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Targeting fluorescent nanodiamonds to vascular endothelial growth factor receptors in tumor
摘要： The increased expression of vascular endothelial growth factor (VEGF) and its receptors is associated with angiogenesis in a growing tumor, presenting potential targets for tumor-selective imaging by way of targeted tracers. Though fluorescent tracers are used for targeted in vivo imaging, the lack of photostability and biocompatibility of many current fluorophores hinder their use in several applications involving long-term, continuous imaging. To address these problems, fluorescent nanodiamonds (FNDs), which exhibit infinite photostability and excellent biocompatibility, were explored as fluorophores in tracers for targeting VEGF receptors in growing tumors. To explore FND utility for imaging tumor VEGF receptors, we used click-chemistry to conjugate multiple copies of an engineered single-chain version of VEGF site-specifically derivatized with trans-cyclooctene (scVEGF-TCO) to 140 nm FND. The resulting targeting conjugates, FND-scVEGF, were then tested for functional activity of the scVEGF moieties through biochemical and tissue culture experiments and for selective tumor uptake in Balb/c mice with induced 4T1 carcinoma. We found that FND-scVEGF conjugates retain high affinity to VEGF receptors in cell culture experiments and observed preferential accumulation of FND-scVEGF in tumors relative to untargeted FND. Microspectroscopy provided unambiguous determination of FND within tissue by way of the unique spectral shape of nitrogen-vacancy induced fluorescence. These results validate and invite the use of targeted FND for diagnostic imaging and encourage further optimization of FND for fluorescence brightness.
关键词： Vascular Endothelial Growth Factor,Oncology,Targeted Fluorescence Imaging,Nanodiamond,Angiogenesis
更新于2025-11-21 11:24:58
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Hybrids made of defective nanodiamonds interacting with DNA nucleobases
摘要： The characteristics of hybrids made of a defective nanodiamond and a biomolecule unit are investigated in this work. Focus is given on the interaction between the nanodiamond and a DNA nucleobase. The latter is placed close to the former in two different arrangements, realizing different bonding types. The nanodiamond includes a negatively charged nitrogen-vacancy center and is hydrogen terminated. Using quantum-mechanical calculations, we could elucidate the structural and electronic properties of such hybrids. Our study clearly identifies the importance of the relative orientation of the two components, the nanodiamond and the nucleobase, in the complex in controlling the electronic properties of the resulting hybrid. The position of the defect at the center or closer to its interface with the nucleobase further controls the electronic orbitals around the defect center, hence its optical activity. In the end, we discuss the relevance of our work in biosensing.
关键词： electronic structure,defects,DFT,DNA,nanodiamond
更新于2025-09-23 15:22:29
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Carbon Nanomaterials for Bioimaging, Bioanalysis, and Therapy || Functionalized Carbon Nanomaterials for Drug Delivery
摘要： Chemical functionalization of nanomaterials is important to control their physical properties. Since their applications frequently require the homogeneity in the physical properties of the components, many precise functionalization methods for nanomaterials have been developed in view of their applications from electronics and optics to biomedicine. Nanomedicine has been attracting growing interest in terms of therapy and diagnosis, or so called theranostics. In the field, nanomaterials play a key role and hence they are chemically functionalized frequently to meet the requirements for the purpose. In the nanomaterial‐based drug delivery system (DDS), for example, the following functions are required: the nanodrug has to disperse well in the blood to avoid embolism; circulate throughout the body to avoid leaking from the pores in the blood vessel and trapping in the reticuloendothelial system; accumulate in the targeting organ or tissue; and finally, release the loaded drug. Among the nanomaterials in the DDS, carbon nanomaterials have the following characteristic properties: (i) basically inert, but functionizable at the functional groups such as carboxylic and hydroxyl ones on the surface, edge, and defect through organic transformation; (ii) variety of options in terms of shapes including zero‐dimensional (0D, fullerenes), one‐dimensional (1D, carbon nanotubes, CNTs), two‐dimensional (2D, graphene, G), and three‐dimensional (3D, nanodiamond, ND); (iii) commercially available; and (iv) fluorescence emission from semiconducting SWNTs, relatively small size graphenes and color center in ND. The carbon nanomaterials discussed in this chapter are graphene (Section 10.2) and ND (Sections 10.3 and 10.4). Graphene has a flat and hydrophobic surface consisting of sp2 carbons. It exhibits high affinity to the flat molecules, including π‐electrons such as triphenylene, as we reported quite recently. Therefore, it has been utilized as carrier for anti‐cancer drugs with flat and hydrophobic properties. In addition, it can work as photosensitizer in photothermal therapy, making it more fascinating as a bifunctional material in cancer therapy. However, the graphene‐based carriers that have been used so far are graphene oxide (GO), because the carrier is required to have sufficient dispersibility in a physiological environment. The direct use of pristine graphene as a drug carrier, which will be described below, is the first example, as far as we know. On the other hand, ND has been reported to be low toxicity or even nontoxic nanomaterial. It is composed of the curved surface and core, not the flat surface and edge for graphene. As in the case of edge and defect in graphene, the ND surface is covered with various functional groups such as carboxylic and hydroxyl groups. Although ND is categorized as an inorganic nanomaterial due to its robustness and chemical stability, the surface functionalities impart the organic characteristics to ND, enabling the control of the physical property by controlling the surface functionality. Recently, surface chemical functionalization of ND has been actively investigated in view of its applications. In this chapter (Sections 10.3 and 10.4), chemical functionalization on ND for drug carrier will be described; the requisite functions of aqueous dispersibility, targeting specificity, and cytotoxicity are imparted to ND through stepwise surface chemical functionalization. This chapter covers synthesis, characterization, and evaluation of the following three nanodrugs: chlorin e6 (Ce6)‐loaded graphene for cancer phototherapy; Pt drug‐loaded nanodiamond for cancer chemotherapy; and DNA‐loaded nanodiamond for gene therapy.
关键词： nanodiamond,functionalization,drug delivery,graphene,phototherapy,chemotherapy,carbon nanomaterials,gene therapy
更新于2025-09-23 15:22:29
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Characterization and Formation Mechanism of the Nanodiamond Synthesized by A High Energy Arc-Plasma
摘要： A new fabrication strategy using thermal source of DC arc-discharge plasma is developed in the synthesis of nanodiamond particles. In the fabrication process, a solid mixture of Ni/Si/graphite coarse powders is used as the raw materials, meanwhile the gaseous mixture of H2/Ar served as the preparation atmosphere. The well-established arc-discharge plasma is significant in operation under a low gaseous pressure and an acceptable energy condition, and would be potential to become a novel process for synthesis of nanodiamond particles in large scale. The initially formed SiC clusters and the solid solution of Ni(C) particles are crucial in serving as crystal nuclei of diamond and an in situ carbon source which can gradually be released with cooling, respectively. Structural characterizations by high resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), Raman spectra, and X-ray diffraction (XRD) confirm the existence nanodiamond particles, they are typically spherical with 5–20 nm in size. The formation of such nanodiamond particles by the arc-discharge thermal source is discussed in detail on the knowledge of binary phase diagram, constitution of raw materials, and nucleation/growth processes under the experimental conditions.
关键词： formation mechanism,synthesis,nanodiamond,DC arc-discharge plasma
更新于2025-09-23 15:21:21
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Absorption spectra of nanodiamond aqueous dispersions by optical absorption and optoacoustic spectroscopies
摘要： The multispectral modality and technique for optically dense samples of optoacoustic spectroscopy were applied to measure spectra and high absorbances of concentrated aqueous dispersions of undoped nanodiamonds. The data from optoacoustic and optical transmission measurements and DSC data of the mean particle size by the Gibbs–Kelvin equation are compared to estimate the difference in composition of various nanodiamond trademarks. Optoacoustic spectra confirm the contribution of surface dimer chains into the absorption of nanodiamonds in the long wavelength range. Optoacoustic and conventional absorption spectra of aqueous solutions of nanodiamond fractions after centrifugation (15 300g) and ultracentrifugation (130 000g) revealed a separation of a highly absorbing non-diamond sp2 phase. The two-step separation by ultracentrifugation followed by extra centrifugation made it possible to isolate a highly absorbing and soluble nanodiamond phase with the particle size of 3.6 nm, showing a change in spectra compared to the starting nanodiamond material.
关键词： nanodiamond aqueous dispersions,nanodiamonds,optically dense samples,nanodiamond fractionation,optoacoustic spectroscopy,multispectral optoacoustic spectroscopy
更新于2025-09-23 15:21:01
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Strongly inhomogeneous distribution of spectral properties of silicon-vacancy color centers in nanodiamonds
摘要： The silicon-vacancy (SiV) color center in diamond is a solid-state single photon emitter and spin quantum bit suited as a component in quantum devices. Here, we show that SiV centers in nanodiamonds exhibit a strongly inhomogeneous distribution with regard to the center wavelengths and linewidths of the zero-phonon-line (ZPL) emission at room temperature. We find that the SiV centers separate in two clusters: one group exhibits ZPLs with center wavelengths within a narrow range ≈730–742 nm and broad linewidths between 5 and 17 nm, whereas the second group comprises a very broad distribution of center wavelengths between 715 and 835 nm, but narrow linewidths from below 1 up to 4 nm. Supported by ab initio Kohn–Sham density functional theory calculations we show that the ZPL shifts of the first group are consistently explained by strain in the diamond lattice. Further, we suggest, that the second group showing the strongly inhomogeneous distribution of center wavelengths might be comprised of a new class of silicon-related defects. Whereas single photon emission is demonstrated for defect centers of both clusters, we show that emitters from different clusters show different spectroscopic features such as variations of the phonon sideband spectra and different blinking dynamics.
关键词： diamond,single photons,density functional theory calculations,color centers,optical emission,nanodiamond
更新于2025-09-19 17:15:36
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Atomic structure of nanodiamond and its evolution upon annealing up to 1200?°C: Real space neutron diffraction analysis supported by MD simulations
摘要： Lattice strain, crystallite shape and the crystallite size distribution in nanocrystalline diamond were determined from powder diffraction data. The data were analysed by the direct space PDF method in combination with Molecular Dynamics simulations. Experimental Pair Distribution Functions were obtained from the large Q neutron diffraction data. Lattice strains were determined by comparison of the atomic pair distances at different length scales. The experimental pair-distance data were matched against the Molecular Dynamics models of diamond nanograins. Lattice relaxation at the surface and in the bulk of the simulated nanodiamond grains varied with their shape and size. Comparison of the model data to the experimentally determined strain characteristics yielded accurate information on the structure of the actual nanodiamond powders. In the as-synthesized nanodiamond the grains are polyhedrons predominantly terminated by (100) and (111) surfaces. Upon annealing the (111) surfaces with one dangling bond per atom graphitize and transform into surfaces with three dangling bond per-atom. In the samples annealed at 1200oC all grains are octahedrons terminated only by three dangling bond (111) surfaces. The mechanism of the atom rearrangement during the transformation of the (111) diamond surface into a graphite double-sheet was proposed.
关键词： graphitization,atomic structure,molecular dynamics,nanodiamond
更新于2025-09-19 17:15:36
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Femtosecond Laser-Induced Electron Emission from Nanodiamond-Coated Tungsten Needle Tips
摘要： We present femtosecond laser-induced electron emission from nanodiamond-coated tungsten tips. Based on the shortness of the femtosecond laser pulses, electrons can be photoexcited for wavelengths from the infrared (1932 nm) to the ultraviolet (235 nm) because multiphoton excitation becomes efficient over the entire spectral range. Depending on the laser wavelength, we find different dominant emission channels identified by the number of photons needed to emit electrons. Based on the band alignment between tungsten and nanodiamond, the relevant emission channels can be identified as specific transitions in diamond and its graphitic boundaries. It is the combination of the character of initial and final states (i.e., bulk or surface-near, direct or indirect excitation in the diamond band structure), the number of photons providing the excitation energy, and the peak intensity of the laser pulses that determines the dominant excitation channel for photoemission. A specific feature of the hydrogen-terminated nanodiamond coating is its negative electron affinity that significantly lowers the work function and enables efficient emission from the conduction band minimum into vacuum without an energy barrier. Emission is stable for bunch charges of up to 400 electrons per laser pulse. We infer a normalized emittance of <0.20 nm rad and a normalized peak brightness of >1.2 × 1012 A m?2 sr?1. The properties of these tips are encouraging for their use as laser-triggered electron sources in applications such as ultrafast electron microscopy as well as diffraction and novel photonics-based laser accelerators.
关键词： nanodiamond,ultrafast electron microscopy,tungsten tips,multiphoton excitation,electron emission,negative electron affinity,femtosecond laser
更新于2025-09-16 10:30:52
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Large‐Scale Fabrication of Highly Emissive Nanodiamonds by Chemical Vapor Deposition with Controlled Doping by SiV and GeV Centers from a Solid Source
摘要： A new strategy to produce loose chemical vapor deposited nanodiamonds (ND) without the need of a seeded substrate, and that are intentionally doped by silicon vacancy and GeV centers from a solid source is presented. The addition of a low amount of gases such as N2 or O2 during growth is used as a control knob to finely tune the emission intensity of embedded color centers. NDs with a high brightness and a controllable amount of group IV color centers are eventually obtained. Their optical properties at low temperature indicate that this approach can usefully produce dispersed NDs that can deliver suitable optical performance for quantum technologies.
关键词： nanodiamond,color centers,quantum technologies,spectroscopy,chemical vapor deposition
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Light and Slow-Neutron Diffraction Properties of Holographic Nanodiamond Composite Gratings
摘要： Photopolymerizable nanoparticle-polymer composite (NPC) is a photonic nanocomposite material consisting of photopolymer uniformly dispersed with nanoparticles (e.g., SiO2 and ZrO2). The distribution of dispersed nanoparticles can be manipulated holographically by light. This technique, the so-called holographic assembly of nanoparticles in polymer, enables us to perform the single step formation of large area photonic lattice structures for photonic applications such as holographic data storage, holographic diffractive elements and nonlinear optics. Furthermore, we showed that holographic NPC gratings could control slow-neutron (cold and very cold neutron) beams for neutron interferometer. Here we demonstrate for the first time the use of nanodiamonds (NDs), an intriguing allotrope of carbon, in NPCs to construct holographic NPC gratings with very large refractive index modulation amplitudes (Δn) and thus to efficiently control light and slow-neutron beams. This is possible because NDs have very high bulk refractive index at optical wavelengths and very large coherent and very small incoherent scattering cross sections with low absorption at slow-neutron wavelengths.
关键词： holographic grating,photopolymer,diffraction,slow-neutron,nanodiamond
更新于2025-09-12 10:27:22