Robust fluorescence sensing platform for detection of CD44 cells based on graphene oxide/gold nanoparticles

•Fluorescence detection system to detect CD44 on the surface of cancer cells.•TAMRA-labeled CD44 aptamer based on graphene oxide (GO)/gold nanoparticles (AuNPs).•Specificity, sensitivity, selectivity, and ease of use.•Detection limits of 1 × 101 CFU/mL.•The fluorescence diagnosis using signal-to-background ratio enhancer to detect cancer cells.

Gold-coated graphene oxide hybrid material (GO/AuNPs) has exceptional physical and chemical properties like π–π stacking interaction and plays a role in quencher of fluorescence dye. Therefore, GO/AuNPs could enhance the signal-to-background ratio with fluorescence dye that was the point in this fluorescent biosensor. In this study, tetramethyl-6-carboxy-rhodamine (TAMRA)-labeled aptamers that specifically interact with the hyaluronic acid binding domain of CD44 were used as targets to investigate the applicability of the method. GO/AuNPs–TAMRA-aptamer complexes could detect CD44 target cancer cells within a concentration range of 1 × 101 to 1 × 107 CFU/mL. A linear relationship was observed between target cell concentration and relative fluorescence intensity. The more mounted up CD44 target cell concentrations, relative fluorescence intensity of GO/AuNPs–TAMRA-aptamer complexes was increased even more, which was superior to that of GO alone. Sensitivity of the detection system displayed a low detection limit of 1 × 101 CFU/mL. Additionally, this method is specific in that fluorescence is not much enhanced in CD44 negative cancer cell line. Thus, the fluorescence sensing based on GO/AuNPs could be developed to receptive and robust detection tool for various target molecules.

Graphical abstractGO/AuNPs were applied for the excellent signal-to-background ratio enhancer based on fluorescence quenching effect and interaction between TAMRA-labeled CD44 aptamers and CD44 targets.Figure optionsDownload full-size imageDownload as PowerPoint slide