Detection Of Alpha-fetoprotein Research Articles

Visualizing alpha-fetoprotein level in undiluted serum based on microfluidic particle accumulation

Alpha-fetoprotein (AFP) is an abundant plasma protein produced by the liver of the human fetus. When abnormally elevated in adult serum, its level can be an essential biomarker for various cancers. In addition, maternal AFP serum levels can be used to screen congenital disorders such as down syndrome and neural tube defects. Here, we report a portable method for visualizing AFP levels in serum. Magnetic microparticles (MMPs) and polystyrene microparticles (PMPs) are designed to bind with AFP simultaneously. By loading the particle solution into a microfluidic chip with a magnetic separator, unconnected PMPs can be separated and continue flowing forward until being trapped at a particle dam. Ultimately, the accumulation length of PMPs enables visualization of AFP levels. This device can be adapted to sensitive mode (70 min incubation) with a limit of detection (LOD) of 15.8 ng/ml and rapid mode (15 min incubation) with a LOD of 34.3 ng/ml in undiluted serum samples, providing a strategy for fast and visual quantitative detection of serum AFP.

Application of a Novel One-Side Cell Quartz Crystal Microbalance Immunosensor in the Determination of Alpha-Fetoprotein from Human Serum.

The rapid and accurate detection of alpha-fetoprotein (AFP) levels is of great significance for the diagnosis and later treatment evaluation of liver cancer. In this study, a novel integrated quartz crystal microbalance (QCM) immunosensor based on the design to contact liquids on one side only was developed for the label-free detection of AFP. Anti-AFP mouse monoclonal antibodies were immobilized onto the upper electrode surface of the pre-treatment crystals using the staphylococcus aureus protein A. The AFP antigens in human serum were captured by specific surface-coated antibodies, and testing was carried out by monitoring the corresponding changes in frequency. The concentration range of the antigen detected was 13-760 ng/mL. The frequency characteristics of the process of antibody immobilization were investigated in detail, and high reproducibility of AFP antibody immobilization was achieved (standard deviation (SD) = 2.2 Hz). The developed QCM measurement system demonstrated a short test time (only 30 min), good reproducibility (the biological activity can still maintain more than 90% of the first test till it is reused five times), and accuracy as good as the one achieved with the radioimmunoassay (the maximum relative deviation = 4.8%). The designed QCM test system can easily and quickly detect AFP concentrations up to 760 ng/mL, indicating that the developed QCM assay is likely to lead to an alternative approach in large-scale screening for liver cancer in the near future.

Two–dimensional metal–organic framework nanosheets: An efficient two–electron oxygen reduction reaction electrocatalyst for boosting cathodic luminol electrochemiluminescence

Exploration of electrocatalytic–luminol systems is still in the developmental stages because of the weak electrochemiluminescence (ECL) of cathodic luminol, and it is still a challenge to establish a conformational relationship between electrocatalytic materials and ECL performance. Herein, functionalized two–dimensional NiZn metal–organic framework (MOF) nanosheets were synthesized using controlled heat treatment and were successfully applied to the two-electron (2e−) oxygen reduction reaction (ORR) to produce H2O2. Interestingly, it was found that both the intermediates and products of the ORR significantly affected the ECL emission of luminol. It is worth noting that extending NiM MOF (M = Fe, Co, and Zn) to 2e− ORR reaction and achieving efficient luminol emission is undoubtedly beneficial for constructing cathodic luminol systems. This work demonstrates the relationship between the electrocatalytic materials and luminol ECL performance, thereby, broadening the applications of ECL reactions. Finally, the proposed biosensor was successfully used for the sensitive detection of alpha-fetoprotein (AFP).

Portable smartphone‐based microfluidic electrochemical immunosensor for ultrasensitive detection of alpha‐fetoprotein in human serum

AbstractRapid and accurate tracing of biomarkers is essential for early detecting and diagnosing of cancer. Therefore, a valid and convenient strategy needs to be developed for efficient monitoring of cancer biomarkers. Herein, we constructed a portable microfluidic electrochemical immunosensor based on three‐dimensional reduced graphene oxide (3D rGO) doped with gold nanoparticles (Au NPs) for ultrasensitive determination of alpha‐fetoprotein (AFP). The designed microfluidic chip, with the advantages of small injection volume, detachable structure and high integration, was fabricated by 3D printing, which only needed 9 μL of reagent to realize the high sensitivity detection. In addition, the 3D Au NPs‐rGO composites with high specific surface area and electrons transfer capacity can effectively increase electroactive sites and enhance electrochemical signals. Benefiting from these features, the 3D Au NPs‐rGO microfluidic electrochemical immunochip showed a wide detection range between 0.1 pg/mL–200 ng/mL and a best detection limit of 0.045 pg/mL with the high sensitivity of 175.008 μA (ng/mL)−1 cm−2. Meanwhile, the proposed immunosensor exhibited reliable AFP detection in human serum samples, which demonstrated that this portable smartphone‐based microfluidic electrochemical immunosensor hold great promises in clinical detection and huge potential in personalized healthcare.

A simple, sensitive, label-free electrochemical immunosensor based on the chitosan-coated silver/cerium oxide (CS@Ag/CeO2) nanocomposites for the detection of alpha-fetoprotein (AFP)

Metal oxide-based sensors have the benefit of inexpensive, quick response, and high sensitivity in detecting specific biological species. In this article, a simple electrochemical immunosensor was fabricated using antibody-chitosan coated silver/cerium oxide (Ab-CS@Ag/CeO2) nanocomposites on a gold electrode for sensitive alpha-fetoprotein (AFP) diagnosis in human serum samples. Successfully synthesis of AFP antibody-CS@Ag/CeO2 conjugates was confirmed through Fourier transform infrared spectra of the prototype. The amine coupling bond chemistry was then used to immobilize the resultant conjugate on a gold electrode surface. It was observed that the interaction of the synthesized Ab-CS@Ag/CeO2 nanocomposites with AFP prevented an electron transfer and reduced the voltammetric Fe(CN)6 3−/4− peak current, which was proportional to the amount of AFP. The linear ranges of AFP concentration were found from 10−12–10−6 g.ml−1. The limit of detection was calculated using the calibration curve and came out to be 0.57 pg.ml−1. The designed label-free immunosensor successfully detected AFP in human serum samples. As a result, the resulting immunosensor is a promising sensor plate form for AFP detection and could be used in clinical bioanalysis.

Construction of a competitive electrochemical immunosensor based on sacrifice of Prussian blue and its ultrasensitive detection of alpha-fetoprotein

Effective signal amplification is a prerequisite for ultrasensitive detection by electrochemical immunosensors. For quantitative and ultrasensitive detection of alpha-fetoprotein (AFP), we designed a competitive electrochemical immunosensor and transferred the immunoreactivity from the electrode surface to the cuvette. AFP antigen was captured using AFP primary antibody (Ab1) immobilized on magnetic nanobeads (MBs), and ZIF-8 nanomaterials attached to secondary antibody (Ab2) were used as probes. MBs helped retain the sandwich structure in the test tube through incubation and washing steps. Then, an appropriately fixed excess of sodium ethylenediaminetetraacetic acid (EDTA) solution was added to the cuvettes, resulting in etching of Zn ions from ZIF-8 and formation of Zn-EDTA complexes. After magnetic separation, a certain amount of supernatant is added dropwise to the Prussian blue (PB)-modified electrode (GCE), and Fe ions (from PB) complex with the remaining EDTA in the supernatant, thus reducing the signal response value of PB. The higher the AFP concentration, the lower the amount of free EDTA in the supernatant, the less the destruction of PB, and therefore the higher the current. Under optimal conditions, the immunosensor achieved ultra-sensitive detection of AFP in the range of 10−4 ng/mL-100 ng/mL with a limit of detection (LOD) as low as 0.032 pg/mL (S/N = 3). The excellent performance provides an important tool for the early screening and detection of AFP.

Electrochemical immunosensor based on Fe3O4/MWCNTs-COOH/AuNPs nanocomposites for trace liver cancer marker alpha-fetoprotein detection

An electrochemical biosensor based on iron tetroxide (Fe3O4)/carboxylated carbon nanotubes (MWCNTs-COOH)/gold nanoparticles (AuNPs) was designed for the detection of alpha-fetoprotein (AFP), which is often used as an important indicator for the early clinical diagnosis of liver cancer markers. The Fe3O4/MWCNTs-COOH nanocomposite was synthesized by a solvothermal method and it combined with gold nanoparticles (AuNPs) deposited at the constant potential on a glassy carbon electrode to form Fe3O4/MWCNTs-COOH/AuNPs, which intensifies the electrical signal while the large active sites enable more stable immobilization of the AFP monoclonal antibodies on the electrode. The electrochemical performance of Fe3O4/MWCNTs-COOH/AuNPs was investigated in detail and the electrochemical response signal after the immune reaction with the AFP antigen-antibody was recorded. The peak current Ip of the response signal is linearly proportional to the lgcAFP in the range of 1 pg mL−1–10 μg mL−1, with a detection limit of 1.09034 pg mL−1 and good performance in clinical sample testing. The proposed sensor has shown great application and development potential in clinical medicine field.

An integrated and flexible PDMS/Au film-based electrochemical immunosensor via Fe–Co MOF as a signal amplifier for alpha fetoprotein detection

Ultrasensitive determination of tumor marker (TM) is of great significance in cancer prevention and diagnosis. Traditional TM detection methods involve large instrumentation and professional manipulation, which complicate the assay procedures and increase the cost of investment. To resolve these problems, an integrated electrochemical immunosensor based on the flexible polydimethylsiloxane/gold (PDMS/Au) film with Fe–Co metal-organic framework (Fe–Co MOF) as a signal amplifier was fabricated for ultrasensitive determination of alpha fetoprotein (AFP). First, gold layer was deposited on the hydrophilic PDMS film to form the flexible three-electrode system, and then the thiolated aptamer for AFP was immobilized. Afterward, the aminated Fe–Co MOF possessing high peroxidase-like activity and large specific surface area was prepared by a facile solvothermal method, and subsequently the biofunctionalized MOF could effectively capture biotin antibody (Ab) to form MOF-Ab as a signal probe and amplify the electrochemical signal remarkably, thereby realizing highly sensitive detection of AFP with a wide linear range of 0.01–300 ng/mL and a low detection limit of 0.71 pg/mL. In addition, the PDMS based-immunosensor showed good accuracy for assaying of AFP in clinical serum samples. The integrated and flexible electrochemical immunosensor based on the Fe–Co MOF as a signal amplifier demonstrates great potential for application in the personalized point-of-care (POC) clinical diagnosis.

Paper-based sensors for visual detection of alkaline phosphatase and alpha-fetoprotein via the distance readout

The development of paper-based sensors with the distance readout is particularly attractive for the point-of-care testing (POCT) of biomarkers. Herein, we report a paper-based sensor that can convert the viscosity change caused by the hydrogel degradation into the variance of water flow distance on the paper. The detection of alkaline phosphatase (ALP) and alpha-fetoprotein (AFP) is demonstrated as examples. Copper alginate (Cu-Alg) hydrogel can be formed when mixing the aqueous solutions of Cu2+ and alginate. The introduction of pyrophosphate ion (PPi) induces the gel-sol transition due to the high affinity between Cu2+ and PPi. However, in the presence of ALP, the gel-sol transition is prevented due to the hydrolysis of PPi by ALP. In these processes, the viscosity changes of the hydrogels are translated into the differences of the flow distances on the pH test papers. In addition, the tilt of the papers can increase the accuracy of detection. The detection of AFP is also fulfilled via the construction of the paper-based immunosensor using the ALP-linked AFP detection antibody. The developed paper-based sensors show excellent performance for the quantitative detection of biomarkers in real samples with remarkable selectivity. Overall, this convenient method has great potential in POCT applications.

A graphene-assisted electrochemical sensor for detection of alpha-fetoprotein in serum

Alpha fetoprotein (AFP) is a specific tumor marker for the diagnosis of primary liver cancer. In this work, a molecularly imprinted (MIP) electrochemical sensor for AFP was prepared by surface imprinting method. The MIP electrochemical biosensor uses polysulfide cordial and graphene-gold composite as electrode modified nanomaterials to effectively enhance the detection of electrical signals. Dopamine (DA) is the functional monomer and the PDA-AFP complex is obtained by electropolymerization. The eluent elutes the functional monomer and the specific cavity formed can adsorb the target molecule. Under optimal experimental conditions, differential pulse voltammetry (DPV) was used for detection. The current of the prepared biosensor decreases with increasing AFP concentration. The peak current value of DPV assay showed good linearity with the logarithm of AFP concentration in the range of 0.01 ng/mL-1000 ng/mL. The detection limit can reach 3.7 pg/mL.

Detection of Alpha Fetoprotein Based on AIEgen Nanosphere Labeled Aptamer Combined with Sandwich Structure of Magnetic Gold Nanocomposites.

As a biomarker, alpha-fetoprotein (AFP) is valuable for detecting some tumors in men, non-pregnant women, and children. However, the detection sensitivity in some methods needs to be improved. Therefore, developing a simple, reliable, and sensitive detection method for AFP is important for non-malignant diseases. An aptamer binding was developed based on aggregation-induced emission luminogen (AIEgen) nanosphere labeled with Fe3O4@MPTMS@AuNPs. AFP was detected with a sandwich structure of AuNPs magnetic composite particles. An aggregation-induced emission (AIE) molecule and polystyrene (PS) nanosphere complex were assembled, enhancing the fluorescence and improving the sensitivity of detection. The limit of detection (LOD) was at a given level of 1.429 pg/mL, which can best be achieved in serum samples. Finally, the results obtained showed the complex to be promising in practical applications.

Enhanced Photoelectrochemical Detection of Alpha-Fetoprotein Using Dipole Image Effect and Lock-In Amplification

Alpha-fetoprotein (AFP) is a serum biomarker mainly for early stage diagnosis and prognosis of primary liver cancer in clinical analysis. As a label-free analyte-specific biosensor with ultrahigh sensitivity and broad detection range, photoelectrochemical (PEC) sensor is promising for AFP detection. A unique feature of the PEC sensor, the separation of its excitation source and the detection signal, offers a great opportunity in the spatial and temporal domains to enhance its performance. For the spatial domain, AuNPs/TiO2/Au (in short, ATA) sandwiched structure was designed for magnetic resonance generation and light absorption enhancement. The strong light–matter interaction due to the dipole image effect has achieved an over 20 times increase in the sensitivity of the designed sensor. Instead of the typical method that manually switches the light source for photocurrent, lock-in amplification (LIA) was proposed to modulate the light source in the temporal domain. Such modulated signal can be coherently amplified and extracted from a strong noise background, which improves the signal-to-noise ratio (SNR) of the photocurrent signal and leads to a larger measurement range. This designed AFP biosensor exhibited one-order-of-magnitude wider linear detection range from 10 pg mL <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{1}}$ </tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1~\mu \text{g}$ </tex-math></inline-formula> mL <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{1}}$ </tex-math></inline-formula> with a detection limit of 4.5 pg mL <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{1}}$ </tex-math></inline-formula> .

AIEgens-Doped Photonic Crystals for High Sensitivity Fluorescence Detection of Tumor Markers

Detection of tumor markers is of great significance to preliminarily judge whether patients have malignant tumors. Fluorescence detection (FD) is an effective means to achieve sensitive detection of tumor markers. Currently, the increased sensitivity of FD has attracted research interest worldwide. Here, we have proposed a method of doping luminogens with aggregation-induced emission (AIEgens) into photonic crystals (PCs), which can significantly enhance the fluorescence intensity to achieve high sensitivity in the detection of tumor markers. PCs are made by scraping and self-assembling, which has the special effect of fluorescence enhancement. The combination of AIEgens and PCs can enhance the fluorescence intensity 4-7 times. These characteristics make it extremely sensitive. The limit of detection (LOD) for the detection of alpha-fetoprotein (AFP) in the AIE10 (Tetraphenyl ethylene-Br) doped PCs with a reflection peak of 520 nm is 0.0377 ng/mL. LOD for the detection of carcinoembryonic antigen (CEA) in the AIE25 (Tetraphenyl ethylene-NH2) doped PCs with a reflection peak of 590 nm is 0.0337 ng/mL. Our concept offers a good solution for highly sensitive detection of tumor markers.

Redox-labelled detection probe enabled immunoassay for simultaneous detection of multiple cancer biomarkers.

Some of the cancer biomarkers often lack specificity and sensitivity; thus, simultaneous detection of multiple biomarkers can make the diagnosis more accurate. Also, simple sensing system without utilization of extra reagents like mediator or substrate during detection event is desirable for point-of-care testing. To address this, mediator and substrate-free amperometric biosensor for simultaneous detection of cancer biomarkers carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) have been demonstrated by designing two different redox-labelled detection probes. Colloidal nanoparticles of polyaniline-pectin conjugated with AFP antibody along with ferrocene and silver nanoparticles conjugated with CEA antibody along with anthraquinone were used as redox probes to bind with AFP and CEA during the detection event. Sensor constructed using carboxylic acid tethered polyaniline as immobilization matrix displayed 5 times wider linear range than conventional polyaniline for AFP and CEA detection by sandwich electrochemical assay. The detection limit was 30pgmL-1 for AFP and 80pgmL-1 for CEA. The biosensor displayed appropriate sensitivity, good specificity, and negligible cross-reactivity between the two targets. The proposed sensor was used to determine APF and CEA in human blood serum. The strategy demonstrated can be further extended for detection of panel of cancer biomarkers by designing appropriate redox probes.

Homogeneous Electrochemical Immunoassay Using an Aggregation–Collision Strategy for Alpha-Fetoprotein Detection

Homogeneous immunoassays represent an attractive alternative to traditional heterogeneous assays due to their simplicity and high efficiency. Homogeneous electrochemical assays, however, are not commonly accessed due to the requirement of electrode immobilization of the recognition elements. Herein, we demonstrate a new homogeneous electrochemical immunoassay based on the aggregation-collision strategy for the quantification of tumor protein biomarker alpha-fetoprotein (AFP). The detection principle relies on the aggregation of AgNPs induced by the molecular biorecognition between AFP and AgNPs-anti-AFP probes, which leads to an increased AgNP size and decreased AgNP concentration, allowing an accurate self-validated dual-mode immunoassay by performing nanoimpact electrochemistry (NIE) of the oxidation of AgNPs. The intrinsic one-by-one analytical capability of NIE as well as the participation of all of the atoms of the AgNPs in signal transduction greatly elevates the detection sensitivity. Accordingly, the current sensor enables a limit of detection (LOD) of 5 pg/mL for AFP analysis with high specificity and efficiency. More importantly, reliable detection of AFP in diluted human sera of hepatocellular carcinoma (HCC) patients is successfully achieved, indicating that the NIE-based homogeneous immunoassay shows great potential in HCC liquid biopsy.

Electrochemical Sensor Based on Nanomaterials and Its Application in the Detection of Alpha Fetoprotein.

Hepatocellular carcinoma development and many other tumors are closely related to alpha-fetoprotein (AFP), its determination can be used as a positive test for tumors. It is mainly used clinically as a serum marker to diagnose and monitor the efficacy of primary hepatocellular carcinoma. Therefore, a variety of biosensors have been developed to detect AFP. Electrochemical sensors integrate a variety of detection methods. They have inherent advantages over other types of sensors, they are fast, portable, simple, and highly sensitive. Some meaningful electrochemical biosensors work with nanomaterials acting as signal amplification elements or as signal amplification catalysts. This review introduced the field of biosensors and discuss about the use of nanomaterials in electrochemical sensing, specificity electrochemical biosensing of AFP. The study ends with a discussion about the prospects for nanomaterial-based signal amplification and future research directions.

Preparation of Janus fluorescent probe based on an asymmetrical silica and its application in glucose and alpha-fetoprotein detection.

Janus particles have been considered suitable for biomedicine owing to their asymmetric structure and unique properties. Although Janus particles have been applied in biosensing for dual-mode sensing, there are almost no reports for the detection of multiple indicators. In fact, many patients require different diagnoses, such as the examination of hepatogenic diseases in diabetics. Here, a Janus particle based on SiO2 was synthesized using a Pickering emulsion method. A novel strategy for detecting glucose and alpha-fetoprotein (AFP) based on different principles using this Janus particle was then constructed as a detection platform. Composed of adjustable dendritic silica loaded with gold nanoclusters (Au NCs) and glucose oxidase (GOx) and spherical SiO2 coupled with AFP antibody, this Janus fluorescent probe achieved the double detection of glucose and AFP. With the protection of dendritic silica, the enzyme temperature stability was enhanced. Moreover, the low limit of detection for glucose (0.5 μM in PBS and 2.5 μM in serum) and AFP (0.5 ng mL-1) illustrated the feasibility of the application of the Janus material in integrated detection. This work not only supported the use of a Janus fluorescent probe as a detection platform toward glucose and AFP but also showed the potential of Janus particles in integrated detection in the future.

Simultaneous detection of two tumor markers using electrochemical immunosensor based on ultrathin metal–organic framework derived nanosheets as redox probes

Ultrathin metal–organic framework derived nanosheets (Cu/Co-UMOFNs@Au NPs) were designed for the first time as dual-catalytic multiple-label sandwich immunosensor for simultaneous detection of alpha fetoprotein (AFP) and cancer embryo antigen (CEA).

Quantitative mass spectrometric analysis of hepatocellular carcinoma biomarker alpha-fetoprotein.

Serum alpha-fetoprotein (AFP) has been used as a marker for the diagnosis of hepatocellular carcinoma (HCC) and its core fucosylation is associated with the early stage of HCC. However, current methods for the detection of AFP with core fucose are not highly accurate for early diagnosis. In this study, we established an enzyme-assisted mass spectrometric method for the quantitative analysis of AFP/core fucose with high specificity and sensitivity. We employed endoglycosidase treatment of AFP to improve the biomarker analysis. The accuracy and precision are within the US FDA-suggested value, and a good linearity (r2 = 0.9930) and a detection limit of 15.6 ng mL-1 can be achieved.

A pH-responsive hollow mesoporous SiO2 nanocarrier designed for the ultrasensitive detection of alpha-fetoprotein

A metal ion (organic small molecule)-HMSS@HA bioresponsive release system is used as a signal amplification immunosensor.