General Method to Increase Carboxylic Acid Content on Nanodiamonds
Ganesh Shenoy,
Jessica Ettedgui,
Chandrasekhar Mushti,
Jennifer Hong,
Kelly Lane,
Burchelle Blackman,
Hak-Sung Jung,
Yasuharu Takagi,
Yeonee Seol,
Martin Brechbiel,
Rolf E. Swenson,
Keir C. Neuman
Affiliations
Ganesh Shenoy
Laboratory of Single Molecule Biophysics, National Heart Lung and Blood Institute, National Institutes of Health, Building 50, Room 2134, Bethesda, MD 20892, USA
Jessica Ettedgui
Chemistry and Synthesis Center, National Heart Lung and Blood Institute, National Institutes of Health, Building B, Room 3040, 9800 Medical Center Drive, Rockville, MD 20850, USA
Chandrasekhar Mushti
Chemistry and Synthesis Center, National Heart Lung and Blood Institute, National Institutes of Health, Building B, Room 3040, 9800 Medical Center Drive, Rockville, MD 20850, USA
Jennifer Hong
Laboratory of Single Molecule Biophysics, National Heart Lung and Blood Institute, National Institutes of Health, Building 50, Room 2134, Bethesda, MD 20892, USA
Kelly Lane
Chemistry and Synthesis Center, National Heart Lung and Blood Institute, National Institutes of Health, Building B, Room 3040, 9800 Medical Center Drive, Rockville, MD 20850, USA
Burchelle Blackman
Chemistry and Synthesis Center, National Heart Lung and Blood Institute, National Institutes of Health, Building B, Room 3040, 9800 Medical Center Drive, Rockville, MD 20850, USA
Hak-Sung Jung
Laboratory of Single Molecule Biophysics, National Heart Lung and Blood Institute, National Institutes of Health, Building 50, Room 2134, Bethesda, MD 20892, USA
Yasuharu Takagi
Laboratory of Single Molecule Biophysics, National Heart Lung and Blood Institute, National Institutes of Health, Building 50, Room 2134, Bethesda, MD 20892, USA
Yeonee Seol
Laboratory of Single Molecule Biophysics, National Heart Lung and Blood Institute, National Institutes of Health, Building 50, Room 2134, Bethesda, MD 20892, USA
Martin Brechbiel
Radiation Oncology Branch, National Cancer Institute, National Institutes of Health, Building 10, Room B3B69, Bethesda, MD 20892, USA
Rolf E. Swenson
Chemistry and Synthesis Center, National Heart Lung and Blood Institute, National Institutes of Health, Building B, Room 3040, 9800 Medical Center Drive, Rockville, MD 20850, USA
Keir C. Neuman
Laboratory of Single Molecule Biophysics, National Heart Lung and Blood Institute, National Institutes of Health, Building 50, Room 2134, Bethesda, MD 20892, USA
Carboxylic acid is a commonly utilized functional group for covalent surface conjugation of carbon nanoparticles that is typically generated by acid oxidation. However, acid oxidation generates additional oxygen containing groups, including epoxides, ketones, aldehydes, lactones, and alcohols. We present a method to specifically enrich the carboxylic acid content on fluorescent nanodiamond (FND) surfaces. Lithium aluminum hydride is used to reduce oxygen containing surface groups to alcohols. The alcohols are then converted to carboxylic acids through a rhodium (II) acetate catalyzed carbene insertion reaction with tert–butyl diazoacetate and subsequent ester cleavage with trifluoroacetic acid. This carboxylic acid enrichment process significantly enhanced nanodiamond homogeneity and improved the efficiency of functionalizing the FND surface. Biotin functionalized fluorescent nanodiamonds were demonstrated to be robust and stable single-molecule fluorescence and optical trapping probes.
