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

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.

Sandwich-type electrochemical immunosensor based on Au NPs/3D hierarchical porous carbon network and Au NPs/Cu9S8 nanocages for the detection of alpha-fetoprotein

Alpha-fetoprotein (AFP), serves as a reliable and vital biomarker for precise diagnosis and effective monitoring of hepatocellular carcinoma, requires precise detection. Herein, a sandwich-structured electrochemical immunosensor was crafted, employing three-dimensional layered porous carbon modified with gold nanoparticles (Au NPs) as the substrate and Au NPs/Cu9S8 as the labeling compound for accurate and sensitive detection of AFP. Due to the effective coordination between the 3D carbon network, Au NPs, and hollow Cu9S8 nanocubes, the sandwich-structured electrochemical immunosensor was able to produce three distinct response signals via various detection techniques, demonstrating a broad linear range (0.0001-400 ng/mL), exceptional sensitivity, and a remarkably low detection limit of 2.63 fg/mL. Moreover, the constructed immunosensor could be used to detect AFP in human serum. This research may offer a novel material framework for developing highly sensitive immunosensors.

Electrochemical immuno-biosensors for the detection of the tumor marker alpha-fetoprotein: A review

Alpha-fetoprotein (AFP) is a glycoprotein that has many important physiological functions, including transportation, immunosuppression, and induction of apoptosis by T lymphocytes. AFP is closely related to the development of hepatocellular carcinoma and many kinds of tumors, all of which can show high concentrations, so it is used as a positive test indicator for many kinds of tumors. This paper reviews recent advances in the detection of the tumor marker AFP based on three immuno-biosensors: electrochemical (EC), photoelectrochemical (PEC), and electrochemical luminescence (ECL). The electrodes are modified by different materials or homemade composites, different signaling molecules are selected as single probes or dual probes for the detection of AFP. The detection limit was as low as 3 fg/mL, which indicated that the AFP immunosensor had achieved highly sensitive detection. In addition, we also reviewed and summarized the current development status and application prospect of AFP immunoelectrochemical sensors. There are not too many researches on immunosensors based on dual-signal ratios, and the commonly used probes are methylene blue (MB) and ferrocene (Fc). It would be more innovative to have more novel signaling molecules as probes to prepare dual-signal ratio sensors.

A novel microfluidic chip integrating with microcolumn array electrodes for rapid and ultrasensitive detection of alpha-fetoprotein

BACKGROUND

Cancer posed a serious threat to human health, and early diagnosis of cancer biomarker was extremely important for the treatment and control of cancer. Electrochemistry-based assays were low-cost, responsive and easy to operate, but there were some challenges in terms of accuracy, detection limit, efficiency and portability. The combination of microfluidic devices and electrochemical methods was expected to construct a high-performance sensing platform, but long-time antigen-antibody incubation was still required. Therefore, a novel microfluidic chip needs to be developed, which has the advantages of good portability, short incubation time, high accuracy, low detection limit and great application to point-of-care testing.

RESULTS

A microfluidic sensor based on microcolumn array electrodes was developed, in which microcolumns could create local mixed flow to reduce the incubation time of target molecules and enhance their interaction with the sensing interface. Besides, three dimensional Mxene fibers-gold nanoparticles (3D MF-Au) was modified on the microcolumn array electrodes to increase active sites and provide more electrolyte shuttle holes. The electrolyte turbulence caused by the microcolumn array electrodes could heighten the contact between the target molecules and sensing interface and accelerate the transfer of redox pairs, thus reducing the incubation time of the target molecules and improving the electrochemical responses in synergy with the 3D MF-Au. Herein, the detection of AFP was chosen as a model, and the microfluidic sensor possessed superior performance for analysis of AFP in the range of 0.1 pg mL-1 - 200 ng mL-1 with a low detection limit (LOD) of 0.0648 pg mL-1.

SIGNIFICANCE

This microfluidic chip integrating with microcolumn array electrodes has been successfully implemented to detect AFP in human serum, and the results were consistent with that of electrochemical chemiluminescence method. The microfluidic chip provided a new strategy of portability, shortening incubation time and enhancing electrical signals for antigen detection of real samples, which showed great utilization potentiality in point-of-care testing.

Construction of a Dual-Mode Immune Platform Based on the Photothermal Effect of AgCo@NC NPs for the Detection of α-Fetoprotein

Compared with the accuracy of a single signal and the limitation of environmental applicability, the application value of dual-mode detection is gradually increasing. To this end, based on the photothermal effect of Ag/Co embedded N-rich mesoporous carbon nanomaterials (AgCo@NC NPs), we designed a dual-mode signal response system for the detection of α-fetoprotein (AFP). First, AgCo@NC NPs act as a photothermal immunoprobe that converts light energy into heat driven by a near-infrared (NIR) laser and obtains temperature changes corresponding to the analyte concentration on a hand-held thermal imager. In addition, this temperature recognition system can significantly improve the efficiency of Fenton-like reactions. AgCo@NC NPs act as peroxidase mimics to initiate the generation of poly N-isopropylacrylamide (PNIPAM, resistance enhancer) by cascade catalysis and the degradation of methylene blue (MB), thus enabling electrochemical testing. The dual-mode assay ranges from 0.01 to 100 and 0.001-10 ng/mL, with lower limits of detection (LOD) of 3.2 and 0.089 pg/mL, respectively, and combines visualization, portability, and high efficiency, opening new avenues for future clinical diagnostics and inhibitor studies.