Tuesday, 30 May 2017
Grand Ballroom (Hilton New Orleans Riverside)
Graphene and its derivatives are novel materials with a number of unique properties that can be applied in electronics, sensing and biotechnology. Particularly, graphene oxide (GO) is an exceptional system that, unlike graphene, can be chemically mass-produced at low cost and possesses physical properties that are critical for biomedical applications. GO exhibits pH-dependent fluorescence emission in the visible/near-infrared, providing a possibility of molecular imaging and pH-sensing. It is also water soluble and has a substantial platform for functionalization, which allows for the delivery of multiple therapeutics, or the attachment of different sensing moieties. Some of these properties can be adjusted by the means of chemical/physical processing to fit the desired therapeutic delivery or sensing approaches. We utilize and modify these properties to yield a multifunctional delivery/imaging/sensing platform geared toward the analysis of cancer therapeutics delivery in vitro. In our work GO serves as a drug transport agent when paired with cancer therapeutic drugs and as a molecular marker for imaging the delivery pathways. The optimal emission and excitation of the graphene oxide flakes are selected to maximize the imaging modality in the spectrally-confined region and reduce the effects of biological autofluorescence. We also modify GO physical properties via controlled oxidation to maximize the emission and reduce the cytotoxicity to low/negligible levels: we report over 90% cell viability with GO concentration levels of 15 ug/mL based on the MTT assay in HEK-293 cells. GO emission in healthy (HEK-293) and cancer (HeLa) cells is quantified for a variety of pH environments, as well as flake sizes, to identify the ideal conditions for cellular internalization and pH-sensing of acidic cancerous environments. In addition, in-vitro fluorescence microscopy analysis provide quantitative assessment of the drug delivery and preferential targeting for cancer versus healthy cells. The results of this work suggest GO as an innovative and effective multifunctional platform for cancer therapeutics.