Zhide Zhou

Glypican-3 (GPC3), as an emerging biomarker, has been shown to be beneficial for the early diagnosis and treatment of hepatocellular carcinoma (HCC). In this study, an ultrasensitive electrochemical biosensor for GPC3 detection has been constructed based on the hemin-reduced graphene oxide-palladium nanoparticles (H-rGO-Pd NPs) nanozyme-enhanced silver deposition signal amplification strategy. When GPC3 specifically interacted with GPC3 antibody (GPC3_Ab) and GPC3 aptamer (GPC3_Apt), an “H-rGO-Pd NPs-GPC3_Apt/GPC3/GPC3_Ab” sandwich complex was formed with peroxidase-like properties which enhanced H₂O₂ to reduce the silver (Ag) ions in solution to metallic Ag, resulting in the deposition of silver nanoparticles (Ag NPs) on the surface of the biosensor. The amount of deposited Ag, which was derived from the amount of GPC3, was quantified by the differential pulse voltammetry (DPV) method. Under ideal circumstances, the response value was linearly correlated with GPC3 concentration at 10.0–100.0 μg/mL with R² of 0.9715. When the GPC3 concentration was in the range from 0.01 to 10.0 μg/mL, the response value was logarithmically linear with the GPC3 concentration with R² of 0.9941. The limit of detection was 3.30 ng/mL at a signal-to-noise ratio of three and the sensitivity was 1.535 μAμM⁻¹cm⁻². Furthermore, the electrochemical biosensor detected the GPC3 level in actual serum samples with good recoveries (103.78–106.52%) and satisfactory relative standard deviations (RSDs) (1.89–8.81%), which confirmed the applicability of the sensor in practical applications. This study provides a new analytical method for measuring the level of GPC3 in the early diagnosis of HCC.

In recent years, nanozymes-based sensing platforms have been attracted for their excellent performances in practical applications. Glypican-3 (GPC3) has been extensively regarded as a sensitive biomarker for hepatocellular carcinoma (HCC). In this work, the Hemin-reduced oxide graphene-platinum@palladium NPs (H-R-Pt@Pd NPs) with the peroxidase-like activity has been used to construct a facile colorimetric aptasensor for GPC3 detection. GPC3 aptamer (Apt) conjugated to the surface of H-R-Pt@Pd NPs serves as a signal probe, and GPC3 antibody (Ab) uses as a capture probe. In the presence of GPC3, it was recognized by the Ab and the Apt on the H-R-Pt@Pd NPs and initiated the formation of an H-R-Pt@Pd NPs-Apt/GPC3/Ab sandwich structure complex. Taking advantage of the excellent enzymatic catalytic properties, H-R-Pt@Pd NPs can oxidase colorless 3,3’,5,5’-tetramethylbenzidine (TMB) into blue oxTMB with the presence of H ₂ O ₂ , the absorbance of the system at 652 nm changed consequently, which realize the sensitive colorimetric detection of GPC3. In addition, the catalytic mechanism of H-R-Pt@Pd NPs was confirmed by free radical experiments to be induced by hydroxyl radicals (∙OH). Under optimal conditions, the aptasensor has a linear range of 10.0 to 300.0 ng/mL, and a limit of detection (LOD) of 5.06 ng/mL. Furthermore, the aptasensor is employed to detect GPC3 in human serum samples with the recoveries of 105.94%-116.33% and RSDs of 0.93%-3.08%. Overall, this assay possesses high selectivity and operability, and good sensitivity, indicating the potential for GPC3 detection in the field of clinical HCC diagnosis.

Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related deaths in China. Glypican-3 (GPC3) is a specific antigen related to HCC, which is widely used in clinical detection as a reliable marker of HCC. In this paper, a highly sensitive homogeneous apatasensor was designed for GPC3 detection based on fluorescence resonance energy transfer (FRET) where the GPC3 aptamer labelled gold carbon dots (AuCDs-GPC3_Apt) are used as a donor and magnetic graphene oxide (Fe₃O₄/GO) nanosheets are used as an acceptor. A one-step hydrothermal method was used to synthesize AuCDs to provide sufficient fluorescence. The FRET phenomenon exists between AuCDs-GPC3_Apt and Fe₃O₄/GO, which weakens the fluorescence intensity of the whole system. When the target GPC3 is added to the FRET system, the fluorescent AuCDs-GPC3_Apt binds to the GPC3 and forms a folded structure, which leads to AuCDs-GPC3_Apt separation from Fe₃O₄/GO nanosheets. The Fe₃O₄/GO is then magnetically separated so that the fluorescence of free labelled AuCDs-GPC3_Apt is restored. Under the optimum conditions, the fluorescence recovery rate is linearly correlated with the concentration of GPC3 (5–100 ng·mL⁻¹) and the detection limit is 3.01 ng·mL⁻¹ (S/N = 3). This strategy shows recoveries from 98.76 to 101.29% in real human serum samples and provides an immediate and effective detection method for the quantification of GPC3 with great potential applications for early diagnosis of HCC. Graphical abstract A sensitive homogeneous FRET-based apatasensor was designed for GPC3 detection where the AuCDs-GPC3_Apt is a donor and Fe₃O₄/GO nanosheets are an acceptor. The GPC3 fluorescent aptasensor combines wider output range with low cost, high specificity, and good anti-interference.