A Graphene Oxide-Based Fluorescent Biosensor for the Analysis of Peptide–Receptor Interactions and Imaging in Somatostatin Receptor Subtype 2 Overexpressed Tumor Cells

Graphene oxide assisted fluorescent chemodosimeter for high-performance sensing and bioimaging of fluoride ions

Fluorescent chemodosimeters for a fluoride ion (F(-)) based on a specifically F(-)-triggered chemical reaction are characterized by high selectivity. However, they are also subjected to intrinsic limits, such as long response time, poor stability under aqueous solution, and unpredictable cell-member penetration. To address these issues, we reported here that the self-assembly of fluorescent chemodosimeter molecules on a graphene oxide (GO) surface can solve these problems by taking advantage of the excellent chemical catalysis and nanocarrier functions of GO. As a proof of concept, a new F(-)-specific fluorescent chemodosimeter molecule, FC-A, and the GO self-assembly structure of GO/FC-A were synthesized and characterized. Fluorescent sensing and imaging of F(-) with FC-A and GO/FC-A were performed. The results showed that the reaction rate constant of GO/FC-A for F(-) is about 5-fold larger than that of FC-A, so that the response time was shortened from 4 h to about 30 min, while for F(-), the response sensitivity of GO/FC-A was >2-fold higher than that of FC-A. Furthermore, GO/FC-A showed a better bioimaging performance for F(-) than FC-A because of the nanocarrier function of GO for cells. It is demonstrated that this GO-based strategy is feasible and general, which could help in the exploration of the development of more effective fluorescent nanodosimeters for other analytes of interest.

Investigating the interaction of dye molecules with graphene oxide by using a surface plasmon resonance technique

A surface plasmon resonance technique was used to systematically study the interaction of two dye molecules with graphene oxide (GO) and electrochemically reduced GO (EC-rGO) substrates.

Chemical and magnetic functionalization of graphene oxide as a route to enhance its biocompatibility

The novel approach for deposition of iron oxide nanoparticles with narrow size distribution supported on different sized graphene oxide was reported. Two different samples with different size distributions of graphene oxide (0.5 to 7 μm and 1 to 3 μm) were selectively prepared, and the influence of the flake size distribution on the mitochondrial activity of L929 with WST1 assay in vitro study was also evaluated. Little reduction of mitochondrial activity of the GO-Fe3O4 samples with broader size distribution (0.5 to 7 μm) was observed. The pristine GO samples (0.5 to 7 μm) in the highest concentrations reduced the mitochondrial activity significantly. For GO-Fe3O4 samples with narrower size distribution, the best biocompatibility was noticed at concentration 12.5 μg/mL. The highest reduction of cell viability was noted at a dose 100 μg/mL for GO (1 to 3 μm). It is worth noting that the chemical functionalization of GO and Fe3O4 is a way to enhance the biocompatibility and makes the system independent of the size distribution of graphene oxide.