Presence Of Alpha-fetoprotein Research Articles

Ratiometric electrochemical immunoassay based on 2D Co/Fe MOF decorated with toluidine blue and Fc-labeled Schiff base for accurate assay of alpha-fetoprotein in clinical serum

The high level of alpha-fetoprotein (AFP) expression is closely related to hepatocellular carcinoma (HCC). Herein, a dual signal ratiometric electrochemical immunosensor based on chitosan-ferrocenecarboxaldehyde-spindle gold (Chit-Fc-SAu) and Co/Fe metal-organic framework-toluidine blue/polydopamine (Co/Fe MOF-TB/PDA) was proposed for quantitative analysis of AFP. Specifically, Chit-Fc-SAu worked as a substrate to trap more primary antibodies (Ab1) generating the first electrochemical signal from Fc. Thanks to the large specific surface area, the synergistic and electronic effects of Co/Fe MOF nanosheets, and the rich functional groups of PDA, Co/Fe MOF-TB/PDA could load more secondary antibodies (Ab2) and signal molecules (TB) providing another amplified electrochemical signal. In the presence of AFP, Ab1-AFP-Ab2 formed a sandwich structure, and as the AFP concentration increased, the peak current ratio of TB to Fc (ITB/IFc) also increased. The dual signal ratiometric strategy can avoid environmental signal interference and achieve signal self-calibration, thereby improving the accuracy and reproducibility of detection. After a series of exploration, this self-calibrated ratiometric immunosensor exhibited a wide linear range (0.001−200 ng mL−1), a low detection limit (0.34 pg mL−1), and good repeatability. When applied to the assay of clinical serum samples, the detection results of ratiometric sensor were consistent with that of commercial electrochemiluminescence (ECL) immunoassay, significantly superior to that of non-ratiometric sensor. The self-calibrated strategy based on ratiometric sensor helps to improve the accuracy of AFP in clinical diagnosis.

A Real-World Experience on a Chinese Population of Patients With Unresectable Hepatocellular Carcinoma Treated With Nivolumab.

For unresectable hepatocellular carcinoma (HCC), nivolumab (anti-programmed death receptor-1 (PD-1)) is used as non-curative interventions. The aim of the study was to focus on the real-world experience of nivolumab applied to patients with HCC. Unresectable HCC patients receiving nivolumab treatments at Taichung Veterans General Hospital, from June 2018 to May 2020, were recruited. Exclusion criteria were Child-Pugh stage C, poor performance status, a lack of compliance or intolerable to drug treatments. The tumor radiological responses and survival outcomes of enrolled patients were collected and analyzed. Among a total of 57 patients, most of them were classified as Child-Pugh stage A (70.2%) and Barcelona Clinic Liver Cancer (BCLC) stage C (66.7%). Nivolumab was given to 14 (24.6%) as the primary-line, and 43 patients (75.4%) as the secondary-line systemic treatments. The mean therapeutic duration was 6.5 months. Objective response rate (ORR) was 24.6%, and disease control rate (DCR) was 42.1%. The overall median progression-free survival (PFS) was 5.8 months (95% confidence interval (CI): 1.1 - 10.6), and overall survival (OS) was 11.5 months (95% CI: 4.3 - 17.8). Immune-related adverse event (IRAE) was 8.8%. Presence of alpha-fetoprotein (AFP) response (a decline in AFP ≥ 10% from baseline) during therapy predicted the tumor radiological response (to objective response: hazard ratio (HR): 4.89, 95% CI: 1.14 - 21.00; to disease control: HR: 4.71, 95% CI: 1.32 - 16.81). Those with tumor radiological responses showed longer PFS and OS. Decline in AFP during therapy has a predicting role on HCC radiological responses to nivolumab. Achieving radiological responses had better survival outcomes.

Label-Free Homogeneous Electrochemical Aptasensor Based on Size Exclusion/Charge-Selective Permeability of Nanochannel Arrays and 2D Nanorecognitive Probe for Sensitive Detection of Alpha-Fetoprotein.

The labeling-free and immobilization-free homogeneous aptamer sensor offers advantages including simple operation, low cost, and high sensitivity, demonstrating great potential in rapid detection of tumor biomarkers in biological samples. In this work, a labeling-free and immobilization-free homogeneous aptamer sensor was conveniently fabricated by combining size exclusion and charge-selective penetration of a nanochannel-modified electrode and two-dimensional (2D) nanorecognition probe which can realize selective and highly sensitive detection of alpha-fetoprotein (AFP) in serum. Vertically ordered mesoporous silica film (VMSF) with ultra-small, uniform, and vertically aligned nanochannels was easily grown on the simple, low-cost, and disposable indium tin oxide (ITO) electrode. Through π-π interaction and electrostatic force, the AFP aptamer (Apt) and electrochemical probe, tris(bipyridine)ruthenium(II) (Ru(bpy)32+), were coloaded onto graphene oxide (GO) through simple incubation, forming a 2D nanoscale recognition probe (Ru(bpy)32+/Apt@GO). Owing to the size exclusion effect of VMSF towards the 2D nanoscale probe, the electrochemical signal of Ru(bpy)32+/Apt@GO could not be detected. In the presence of AFP, the specific binding of AFP to the aptamer causes the dissociation of the aptamer and Ru(bpy)32+ from GO, resulting in their presence in the solution. The efficient electrostatic enrichment towards Ru(bpy)32+ by negatively charged VMSF allows for high electrochemical signals of free Ru(bpy)32+ in the solution. Linear determination of AFP ranged from 1 pg/mL to 1000 ng/mL and could be obtained with a low limit of detection (LOD, 0.8 pg/mL). The high specificity of the adapter endowed the constructed sensor with high selectivity. The fabricated probe can be applied in direct determination of AFP in serum.

A selective off–on fluorescent aptasensor for alpha-fetoprotein determination based on N-carbon quantum dots and oxidized nanocellulose

A selective off–on aptasensor was designed to measure tumor marker alpha-fetoprotein (AFP). Nitrogen carbon quantum dots modified with aptamer was synthesized. The addition of oxidized nanocellulose to this system causes quenching of the fluorescence intensity. But in the presence of AFP, the aptamers bind strongly with AFP, resulting in the release of oxidized nanocellulose and an increase in the fluorescence intensity of Apt@N-CQDs. The important parameters on AFP determination were optimized through response surface methodology and central composite design. Under optimized conditions, the fluorescence intensity enhanced linearly with AFP concentration in the range of 0.03–7.0 µg L−1 with a detection limit of 0.008 µg L−1 and relative standard deviations of 2.2 and 3.8% (at 4.0 µg L−1 of AFP; for n = 6) for intra- and inter-day assays. The method was successfully applied for the determination of AFP in human serum samples.

Facile engineered polymeric microdevice via co-coupling of phenylboronic acid and Protein A for oriented antibody immobilization enables substantial signal enhancement for an enhanced fluorescence immunoassay

The powerful immunoassay has attracted increasing attention for detecting trace substances. Herein, based on the co-coupling of phenylboronic acid and Protein A for oriented antibodies immobilization, we proposed a polymeric device-based fluorescence immunoassay with enhanced assay performance for Alpha-fetoprotein (AFP) analysis. Unlike traditional physical absorption or chemical covalent conjugation to immobilize antibodies, in this immunoassay, the bioreactivity of AFP antibody was maximumly obtained owing to the oriented immobilization manner. The package density of AFP antibody on the polymethylmethacrylate (PMMA) surface is significantly improved because of the co-coupling case associated distance effect. In addition, the non-specific absorption is greatly inhibited with the combined using of zwitterionic 2-methacryloyloxyethyl phosphorylcholine (MPC) and bovine serum albumin (BSA). These integrated features facilitate the output of strong fluorescence in the presence of AFP but emit very weak background in the absence of AFP. After a typical sandwich immunoreaction, the recorded fluorescence intensity of the immunosensor is proportional to the AFP concentration, showing excellent sensitivity, specificity, and reliability for AFP determination. Comparative studies show the co-coupling is superior than its single coupling counterparts. We envision this unique immunoassay can provide a new avenue for building immunosensors in the fields of disease diagnosis, food safety detection, and environmental monitoring.

Fluorescence sensing strategy based on aptamer recognition and mismatched catalytic hairpin assembly for highly sensitive detection of alpha-fetoprotein

At present, alpha fetoprotein (AFP) is mainly used as a serum marker of primary Hepatocellular carcinoma. A simple, enzyme-free sensing strategy is introduced for highly sensitive fluorescence detection of AFP. This detection strategy is based on aptamer recognition and mismatched catalytic hairpin assembly (MCHA). At first, Trigger is locked by aptamer before the introduction of AFP in this aptamer-MCHA system. The aptamer preferentially combines with AFP via powerful attraction in the presence of AFP. This results in the release of trigger and initiation of MCHA cycle, thus forming the H1 and H2 double chain complexes (denoted as H1@H2). Finally, H1@H2 and double chain structure containing fluorophore and its quenched group- BHQ1 (denoted as F@Q) initiated displacement reaction, which caused double chain separation and fluorescence recovery. This assay produces a wide detection range, which is from 0.1 ng mL−1 to 10 μg mL−1 and the limit of detection as 0.033 ng mL−1. The whole detection process was performed at 37 °C for 60 min. In addition, this assay had high anti-interference ability and could be used to detect AFP in clinical serum. This novel AFP detection strategy is able to screen of Hepatocellular carcinoma.

An fluorescent aptasensor for sensitive detection of tumor marker based on the FRET of a sandwich structured QDs-AFP-AuNPs

The detection of alpha-fetoprotein (AFP) is of great importance for hepatocellular carcinoma (HCC) diagnosis, but it needs to be further improved because of poor sensitivity and complicated operating steps. In this paper, a simple and sensitive homogeneous apatasensor for AFP has been developed based on Förster resonance energy transfer (FRET) where the AFP aptamer labeled luminescent CdTe quantum dots (QDs) as a donor and anti-AFP antibody functional gold nanoparticles (AuNPs) as an acceptor. In the presence of AFP, the bio-affinity between aptamer, target, and antibody made the QDs and AuNPs close enough, thus the fluorescence of CdTe QDs quenched though the FRET between QD and AuNP. The fluorescent aptasensor for AFP showed a concentration-dependent decrease of fluorescence intensity in the low nanomolar range and a detecting linear range of 0.5–45 ng mL−1, with a detection limit of 400 pg mL−1. Moreover, this homogeneous aptasensor is simple and reliable, and obtained satisfying results for the detection of AFP in human serum samples. With more and more aptamers for biomarkers have been selected gradually, this approach could be easily extended to detection of a wide range of biomarkers. The proposed aptasensor has great potential for carcinoma screening in point-of-care testing and even in field use.

Metal coordination polymer induced perylene probe excimer fluorescence and its application in acetylcholinesterase sensing and alpha-fetoprotein immunoassay.

A novel sensing strategy for acetylcholinesterase (AChE) and alpha-fetoprotein (AFP) is developed, based on the perylene probe monomer to excimer fluorescence transformation induced by the in situ generation of a metal coordination polymer. In the presence of AChE, acetylthiocholine chloride was hydrolyzed to thiocholine. Ag+ and the produced thiocholine formed a positively charged metal coordination polymer, which induced the aggregation of a negatively charged perylene probe and the formation of probe excimer emission. The intensity ratio of excimer to monomer emission was proportional to the AChE concentration. A sensing method for AChE was thus established with a detection limit of 0.02 mU mL-1. The excimer emission with a large Stokes shift could avoid the interference of background fluorescence from complex biological samples, and thus achieved selective and sensitive detection of AChE. In addition, a fluorescence immunoassay strategy for AFP was then developed. Gold nanoparticles (AuNPs) co-immobilized with acetylcholinesterase and the AFP antibody as the capture and amplification probe were first prepared. In the presence of AFP, the sandwich structure was formed by immunological recognition. The hydrolysis of acetylthiocholine was catalyzed by AChE on the AuNPs, and the metal coordination polymer was then formed which resulted in the aggregation of the perylene probe and the formation of the excimer emission. The proposed sensing method offers a new strategy for the detection of other biomarkers.

An electrochemical immunosensor for AFP measurement based on the magnetic Fe3O4@Au@CS nanomaterials

An ultrasensitive electrochemical immunosensor was fabricated based on the magnetic Fe3O4@Au@CS nanomaterials for alpha fetoprotein (AFP). First, the Fe3O4@Au@CS nanocomposites were prepared with Fe3O4@Au NPs as the core and chitosan (CS) as the shell. Then, The human AFP antibody (Ab1) was immobilized on Fe3O4@Au@CS as the capture probe, the mouse anti-human AFP antibody (Ab2) and horseradish peroxidase (HRP) were conjugated on the gold nanoparticles (Au NPs) as the detection probe. In the presence of AFP, the immunosensor Fe3O4@Au@CS-Ab1@AFP@Ab2-Au-HRP was formed via specific recognition of antigen and antibody. Due to the immobilized HRP catalyzed the decomposition of H2O2 resulting in a substantial current, the response signal of the sensor was recorded by the amperometric (i-t) method. The current response presented the linear relationship to the concentration of AFP, a dynamic range from 0.01 to 8 μg/mL, with the detection limit of 1.78 ng/mL.

Alpha-Fetoprotein in Retina and Lens of the Human Eye at Early Stages of Prenatal Development

The presence of alpha-fetoprotein (AFP) was shown in the retina and lens of the human fetal eye at different stages of prenatal development. PCR analysis revealed AFP mRNA neither in the retina nor in the lens, whereas in the fetal liver (control) AFP mRNA was found to be expressed. The data obtained indicate that AFP is not synthesized in retinal and lens cells of the human fetal eye but is imported from elsewhere to be taken up by these cells. The presence of AFP in the retina and lens implies its involvement in early morphogenesis and differentiation of these ocular tissues during prenatal human development.

WS2 nanosheets-sensitized CdS quantum dots heterostructure for photoelectrochemical immunoassay of alpha-fetoprotein coupled with enzyme-mediated biocatalytic precipitation.

Based on enzymatic biocatalytic precipitation to quench the amplified photocurrent response generated from WS2 nanosheets-sensitized CdS quantum dots heterostructure, a novel photoelectrochemical immunosensor was constructed for sensitive alpha-fetoprotein (AFP) monitoring. The immunosensor comprised an anti-AFP antibody and a horseradish peroxidase-tagged anti-AFP antibody (HRP-Ab2), which served as a capture unit and a signal indicator, respectively. In the presence of AFP, HRP-Ab2 was immobilized on the electrode surface for establishing a sandwich-type immunocomplex via antigen-antibody interaction, and subsequently catalyzed 4-chloro-1-naphthol to form the nonconductive and insoluble precipitate. This precipitation effectively impeded the diffusion and electron transfer of the electron donor, thus achieving decreased photocurrent. Under optimized conditions, excellent linearity range (1 pg mL-1-20 ng mL-1), satisfactory detection limit (0.43 pg mL-1), desirable selectivity and good stability were obtained for the as-designed immunosensor. Moreover, the application of AFP determination in human serum allowed the immunosensor to hold great potential for early diagnostics of some cancer diseases.

A Fe3O4@Au-basedpseudo-homogeneous electrochemical immunosensor for AFP measurement using AFP antibody-GNPs-HRP as detection probe

In this study, a Fe3O4@Au-based pseudo-homogeneous electrochemical immunosensor was prepared for detection of alpha fetoprotein (AFP), a well-known hepatocellular carcinoma biomarker. The primary antibody (Ab1) was immobilized on Fe3O4@Au NPs as the capture probe. Horseradish peroxidase (HRP) and secondary antibody (Ab2) were conjugated on gold nanoparticles (GNPs) through electrostatic adsorption to form signal-amplifying labels. In the presence of AFP, a sandwich immunocomplex was formed via specific recognition of antigen-antibody in a Fe3O4@Au-basedpseudo-homogeneousreaction system. After the immunocomplex was captured to the surface of magnetic glassy carbon electrode (MGCE), the labeling HRP catalyzed the decomposition of H2O2, resulting in a substantial current for the quantitative detection of AFP. The amperometric (i-t) method was employed to record the response signal of the immunosensor based on the catalysis of the immobilized HRP toward the reduction of H2O2 with hydroquinone (HQ) as the redox mediator. Under the optimal conditions, the amperometric current response presented a linear relationship with AFP concentration over the range of 20 ng/mL-100 ng/mLwith a correlation coefficient of 0.9940, and the detection limit was 0.64 ng/mL at signal/noise [S/N] = 3. Moreover, the electrochemical immunosensor exhibited higher anti-interference ability, acceptable reproducibility and long-term stability for AFP detection.

Sensitive fluorescence immunoassay of alpha-fetoprotein through copper ions modulated growth of quantum dots in-situ

A novel fluorescence immunoassay has been developed for alpha-fetoprotein (AFP) detection based on copper ions (Cu2+) regulated formation of quantum dots in situ. In place of traditionally used fluorophore or enzyme for signal amplification, CuO nanoparticles (NPs) were used as signal amplifier to enhance the detection sensitivity. In the presence of AFP, CuO NPs-labeled antibody can be specifically captured through the sandwich-type immunoreaction. By the use of l-cysteine (Cys) as stabilizer, aqueous fluorescent CdS quantum dots (QDs) can be formed by a facile synthesis method. After acid dissolution, numerous Cu2+ ions were released from the CuO NPs, which can act as catalyst to catalyze the oxidization of Cys and thus greatly reduce the amount of CdS QDs formed. The fluorescence intensity showed a good linear relationship with the AFP concentration in the range from 1 to 80ng/mL, as low as 0.45ng/mL AFP can be detected. The high throughput, disposability, sensitivity and accuracy of the proposed fluorescence immunoassay showed good applicability in clinical diagnosis.

SERS- and luminescence-active Au-Au-UCNP trimers for attomolar detection of two cancer biomarkers.

Alpha-fetoprotein (AFP) and mucoprotein1 (mucin-1) are two important disease biomarkers. Self-assembled gold nanoparticles (AuNPs) and upconversion nanoparticle (Au-Au-UCNP) trimers based on aptamers were developed for the ultrasensitive detection of AFP and mucin-1. The Au-Au-UCNP trimers produced ideal optical signals, with prominent Raman enhancement and fluorescence quenching effects. The surface-enhanced Raman scattering (SERS) intensity decreased in the presence of mucin-1 and the luminescence intensity increased in the presence of AFP. A limit of detection (LOD) of 4.1 aM and a wide linear range of 0.01-10 fM for the detection of mucin-1 were obtained with this SERS-encoded sensing system. Using the luminescence-encoded sensing system, a LOD of 0.059 aM and a wide linear range of 1-100 aM for the detection of AFP were obtained. These LODs are the lowest values reported so far. This approach has the advantage of detecting two disease biomarkers simultaneously.

An integrated giant magnetoimpedance biosensor for detection of biomarker

A Dynabeads-labeled magnetic immunoassay (MIA) has been developed by using an integrated giant magnetoimpedance (GMI) biosensor for the detection of alpha-fetoprotein (AFP). The GMI biosensor (Cr/Cu/NiFe/Cu/NiFe/Al2O3/Cr/Au films) integrated magnetic sensing elements and a biomolecular immunoplatform. Au film was modified with 11-Mercaptoundecanoic acid (11-MUA) for the immobilization of AFP monoclonal antibody. Double antibody sandwich immunoassay was used to specifically capture and label AFP antigen. Functionalized Dynabeads were conjugated to AFP antigen by streptavidin–biotin binding assay. GMI responses were measured for sensitive detection of AFP from 1 to 10ng/ml. Our results revealed that the presence of AFP on the biosensor improved the GMI effect owing to the induced magnetic dipole of superparamagnetic Dynabeads, and the GMI ratio was greatly increased at high frequency. Specificity of MIA was tested through the use of 1% bovine serum albumin (BSA). The underlying biophysical mechanisms responsible for the enhanced GMI effect in the detection of AFP were discussed. This work provides a complex lab-on-chip MIA for the detection of biomarker, which may open up a new way for the development of GMI-based MIA in clinical trials.

Metastatic hepatocellular carcinoma presenting as gynecomastia in male: A diagnostic dilema in fine needle aspiration cytology

Metastatic hepatocellular carcinoma presenting as gynecomastia in male: A diagnostic dilema in fine needle aspiration cytology

The effect of alpha fetoprotein on NF-κB translocation in lipopolysaccharide induced monocyte-derived dendritic cell

Background: Alpha fetoprotein (AFP) is a tumor-associated Ag that has a function in both ontogenic and oncogenic growth and its serum level is elevated in patients with hepatocellular carcinoma (HCC). A recent study showed that the immunoregulatory effect of AFP was through impairment of dendritic cell function as antigen presenting cell (APC), a mechanism that is known to hamper efficient antitumor response. However, the underlying intracellular mechanism of action of AFP required elucidation. As an initial step to determine the signaling pathway of AFP, we analyzed whether LPS induced NF-κB translocation occured in AFP-treated monocyte-derived dendritic cell (MDDC), which was induced by lipopolysaccharide (LPS). Methods: Monocytes were cultured in GM-CSF (800 ng/mL) and IL-4 (1000 ng/mL) containing medium and incubated for six days to generate immature MDDCs with or without the presence of AFP. Mature MDDC was generated by stimulation of the immature MDDC with LPS for another 30 minutes. The analysis of NF-κB translocation was measured by fluorescent microscopy. Results: Following activation of MDDC by LPS, the control group showed a marked nuclear staining of NF-κB. However, the AFP-treated group showed negative nuclear staining similar as observed in unactivated MDDC. Conclusion: This study demonstrated that AFP prevented the activation and nuclear translocation of NF-κB and subsequently might cause the impairment of MDDC function as APC. This finding provides a new insight on the role of AFP in the suppression mechanism of anti tumor immune response. (Med J Indones. 2012;21:97-101)

Non‐invasive diagnostic criteria for hepatocellular carcinoma: The value of contrast washout at imaging and the death of alpha‐fetoprotein

Non‐invasive diagnostic criteria for hepatocellular carcinoma: The value of contrast washout at imaging and the death of alpha‐fetoprotein

Primary Yolk Sac Tumor of the Lung

Yolk-sac tumor mimics the yolk sac of the embryo, and the presence of alpha fetoprotein in the tumor cells is highly characteristic. We present an 18-year-old boy with primary pulmonary yolk-sac tumor diagnosed postoperatively. A computed tomographic scan revealed a huge intrathoracic soft tissue mass 20 x 25 cm occupying most of the left hemithorax. Two trials of computed tomographic-guided needle biopsy were nonconclusive. A left upper lobectomy was performed with a complete tumor resection. Postoperatively, the patient's alpha fetoprotein (AFP) was 10,512 IU/mL with gradual decline under chemotherapy. The patient is alive 10 months after surgery and is disease free.

The intracellular mechanism of alpha-fetoprotein promoting the proliferation of NIH 3T3 cells.

The existence and properties of alpha-fetoprotein (AFP) receptor on the surface of NIH 3T3 cells and the effects of AFP on cellular signal transduction pathway were investigated. The effect of AFP on the proliferation of NIH 3T3 cells was measured by incorporation of 3H-TdR. Receptor-binding assay of 125I-AFP was performed to detect the properties of AFP receptor in NIH 3T3 cells. The influences of AFP on the [cAMP]i and the activities of protein kinase A (PKA) were determined. Western blot was used to detect the change of K-ras P21 protein expression. The proliferation of NIH 3T3 cells treated with 0-80 mg/L of AFP was significantly enhanced. The Scatchard analysis indicated that there were two classes of binding sites with KD of 2.722 x 10(-9)M (Bmax=12810 sites per cell) and 8.931 x 10(-8)M (Bmax=119700 sites per cell) respectively. In the presence of AFP (20 mg/L), the content of cAMP and activities of PKA were significantly elevated . The level of K-ras P21 protein was upregulated by AFP at the concentration of 20 mg/L. The monoclonal antibody against AFP could reverse the effects of AFP on the cAMP content, PKA activity and the expression of K-ras p21 gene. The effect of AFP on the cell proliferation was achieved by binding its receptor to trigger the signal transduction pathway of cAMP-PKA and alter the expression of K- ras p21 gene.