Functionalization of nanodiamond

Abstract

Combining nanoparticles and biomaterials into an integrated system for applications in drug delivery or bioanalysis has become a key research focus in nanobiotechnology. We demonstrate here the functionalization of detonation nanodiamond (ND) with aminophenylboronic acid (APBA) for the purpose of targeting the selective capture of glycoproteins from unfractionated protein mixtures. The reacted ND, after blending with the matrix consisting of alpha-cyano-4-hydroxy-cinnamic acid, could be applied directly for matrix-assisted laser desorption ionization (MALDI) assay. A loading capacity of 350 mg of glycoprotein per g of ND could be attained on ND that has been silanized with an alkyl linker chain prior to linking with the phenylboronic acid. The role of the alkyl spacer chain is to form an exclusion shell which suppresses nonspecificbinding with non-glycated proteins and to reduce steric hindrance among the bound glycoproteins. In the absence of the alkyl spacer chain, nonselective binding of proteins was obtained. This work demonstrates the usefulness of functionalized ND as a high-efficiency extraction and analysis platform for proteomics research.We also demonstrate the functionalization of nanoscale diamond with aryl organics using a classic chemistry reaction - Suzuki coupling. The efficiencies of the Suzuki coupling reaction can be further improved by performing the chemistry in a microreactor in aqueous environment (PBS) where electro-osmotic flow accelerates the mixing of reactants. Using the Suzuki coupling reactions, we can functionalize nanodiamond with trifluoroaryls and increase the solubilities of nanodiamond in ethanol and hexane. Pyrene can also be coupled via this route to generate fluorescent pyrene-nanodiamond.Lastly, we showed that alpha particles irradiation could provide a viable alternative to ion beam irradiation for creating defect centers in detonation nanodiamond. Following alpha particles irradiation and annealing at 900oC, highly fluorescent, photostable nanodiamond could be produced.