A fluorescence aptasensor based on GSH@GQDs and RGO for the detection of Glypican-3

Glypican-3 (GPC3), a heparin sulfate proteoglycan, is a potential diagnostic and therapeutic target for hepatocellular carcinoma. In this paper, a novel fluorescent aptasensor for GPC3 detection is constructed via [email protected] quantum dots–labeled GPC3 aptamer ( [email protected] Apt ) as a fluorescence probe. First, [email protected] is screened out with higher fluorescence intensity, which emits bright blue fluorescence under ultraviolet light. Then, the fluorescence-labeled [email protected] Apt probe is formed by the combination of amination GPC3 Apt and [email protected] using EDC/NHS coupled reaction. Under hydrogen bond and π-π interaction/stacking, the fluorescence of [email protected] Apt could be quenched by reductive graphene oxide (RGO) with the help of the photoinduced electron transfer and the fluorescence resonance energy transfer mechanism. In the presence of GPC3, the [email protected] Apt specifically recognizes and binds to GPC3, giving rise to the change of secondary structure of GPC3 Apt to form the GPC3/GPC3 Apt [email protected] complex, which would lead to the disintegration of the [email protected] Apt -RGO compound. Therefore, the energy transfer process is blocked and the fluorescence intensity is restored, enabling a highly sensitive response to GPC3. When the concentration of GPC3 is from 5.0 ng/mL to 150.0 ng/mL, the fluorescence recovery rate is well linearly related to GPC3 concentration with the limit of detection of 2.395 ng/mL (S/N = 3). This strategy shows recoveries from 98.31% to 101.89% in human serum samples and provides simple, fast and cheap analysis of GPC3, which suggests that it has great potential applications in clinical diagnosis for hepatocellular carcinoma.