loading, CHA-based target recycling, and the catalytic effect of click reaction, the proposed ECL biosensor showed high sensitivity. Experimental results indicate that the ECL biosensor proposed for detecting miRNA-21 exhibits a wide linear range from 1 fM to 1 nM and a low detection limit of 0.26 fM (3σ/S). Furthermore, the ECL sensor was capable of measuring miRNA-21 in real serum with high selectivity, indicating its notable applicable potential in biomedicine and clinical diagnosis.

Electrochemical Nanobiosensor of Ionic Liquid Functionalized MoO3-rGO for Sensitive Detection of Carcinoembryonic Antigen

Early diagnosis of cancer can be achieved by detecting associated biomarkers before the appearance of symptoms. Herein, we have developed an electrochemical immunosensor of ionic liquid tailored to molybdenum trioxide-reduced graphene oxide (MoO3-rGO-IL) nanocomposite to detect carcinoembryonic antigen (CEA), a cancer biomarker. The MoO3-rGO-IL nanocomposite has been synthesized in situ via the hydrothermal method. The functionalization of 1-butyl-3-methylimidazolium tetrafluoroborate IL with MoO3-rGO synergistically improves the electrochemical and surface properties of the nanocomposite. The characterization studies revealed that the MoO3-rGO-IL nanocomposite is a highly appropriate material for the construction of immunosensors. The material exhibits exceptional electrical conductivity, surface properties, stability, and a large electrochemical effective surface area (13.77×10-2 cm2) making it ideal for fabricating immunosensors. The quantitative outcome showed that the developed immunosensor (BSA/anti-CEA/MoO3-rGO-IL/GCE) possesses excellent sensitivity, broad linearity from 25 fg mL-1 to 100 ng mL-1, and a low detection limit of 1.19 fg mL-1. Moreover, the remarkable selectivity, repeatability, and efficiency of detecting CEA in serum specimens demonstrated the feasibility of the immunosensor. Thus, the projected electrochemical immunosensor can potentially be utilized for the quantification of CEA in clinical specimens.

A label-free electrochemical immunosensor based on 11-mercaptoundecanoic acid grafted chitosan and poly(N-methylaniline) for the detection of carcinoembryonic antigen

Carcinoembryonic antigen (CEA) is a cancer marker used for monitoring cancer treatment. Herein, a label-free electrochemical immunosensor for determining CEA concentration composed of the thiolated chitosan (tCHI) and the doped poly(N-methylaniline) (dPNMA) is proposed. The tCHI served as a support matrix for the immobilization of CEA antibodies (anti-CEA) and was prepared by using 11-mercaptoundecanoic acid (MUA) as a grafting agent on chitosan (CHI). The excellent electrical conductivity of the dPNMA was utilized as an electron transfer layer for the proposed immunosensor. The successful preparation of the tCHI was confirmed by the attenuated-total reflection Fourier transform spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Cyclic voltammetry (CV), differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS) were used to illustrate the performance of the proposed immunosensor. The determination of CEA concentration was relied on the decrease in the DPV current response with increasing CEA concentration from the creation of the antigen-antibody immunocomplex. The proposed immunosensor demonstrated a broad concentration range of 0.01 to 30 ng mL^-1 with a low limit of detection (LOD) of 0.01 ng mL^-1. In addition, the present sensor exhibited excellent selectivity, reproducibility, and long-term stability, suggesting its potential use to determine CEA in clinical immunoassay.

An ultrasensitive electrochemical immunosensor for carcinoembryonic antigen detection based on two-dimensional PtPd/Cu-TCPP(Fe) nanocomposites

Establishing an effective signal amplification strategy is the key to achieving sensitive detection of analytes by electrochemical immunoassay. In this work, a novel sandwich-type electrochemical immunosensor with dual-signal amplification was successfully constructed using PtPd/Cu-TCPP(Fe) as the sensing platform and mesoporous silicon dioxide as the signal amplifier. Firstly, two-dimensional wrinkled Cu-TCPP(Fe) nanomaterials loaded with PtPd nanoparticles have strong affinity for the immobilization of capture antibodies and can generate excellent electrochemical signals. Meanwhile, the mesoporous silicon dioxide with large steric hindrance was used as signal label to further improve the sensitivity of the immunosensor by increasing the difference of the current response signal. Under optimal experimental conditions, the electrochemical immunosensor exhibited a wide linear detection range from 0.1 pg/mL to 1.0 μg/mL, with a detection limit as low as 0.166 fg/mL. The experimental results showed that the constructed immunosensor has a great application prospect in clinical biomarker detection.

Application Value of Serum TK1 and PCDGF, CYFRA21-1, NSE, and CEA plus Enhanced CT Scan in the Diagnosis of Nonsmall Cell Lung Cancer and Chemotherapy Monitoring

Objective

To assess the application value of serum thymidine kinase 1 (TK1) and PC cell-derived growth factor (PCDGF), cytokeratin 19 fragment 21-1 (CYFRA21-1), neuron-specific enolase (NSE), and carcinoembryonic antigen (CEA) plus enhanced CT scan in the diagnosis of nonsmall cell lung cancer (NSCLC) and chemotherapy monitoring.

Methods

Between April 2019 and April 2021, 30 patients with NSCLC assessed for eligibility treated in our institution were included in the experimental group, and 30 healthy individuals screened out from physical examinations were recruited in the control group. The chemotherapy regimens included gemcitabine plus cisplatin, pemetrexed disodium plus cisplatin, and vinorelbine plus cisplatin. The application value of serum TK1, PCDGF, CYFRA21-1, NSE, CEA, and enhanced CT scan in the diagnosis and chemotherapy monitoring of NSCLC was analyzed.

Results

Before treatment, the eligible patients had significantly higher serum levels of TK1, PCDGF, CYFRA21-1, NSE, and CEA than those of the healthy individuals included (P < 0.05). Clinical efficacy was categorized into good and poor, and the good efficacy included complete response and partial response, with the poor efficacy including stable disease and progressive disease. Patients with good clinical efficacy had lower levels of serum TK1, PCDGF, CYFRA21-1, NSE, and CEA than those with poor efficacy (P < 0.05). Joint detection showed a larger area under the curve (AUC) (0.900; 95%CI, 0.812-0.988), a higher sensitivity, and a superior detection outcome to the stand-alone detection (P < 0.05). Diagnostic results were similar between joint detection and pathological examination (P > 0.05).

Conclusion

The application of serum TK1, PCDGF, CYFRA21-1, NSE, and CEA assay plus enhanced CT scan shows high sensitivity and diagnostic accuracy in the diagnosis and chemotherapy monitoring of nonsmall cell lung cancer and thus provides a diagnostic reference basis.

Graphene-PtPd nanocomposite for low-potential-driven electrochemiluminescent determination of carcinoembryonic antigen using Ru(bpy)32

As well known, the electrochemiluminescence (ECL) of tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)₃²⁺) heavily relies on highly positive or negative triggered voltage, prejudicing the detection toward the bio-molecules. In this work, Ru(bpy)₃²⁺ could generate enhanced and stable ECL at a low potential of 0.05 V (vs. Ag/AgCl) on graphene-PtPd hybrid, attributing to its excellent electrocatalysis from the synergistic effect between Pt and Pd. The obtained low-potential-driven ECL could be quenched by MoS₂ nanoflowers. Based on the quenching effect, a sandwich "signal-off" ECL immunosensor was fabricated to sensitively detect carcinoembryonic antigen (CEA). A linear calibration curve from 1 fg mL^-1 to 1 ng mL^-1 was obtained along with a low detection limit of 0.54 fg mL^-1 (S/N = 3) under optimal conditions. The sensor showed satisfactory specificity, stability, and reproducibility and was successfully applied to determine CEA in actual samples. The recoveries ranged from 98.80 to 100.23%, and the relative standard deviation (RSD) was lower than 5%. Above all, this work explored new materials in low-potential-driven ECL system and provided a reliable sensing strategy for clinical applications.