Development of highly sensitive techniques for cancer detection can increase survival rates due to early detection. Fluorescent high pressure, high temperature (HPHT) nanodiamonds with nitrogen vacancy centers (NVC) represents an emerging fluorophore that has the potential to lead to new oncological advancements. NDs are attractive for biolabelling due to their chemical inertness and lack of cytotoxicity, as well as the magnetic and electric field sensing properties of the nitrogen vacancy center. Here we use gas phase and wet chemical techniques to modify the surface with amines and thin shells of SiO<sub>2</sub> for biolabelling purposes. Our goal is to increase the chemical reactivity of the inert diamond surface and probe new routes for functionalization. We confirm the ND surface moieties using overlapping spectroscopies based on laboratory (FTIR) and synchrotron based techniques (NEXAFS and XPS). Polyethylene glycol and amine moieties were grafted onto the ND surface for stabilization and bioconjugation in cell media, respectively. The amine moieties were then used as a molecular anchor for conjugation of a small molecule library that has been previously shown to differentiate cancer cell types and cellular metabolic states. Cellular uptake of the ND probe was confirmed via fluorescence confocal microscopy and is understood to take place due to multivalent interactions at the cell surface. Our work is promising for both the fundamental surface science of diamond surfaces and their applied use in biolabelling modalities based on the nitrogen vacancy center.

Surface modification of nanoscale diamond for biolabelling with the nitrogen vacancy center

253rd National Meeting (2017)

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