Metal Nanoparticles/MoS₂ Surface-Enhanced Raman Scattering-Based Sandwich Immunoassay for α-Fetoprotein Detection

Abstract

The detection of cancer biomarkers at an early stage of tumor development is vital for effective diagnosis and treatment of cancer. Current diagnostic tools can often detect cancer only when the biomarker levels are already too high, so that the tumors have spread and treatments are less effective. It is urgent therefore to develop highly sensitive assays for the detection of such biomarkers at the lowest possible concentration. In this context, we developed a sandwich immunoassay based on surface-enhanced Raman scattering (SERS) for the ultrasensitive detection of α-fetoprotein (AFP), which is typically present in human serum as a biomarker indicative of early stages of hepatocellular carcinoma. In the immunoassay design, molybdenum disulfide (MoS2) modified with a monoclonal antibody was used as a capture probe for AFP. A secondary antibody linked to an SERS-encoded nanoparticle was employed as the Raman signal reporter, that is, the transducer for AFP detection. The sandwich immunocomplex “capture probe/target/SERS tag” was deposited on a silicon wafer and decorated with silver-coated gold nanocubes to increase the density of “hot spots” on the surface of the immunosensor. The developed SERS immunosensor exhibits a wide linear detection range (1 pg mL–1 to 10 ng mL–1) with a limit of detection as low as 0.03 pg mL–1 toward AFP with good reproducibility (RSD < 6%) and stability. These parameters demonstrate that the proposed immunosensor has the potential to be used as an analytical platform for the detection of early-stage cancer biomarkers in clinical applications.

Electrochemical α-fetoprotein immunosensor based on Fe3O4NPs@covalent organic framework decorated gold nanoparticles and magnetic nanoparticles including SiO2@TiO2

“…The validity of the electrochemical AFP immunosensor was evaluated by SERS [60] and when the comparison results (Table S2) were investigated, there was no important difference between the two methods (T calculated > T tabulated , p > 0.05).…”

Raman Scattering-Based Biosensing: New Prospects and Opportunities

“…The implementation of multicomposites based on several types of nanoparticles in combination with a Raman reporter molecule made it possible to obtain a multilayer structure. The presence of nanosized cubes of Au–Ag on the surface of a silicon wafer made it possible to increase the number of “hot spots” and to improve the detection limit of alpha-fetoprotein in a sandwich immunoassay to levels [ 110 ].…”

“…The choice of antibodies is preferable because it allows high-affinity specific binding to the target analyte [ 151 ]. SERS-based immunoassay techniques are described to determine bacteria [ 152 ], viruses [ 153 ], immunoglobulins [ 154 ], cancer biomarkers [ 110 , 155 , 156 ], infection diseases [ 157 ], and so on.…”

Application of Surface-Enhanced Raman Spectroscopy in the Screening of Pulmonary Adenocarcinoma Nodules

“…Surface-enhanced Raman spectroscopy (SERS) is an enhancement effect on the surface of nanosized metal structures, which can escalate the intensity of ordinary Raman scattering by several orders of magnitude, even to the level of single-molecule detection. SERS has the advantages of high sensitivity, fast detection speed, low cost, and strong versatility and has been widely used in many fields such as biomedicine [ 12 ], drug detection, and bacterial detection [ 13 ]. The serum is composed of water, carbohydrates, proteins, and other components.…”