Sensitive Detection Of Carcinoembryonic Antigen Research Articles

Dual quenching ECL strategy based on AgInZnS quantum dots and a new co-reaction promoter oxygen vacancy-modified P5AIn/TiO2 for sensitive CEA detection

A novel electrochemiluminescence (ECL) biosensor for the sensitive detection of carcinoembryonic antigen (CEA) was constructed, utilizing environmentally friendly AgInZnS quantum dots (AgInZnS QDs) and a new co-reaction promoter enriched with oxygen vacancies, namely titanium dioxide/poly(5-aminoindole) (Ov-TiO2/P5AIn). The composite of P5AIn and TiO2 significantly enhanced the reaction rate of AgInZnS QDs with tripropylamine (TPrA). In addition, the presence of oxygen vacancies significantly enhances the electron migration rate of the electrode material, leading to more efficient catalysis of TPrA+ generation and a significant enhancement of ECL signals. Furthermore, a dual-quenching sensing strategy was employed using cuprous oxide-triaminophenol (Cu2O@APF) as the quencher, enabling the biosensor to switch. Through dual quenching of the ECL emission from AgInZnS QDs by Cu2O and APF, the biosensor achieves an extremely low “off” state of the ECL signal. Furthermore, a signal amplification strategy driven by the synergistic action of exonuclease III (ExoIII) and restriction endonuclease (Nt.BbvCI) was designed for a dual-site DNA walker, achieving cyclic amplification of the target signal and ECL signal, thereby turning the signal “on” again. The above mechanism significantly improved the specificity and sensitivity of the biosensor for CEA detection. The prepared biosensor exhibits good stability, selectivity, and sensitivity. The linear range for CEA detection is 5 × 10−14 to 10−8 M, with a detection limit of 16 fM. Additionally, the biosensor demonstrates satisfactory analytical capability for CEA in real blood samples. This strategy provides a reliable new approach for the sensitive detection of CEA and other tumor markers.

A sensitive electrochemiluminescence immunosensor for CEA detection based on the ECL-RET between zinc-based metal–organic frameworks and ZiF-8@PDA

In this study, we developed a new system that using zinc-based metal–organic frameworks NH2-Zn-PTC as the donor and ZiF-8@PDA as the acceptor to achieve highly sensitive detection of carcinoembryonic antigen (CEA), using the fundamentals of electrochemiluminescence resonance energy transfer (ECL-RET). Firstly, the aggregation-induced quenching effect (ACQ) was eliminated by the coordination of PTC in MOF and the ECL signal was improved. Secondly, the ECL signal was further amplified by using Au NPs and amino groups as co-reaction promoters to generate more SO4.−. In addition, the introduction of ZiF-8@PDA as an acceptor and NH2-Zn-PTC as a donor took advantage of the feature of partial overlap of the UV–vis absorption spectrum and ECL emission spectra between the two, thereby effectively initiating the ECL-RET behavior, which improved the detection sensitivity of the sensor. The prepared immunosensor showed good linearity in the concentration range of 10−4 to 80 ng/mL with a detection limit of 18.20 fg/mL. This makes it promising for clinical testing of tumor markers.

A novel signal-on photoelectrochemical immunosensor based on anthocyanin-sensitized poly(indole-5-carboxylic acid) for ultrasensitive detection of CEA

A signal-on photoelectrochemical (PEC) immunosensor for carcinoembryonic antigen (CEA) detection was constructed using anthocyanin (ACN)-sensitized poly(indole-5-carboxylic acid) (P5ICA) nanofibers as the photoactive material. P5ICA is a p-π conjugated cathode photosensitive material with excellent optical and film-forming properties. P5ICA sensitized with ACN prevents hydrolysis of P5ICA, ensures the stability and further improves the base signal of the PEC immunosensor. The sensitive detection of CEA was achieved by introducing the signaling probe TiO2/In2S3 through biotin-avidin protein specific recognition. ACN-sensitized P5ICA and TiO2/In2S3 exhibit the effective matching of energy levels, which facilitates the separation and transfer of photogenerated e-/h+ pairs and achieves the amplification of PEC signals and the improvement of sensor sensitivity. Under optimal conditions, the range of detection for CEA was 0.01–500 ng mL−1 with lower detection limit of 3.3 pg mL−1. The PEC immunosensor has good stability and high detection sensitivity to CEA. This work provides a novel PEC assay platform for monitoring CEA in real serum samples, which has a promising application in the sensitive detection of tumor markers.

Nanochannel-confined platinum nanostructure for enhancement of luminol-dissolved oxygen electrochemiluminescence coupled with gated aptasensor for sensitive detection of carcinoembryonic antigen

Rapid and precise detection of tumor biomarkers in serum is of great significance for early diagnosis, treatment assessment, and recurrence monitoring of cancers. The fabrication of user-friendly electrochemiluminescence (ECL) aptasensors with effective signal amplification is highly desirable. In this study, an ECL aptasensor was developed with luminol-based ternary ECL platform using dissolved oxygen as endogenous co-reactant and nanochannel-confined platinum nanoparticles (PtNPs) as co-reactant promoter, which can realize highly sensitive detection of the tumor biomarker, carcinoembryonic antigen (CEA). On the cost-effective indium tin oxide (ITO) electrode, amino-modified vertically-ordered mesoporous silica film (NH2-VMSF) was easily grown to form high-density nanochannel array with ultrasmall nanochannels. PtNPs were then in-situ synthesized within the nanochannels via electrodeposition. Ternary ECL system was successfully fabricated as confined PtNPs can catalyze the electroreduction of dissolved oxygen at negative potentials as well as electrochemical oxidation of luminol, enhancing the ECL signal of luminol. The recognitive aptamer (Apt) was covalently immobilized on the outer surface of NH2-VMSF, resulting in the fabrication of an aptasensor. In presence of CEA, a decreased ECL signal was obtained as the formed complex on the recognition interface hindered the diffusion of ECL emitter to the supporting electrode. Based on this signal turn-off mode, sensitive detection of CEA was achieved ranged from 10 fg mL−1 to 100 ng mL−1, with a low detection limit (DL, 0.4 fg mL−1). The aptasensor displayed high selectivity and good reproducibility. The nanochannel-based aptasensor and ternary ECL system demonstrates great potential in convenient and sensitive detection of cancer biomarker.

Spatial-resolved and self-calibrated 3D-printed photoelectrochemical biosensor engineered by multifunctional CeO2/CdS heterostructure for immunoassay

A spatial-resolved and self-calibrated photoelectrochemical (PEC) biosensor has been fabricated by a multifunctional CeO2/CdS heterostructure, achieving portable and sensitive detection of carcinoembryonic antigen (CEA) using a homemade 3D printing device. The CeO2/CdS heterostructure with matched band structure is prepared to construct the dual-photoelectrodes to improve the PEC response of CeO2. In particular, as the photoactive nanomaterial, the CeO2 also plays the role of peroxidase mimetic nanozymes. Therefore, the catalytic performance of CeO2 with different morphologies (e.g., nano-cubes, nano-rods and nano-octahedra) have been studied, and CeO2 nano-cubes (c-CeO2) achieve the optimal catalytic activity. Upon introducing CEA, the sandwich-type immunocomplex is formed in the microplate using GOx-AuNPs-labeled second antibody as detection antibody. As a result, H2O2 can be produced from the catalytic oxidization of glucose substrate by GOx, which is further catalyzed by CeO2 to form •OH, thus in situ etching CdS and decreasing the photocurrents. The self-calibration is achieved by the dual-channel photoelectrodes on the homemade 3D printing device to obtain the photocurrents ratio, thus effectively normalizing the fluctuations of external factors to enhance the accuracy. This integrated biosensor with a detection limit as low as 0.057 ng mL−1 provides a promising way for ultrasensitive immunoassay in clinic application in complex environments.

Cubic Na0.5Bi0.5TiO3nanoperovskite significantly expands the application of sensitive immunosensor for the detection of carcinoembryonic antigen.

Nanosized sodium bismuth perovskite titanate (NBT) was synthesized and first used as the electrochemical immune sensing platform for the sensitive detection of carcinoembryonic antigen (CEA). Gold nanoparticles (Au NPs) grew on the surface of NBT through forming Au-N bond to obtain Au@NBT, and a label-free electrochemical immunosensor was proposed using Au@NBT as an immunosensing recognizer towards CEA. The well-ordered crystal structure of NBT was not changed at all after the modification of Au NPs outside, but significantly improved the conductivity, catalytic activity, and biocompatibility of the Au@NBT-modified electrode. The unique cubic crystal nanostructure of NBT offered a large active area for both Au NP modification and the subsequent immobilization of biomolecules over the electrode surface, triggering the effective generation of promising properties of the proposed Au@NBT-based electrochemical immunosensor. As expected, favorable detection performances were achieved using this immunosensor towards CEA detection, where a good linear relationship between the current response and CEA concentration was obtained in the concentration range 10fg mL-1 to 100 ng mL-1 with a low detection limit (LOD) of 13.17fg mL-1. Also, the significantly enhanced selectivity, and stability guaranteed the promising electrochemical properties of this immunosensor. Furthermore, the analysis of real serum samples verified the high feasibility of this new method in clinical CEA detection. This work opens a new window for the application of nanoperovskite in the early detection of CEA.

Hydrangea-like TiO2/Bi2MoO6 porous nanoflowers triggering highly sensitive electrochemical immunosensing to tumor marker.

Rapid and sensitive detection of carcinoembryonic antigen (CEA) is of great significance for cancer patients. Here, molybdenum (Mo) was doped into bismuth oxide (Bi2O3) by one-pot hydrothermal method forming porous tremella Bi2MoO6 nanocomposites with a larger specific surface area than the spherical structure. Then, a new kind of hydrangea-like TiO2/Bi2MoO6 porous nanoflowers (NFs) was prepared by doping titanium into Bi2MoO6, where titanium dioxide (TiO2) grew in situ on the surface of Bi2MoO6 nanoparticles (NPs). The hydrangea-like structure provides larger specific surface area, higher electron transfer ability and biocompatibility as well as more active sites conducive to the attachment of anti-carcinoembryonic antigen (anti-CEA) to TiO2/Bi2MoO6 NFs. A novel label-free electrochemical immunosensor was then constructed for the quantitative detection of CEA using TiO2/Bi2MoO6 NFs as sensing platform, showing a good linear relationship with CEA in the concentration range 1.0pg/mL ~ 1.0mg/mL and a detection limit of 0.125pg/mL (S/N = 3). The results achieved with the designed immunosensor are comparable with many existing immunosensors used for the detection of CEA in real samples.

Functionalized gold nanoparticle enhanced nanorod hyperbolic metamaterial biosensor for highly sensitive detection of carcinoembryonic antigen

Hyperbolic metamaterial (HMM) biosensors based on metals have superior performance in comparison with conventional plasmonic biosensors in the detection of low concentrations of molecules. In this study, a nanorod HMM (NHMM) biosensor based on refractive index changes for carcinoembryonic antigen (CEA) detection is developed using secondary antibody modified gold nanoparticle (AuNP-Ab2) nanocomposites as signal amplification element for the first time. Numerical analysis based on finite element method is conducted to simulate the perturbation of the electric field of bulk plasmon polariton (BPP) supported by a NHMM in the presence of a AuNP. The simulation reveals an enhancement of the localized electric field, which arises from the resonant coupling of BPP to the localized surface plasmon resonance supported by AuNPs and is beneficial for the detection of changes of the refractive index. Furthermore, the AuNP-Ab2 nanocomposites-based NHMM (AuNP/Ab2-NHMM) biosensor enables CEA detection in the visible and near-infrared regions simultaneously. The highly sensitive detection of CEA with a wide linear range of 1–500 ng/mL is achieved in the near-infrared region. The detectable concentration of the AuNP/Ab2-NHMM biosensor has a 50-fold decrease in comparison with a NHMM biosensor. A low detection limit of 0.25 ng/mL (1.25 pM) is estimated when considering a noise level of 0.05 nm as the minimum detectable wavelength shift. The proposed method achieves high sensitivity and good reproducibility for CEA detection, which makes it a novel and viable approach for biomedical research and early clinical diagnostics.

Dual-potential ratiometric electrochemiluminescence based on single emitter and single coreactant for the sensitive detection of carcinoembryonic antigen

Dual-potential ratiometric electrochemiluminescence (ECL) is in favor of resistance to environmental interference. However, two kinds of emitters or coreactants, and a wide scan potential range (>2 V) are mandatory. This work developed a new dual-potential ratiometric ECL sensor for detection of carcinoembryonic antigen (CEA) using single emitter (luminol) and single coreactant (H2O2) with a mild potential range from −0.1 to 0.6 V. Luminol could produce a strong cathodic ECL (Ec) induced by hydroxyl radicals (HO‧) from the reduction of H2O2, and a relatively weak anodic ECL (Ea). After the ferrocene modified CEA aptamer (Apt-Fc) was attached, Fc could promote Ea by catalyzing the oxidation of H2O2, and reduce Ec by consuming HO‧. With the cycling amplification of the exonuclease I, CEA could substantially reduce the amount of Apt-Fc, resulting in the decrease of Ea and the rise of Ec. So, the ratio of Ec to Ea (Ec/Ea) was used as the detection signal, realizing the sensitive determination of CEA from 0.1 pg mL−1 to 10 ng mL−1 with a LOD of 41.85 fg mL−1 (S/N = 3). The developed sensor demonstrated excellent specificity, stability and reproducibility, with satisfactory results in practical detection.

Improving CEA detection Sensitivity: Carboxyfluorescein-Loaded liposomes in aptamer sandwich assay

This study aimed to develop an effective method for highly sensitive detection of carcinoembryonic antigen (CEA), a tumor biomarker, using an aptasensor sandwich assay based on a liposome loaded with carboxyfluorescein. In this approach, liposomes loaded with carboxyfluorescein (CF) were anchored with a cholesterol-labeled anti-CEA aptamer (Apt1-Lip) using a post-insertion technique. Furthermore, the successful insertion of the aptamer into the liposome outer layer was confirmed through UV absorption, PAGE electrophoresis, dynamic light scattering (DLS), and zeta potential measurements. Additionally, a secondary aptamer was conjugated with magnetic beads via biotin-streptavidin interactions and used as a capture probe (MBs/Apt2). Aptamer-decorated liposomes successfully bound to the CEA antigen in the presence of the target, leading to the formation of a sandwich assay when combined with MBs/Apt2. The specific binding signal was further increased by dissolving the lipid nanospheres with Triton X-100. This liposome-based aptasensor demonstrated a detection limit of 35.48 pg/mL over a wide linear range from 0.1 ng/mL to 100 ng/mL, with high specificity and sensitivity at CEA. Additionally, the proposed approach exhibited notable promise for on-site testing in early clinical diagnosis, as it showed excellent selectivity, satisfactory reproducibility, and good recovery in CEA detection from human serum samples.

A novel split-type photoelectrochemical biosensor based on liposome-induced in situ formation of Bi2S3@BiOI/Ag2S heterojunction for the sensitive detection of CEA

A novel split-type photoelectrochemical (PEC) biosensor was constructed for the sensitive detection of carcinoembryonic antigen (CEA) based on the Ag+-liposome (ALL) signal amplification strategy and Bi2S3@BiOI heterojunction as the substrate material. The split-type sensing mode effectively avoids the complex fixation of biomolecules on the electrode surface and preserves the activity of biomolecules. The sandwich complex was formed between CEA and aptamer-anchored streptavidin-functionalized magnetic beads (SMB-Apt) and ALL-labeled aptamer (ALL-Apt). After the methanol was added, a large amount of Ag+ was released from the liposome. The released Ag+ was transferred to the Bi2S3@BiOI modified electrode surface for incubation and then soaked in Na2S solution to form a narrow band gap photosensitive material Ag2S on the electrode surface. Bi2S3@BiOI/Ag2S ternary heterojunction in situ was formed due to the band gap matching relationship between Ag2S and the Bi2S3@BiOI heterojunction, which effectively expanded the light absorption range and enhanced the photocurrent signal. Under the optimal experimental conditions, the constructed PEC sensing platform exhibited good analytical performance for CEA with a linear range of 0.005 ∼ 50 ng mL−1 and a detection limit of 1.21 pg mL−1. Additionally, the PEC sensor had good selectivity, reproducibility, and stability, which provided a new research idea for the detection of clinical tumor biomarkers.

A dual-mode homogeneous electrochemical-colorimetric biosensing sensor for carcinoembryonic antigen detection based on a microfluidic paper-based analysis device.

Dual-mode-based sensors have drawn a lot of interest due to their high accuracy and sensitivity compared to single-response systems. A simple electrochemical and colorimetric dual-mode sensor based on enzyme-linked immunosorbent assay (ELISA), without complex electrode surface modification, was developed for accurate and sensitive detection of carcinoembryonic antigen (CEA). The target CEA is recognized by an antibody coupled to horseradish peroxidase (HRP), which then oxidizes the substrate 3,3',5,5'-tetramethylbenzidine (TMB) to generate both a colorimetric and an electrochemical signal. A paper-based analysis device (μPAD) with dual-mode homogeneous sensing microfluidic was created; three paper-based detection areas for colorimetric testing, and a two-electrode embedded detection area for electrochemical testing. When applying colorimetric analysis technology, the linear range of CEA detection is 0.6-40 ng mL-1, and the limit of detection (LOD) is 0.2 ng mL-1. The linear range is 0.1-40 ng mL-1 and the LOD is 0.03 ng mL-1 by applying electrochemical analysis. The visibility and intuitiveness of colorimetry provide a reference for higher sensitivity and quick response of the electrochemical method. A smartphone application (APP) was also developed to realize the dual extraction of colorimetric signals. The colorimetric detection system based on ELISA can provide a new path for the development of electrochemical sensing and makes it have inherent self-verification and self-correction functions and is expected to provide more reliable and accurate detection results.

2D Z-scheme ZnIn2S4/g-C3N4 heterojunction based on photoelectrochemical immunosensor with enhanced carrier separation for sensitive detection of CEA

Semiconducting materials based on photoelectrochemical (PEC) sensors have been widely utilized for detection. Meanwhile, the sensitivity of the PEC sensor was limited by low-efficiency carrier separation. Thus, a novel sandwich-type PEC bioimmunosensing based on 2D Z-scheme ZnIn2S4/g-C3N4 heterojunction as a photosensitive material and BiVO4 as a photoquencher was designed for the sensitive detection of carcinoembryonic antigen (CEA). Firstly, the 2D ZnIn2S4/g-C3N4 structure provided a multitude of activated sites which facilitated the loading of the capture antibody (Ab1). Secondly, the Z-scheme heterojunction had a high redox capacity while promoting the rapid separation and migration of photogenerated electron-hole pairs (e−/h+). Thus it was able to consume more electron donors to a certain extent, resulting in a higher initial photocurrent. In addition, BiVO4 with large spatial potential resistance was introduced for the first time to realize signal amplification. BiVO4 could not only compete with substrate materials for electron donors, but also effectively prevent electron donors from contacting the substrate, further reducing the photocurrent signal. Under optimized conditions, the sensor had a favorable detection range (0.0001–100 ng/mL) to CEA and a low detection limit of 0.03 pg/mL. With high specificity, excellent stability, and remarkable reproducibility, this sensor provided a new perspective for constructing accurate and convenient PEC immunosensor for bioanalysis and early disease diagnosisdisease diagnosis.

Development Pt/CoFe2O4/NC for efficient hydrogen evolution and sensitive detection of CEA

In this study, we designed a Pt/CoFe2O4/NC composite material as an excellent electrocatalyst for hydrogen evolution reaction (HER) and used the HER signal to construct an electrochemical immunosensor for carcinoembryonic antigen (CEA) detection. Remarkably, Pt/CoFe2O4/NC demonstrated superior HER performance compared to alternative Pt-based materials. It exhibited a low overpotential of only 42 mV and a Tafel slope of 253 mV dec−1 in acidic medium. Furthermore, due to the excellent conductivity, large surface area, and superior HER performance of Pt/CoFe2O4/NC, it was used as secondary antibody (Ab2) label to achieve signal amplification in the electrochemical immunosensor. The results showed that this immunosensor possessed high selectivity and sensitivity. The linear detection range is 1.0 × 10−4–5.0 ng mL−1, and the detection limit is 0.0134 pg mL−1. It has potential applications in the clinical analysis field.

Early Detection of Carcinoembryonic Antigen Using Hollow Nanospheres Improves the Outcome of Pediatric Solid Tumors

A sandwich electrochemical immunosensor was developed for sensitive detection of carcinoembryonic antigen (CEA) using hollow nanospheres composite material loaded with gold nanoparticles as the signal tag and gold triangular nanoplate as the substrate material. Samples obtained from pediatric solid tumor tissue and their blood samples were used to detect CEA using this nanoparticle. The hollow nanospheres constructed in this study, provided abundant reaction sites and high catalytic activity, while the loading of Au NPs enhances conductivity and biocompatibility. The immunosensor has good analytical ability in detecting CEA in the mass concentration range of 1 pg/mL to 50 ng/mL, with a low detection limit (LOD) of 0.37 pg/mL. This novel method provides a valuable tool for rapid clinical detection of CEA in the context of pediatric solid tumors.

Labeled free electrochemiluminescence aptamer platform based on one-step cathodic electrochemical growth of 2D/3D Ru-BTC-MOFs nanoparticles to detect carcinoembryonic antigen

[Ru(dcbpy)3]2+ functionalized 2D/3D hybrid metal–organic frameworks (Ru-BTC-MOFs), which performed good ECL performance, were synthesized by on one-step cathodic electrodeposition with Zn(NO3)2 as metal ion source, Ru(dcbpy)3Cl2) (tri(4,4-dicarboxybipyridine) ruthenium chloride) and H3BTC (1,3,5-phenyl tricarboxylic acid) as organic ligand. The effect of electrodeposition voltage, electrodeposition time, H3BTC and [Ru(dcbpy)3]Cl2 concentration on the morphology and ECL performance of Ru-BTC-MOFs were investigated in detail. An ECL biosensor platform for sensitive detection of carcinoembryonic antigen (CEA) was constructed by further modified AuNPs and aptamer on the Ru-BTC-MOFs/GCE. The specifically recognition and adsorption of CEA would hinder the electron transfer between Ru-BTC-MOFs and trinpropylamine (TPA) as the co-reactive agent, resulting in decreasing the ECL intensity. Under the optimal experimental conditions, the ECL intensity and logarithm of CEA concentration showed a good linear relationship in the concentration range of 10.0 fg/mL to 10.0 ng/mL, and the detection limit was 5.56 fg/mL. The proposed sensor performed acceptable reproducibility, repeatability, anti-interference ability and stability, and it would be expected to have broad application prospects in clinical trials.

Ultrathin mesoporous BiOCl nanosheets-mediated liposomes for photoelectrochemical immunoassay with in-situ signal amplification

Designing new biochemical sensors and achieving selectivity and high-sensitivity analysis is one of main research directions for immunoassays. Herein, a liposome-amplification photoelectrochemical (PEC) immunoassay was developed using ultrathin mesoporous bismuth chloride oxide nanosheets (BiOCl MSCN) for the highly selective and sensitive detection of carcinoembryonic antigen (CEA). Based on good photocurrent response of BiOCl MSCN toward dopamine, a liposome-conjugated secondary antibody loaded with dopamine was added for specific recognition in the presence of CEA. After the lysis treatment, the liberated dopamine was injected into the three-electrode electrolytic cell to enhance the photocurrent of BiOCl MSCN. Under the optimized conditions, the constructed liposome-mediated PEC immunoassay showed high sensitivity against CEA, with a dynamic response in the linear range of 0.05 ng mL−1 to 100 ng mL−1 and a detection limit of 35 pg mL−1. The present study proposes a new approach to the liposome-mediated PEC immunoassay constructed on ultrathin mesoporous BiOCl nanosheets, which can be used to target further the study of the sensing mechanism.

Difunctional Magnetic Nanoparticles Employed in Immunochromatographic Assay for Rapid and Quantitative Detection of Carcinoembryonic Antigen.

Immunochromatographic assay (ICA) plays an important role in in vitro diagnostics because of its simpleness, convenience, fastness, sensitivity, accuracy, and low cost. The employment of magnetic nanoparticles (MNPs), possessing both excellent optical properties and magnetic separation functions, can effectively promote the performances of ICA. In this study, an ICA based on MNPs (MNP-ICA) has been successfully developed for the sensitive detection of carcinoembryonic antigen (CEA). The magnetic probes were prepared by covalently conjugating carboxylated MNPs with the specific monoclonal antibody against CEA, which were not only employed to enrich and extract CEA from serum samples under an external magnetic field but also used as a signal output with its inherent optical property. Under the optimal parameters, the limit of detection (LOD) for qualitative detection with naked eyes was 1.0 ng/mL, and the quantitative detection could be realized with the help of a portable optical reader, indicating that the ratio of optical signal intensity correlated well with CEA concentration ranging from 1.0 ng/mL to 64.0 ng/mL (R2 = 0.9997). Additionally, method comparison demonstrated that the magnetic probes were beneficial for sensitivity improvement due to the matrix effect reduction after magnetic separation, and the MNP-ICA is eight times higher sensitive than ICA based on colloidal gold nanoparticles. The developed MNP-ICA will provide sensitive, convenient, and efficient technical support for biomarkers rapid screening in cancer diagnosis and prognosis.

An electrochemiluminescence immunosensor based on functionalized metal organic layers as emitters for sensitive detection of carcinoembryonic antigen

The concentration of carcinoembryonic antigen (CEA) is an important indicator for clinical monitoring and diagnosis of tumor. Early sensitive detection of CEA is significant for cancer diagnosis and therapy. In this study, a sensitive electrochemiluminescence (ECL) immunosensor was fabricated based on functionalized metal organic layers (MOLs) for the determination of CEA. In this immunosensor, Au nanoparticles (AuNPs) were grown on ultrathin two-dimensional MOLs via in situ reduction. AuNPs not only can accelerate the electron transfer but also can be used as the labels to conjugate with antibody. The as-prepared AuNPs@Ir-Zr-MOL nanocomposite showed high ECL efficiency and can be used as an ECL emitter owing to the great ECL property of Ir-Zr-MOL. The ECL intensity of AuNPs@Ir-Zr-MOL decreased linearly with the logarithm of CEA concentration in the range from 1.00 pg mL−1 to 100 ng mL−1. And the detection limit was 0.200 pg mL−1 (S/N = 3). What’s more, the as-prepared immunosensor worked well in human blood samples, showing its potential for real analysis.

Two-dimensional substrate assisted SERS immunosensor for accurate detection of carcinoembryonic antigen

Accurate and sensitive detection of carcinoembryonic antigen (CEA) is essential for the detection of various diseases in healthcare and the medical field. Currently, due to the high false negative rate of CEA assay in clinical setting and its use as a common indicator for early cancer screening, a novel CEA detection method with high sensitivity, increased specificity and the lower cost has become a clinical challenge. Here, a facile sandwich type immunosensor based on surface-enhanced Raman scattering (SERS) was presented including 4-mercaptobenzonitrile (4MBN) labeled gold core-silver shell nanoparticles (Au@4MBN@Ag NPs) as SERS tag and 4-mercaptophenylboronic acid (4-MPBA) functionalized two-dimensional (2D) silver nanoparticle film (Ag FM) as SERS capture substrate for CEA detection. A linearity of 10-9-10-14M was observed with high sensitivity and excellent selectivity for the detection of CEA. Additionally, the spiking experiment yielded 105.33–127.00% recovery with variation coefficients below 10% demonstrating high assay accuracy and precision. The immunosensor we proposed here is a promising approach to quantify CEA in liquid biopsy samples with high sensitivity, which could be further developed for early cancer screening.