Size-reduction of nanodiamonds via air oxidation

Gaebel, T.; Bradac, Carlo; Chen, J.; Say, Jana M.; Brown, Louise J.; Hemmer, Philip; Rabeau, James R.

doi:10.1016/j.diamond.2011.09.002

Cited by 85 publications

(64 citation statements)

References 26 publications

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“…3. To properly compare the calculated results with the experimentally measured data, it has to be noted that the oxidation process would reduce the size of NDs, as reported by T. Gaeble et al 32 The as-received NDs used in this work have a size distribution ranging from 0 to 50 nm. After the oxidation treatment, the d max reduced to about 40 nm and the most probable diameter was about 20 nm.…”

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confidence: 77%

A statistical correlation investigation for the role of surface spins to the spin relaxation of nitrogen vacancy centers

et al. 2014

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We investigated the influence of spins on surface of nanodiamonds (NDs) to the longitudinal relaxation time (T1) and transverse relaxation time (T2) of nitrogen vacancy (NV) centers in ND. A spherical model of the NDs was suggested to account for the experimental results of T1 and T2, and the density of surface spins was roughly estimated based on the statistical analysis of experimental results of 72 NDs containing a single NV center. For NDs studied here, the T1 of NV center inside is highly dependent to the surface spins of the NDs. However, for the T2 of NV center, intrinsic contributions must be much pronounced than that by surface spins. In other words, T1 of an NV center in NDs is more sensitive to the change of the surface spin density than T2.

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confidence: 77%

A statistical correlation investigation for the role of surface spins to the spin relaxation of nitrogen vacancy centers

et al. 2014

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“…9,10 To control aggregation and ensure long-term stability of ND dispersions, chemical modification of the surface can be utilized. [11][12][13] Rational functionalization of ND surfaces with different moieties to serve multiple purposes is a relatively new approach. For example, functional groups can be grafted to simultaneously counter aggregation and facilitate binding with small chemical molecules or biomolecules with a purpose to serve as drug, protein, and gene carriers.…”

Section: Introductionmentioning

confidence: 99%

Lysine-functionalized nanodiamonds as gene carriers: development of stable colloidal dispersion for in vitro cellular uptake studies and siRNA delivery application

Alwani¹,

Kaur²,

Michel³

et al. 2016

IJN

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Purpose Nanodiamonds (NDs) are emerging as an attractive tool for gene therapeutics. To reach their full potential for biological application, NDs should maintain their colloidal stability in biological milieu. This study describes the behavior of lysine-functionalized ND (lys-ND) in various dispersion media, with an aim to limit aggregation and improve the colloidal stability of ND-gene complexes called diamoplexes. Furthermore, cellular and macromolecular interactions of lys-NDs are also analyzed in vitro to establish the understanding of ND-mediated gene transfer in cells. Methods lys-NDs were synthesized earlier through covalent conjugation of lysine amino acid to carboxylated NDs surface generated through re-oxidation in strong oxidizing acids. In this study, dispersions of lys-NDs were prepared in various media, and the degree of sedimentation was monitored for 72 hours. Particle size distributions and zeta potential measurements were performed for a period of 25 days to characterize the physicochemical stability of lys-NDs in the medium. The interaction profile of lys-NDs with fetal bovine serum showed formation of a protein corona, which was evaluated by size and charge distribution measurements. Uptake of lys-NDs in cervical cancer cells was analyzed by scanning transmission X-ray microscopy, flow cytometry, and confocal microscopy. Cellular uptake of diamoplexes (complex of lys-NDs with small interfering RNA) was also analyzed using flow cytometry. Results Aqueous dispersion of lys-NDs showed minimum sedimentation and remained stable over a period of 25 days. Size distributions showed good stability, remaining under 100 nm throughout the testing period. A positive zeta potential of >+20 mV indicated a preservation of surface charges. Size distribution and zeta potential changed for lys-NDs after incubation with blood serum, suggesting an interaction with biomolecules, mainly proteins, and a possible formation of a protein corona. Cellular internalization of lys-NDs was confirmed by various techniques such as confocal microscopy, soft X-ray spectroscopy, and flow cytometry. Conclusion This study establishes that dispersion of lys-NDs in aqueous medium maintains long-term stability and also provides evidence that lysine functionalization enables NDs to interact effectively with the biological system to be used for RNAi therapeutics.

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“…One possible etching mechanism is high-temperature surface graphitization 14,15 that would reduce the volume fraction of diamond in the nanoparticle and that has been previously observed in diamond annealed under conditions similar to our experiment. 23 To verify the presence of surface graphite, Raman spectroscopy was performed on samples prepared in this work. Figure 5 shows Raman spectra from three different substrates: a bare Si substrate, a Si substrate with drop-cast nanodiamonds treated with TEOS, and a post-annealed nanodiamond-coated Si substrate used in this study.…”

confidence: 99%

In situ study of annealing-induced strain relaxation in diamond nanoparticles using Bragg coherent diffraction imaging

et al. 2017

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We observed changes in morphology and internal strain state of commercial diamond nanocrystals during high-temperature annealing. Three nanodiamonds were measured with Bragg coherent x-ray diffraction imaging, yielding three-dimensional strain-sensitive images as a function of time/temperature. Up to temperatures of 800 °C, crystals with Gaussian strain distributions with a full-width-at-half-maximum of less than 8×10−4 were largely unchanged, and annealing-induced strain relaxation was observed in a nanodiamond with maximum lattice distortions above this threshold. X-ray measurements found changes in nanodiamond morphology at temperatures above 600 °C that are consistent with graphitization of the surface, a result verified with ensemble Raman measurements.

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Size-reduction of nanodiamonds via air oxidation

Cited by 85 publications

References 26 publications

A statistical correlation investigation for the role of surface spins to the spin relaxation of nitrogen vacancy centers

A statistical correlation investigation for the role of surface spins to the spin relaxation of nitrogen vacancy centers

Lysine-functionalized nanodiamonds as gene carriers: development of stable colloidal dispersion for in vitro cellular uptake studies and siRNA delivery application

In situ study of annealing-induced strain relaxation in diamond nanoparticles using Bragg coherent diffraction imaging

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