Using detonation nanodiamond for the specific capture of glycoproteins

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 approximately 350 mg of glycoprotein/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 nonspecific binding with nonglycated 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.     

Facile synthesis of cationic polymer functionalized nanodiamond with high dispersity and antibacterial activity

In this work, a cationic polymer, N-alkylated poly (4-vinylpyridine) was applied for the surface functionalization of nanodiamond (ND). The facile route not only settled the problems of agglomeration and poor dispersion stability of ND but also rendered the nanomaterial antibacterial property. Chemical modification of the particles was confirmed by FT-IR spectroscopy and ¹HNMR, and the cationic polymer contents were determined by TGA studies. The particle diameters and dispersity of functionalized NDs were investigated by TEM and DLS measurements. It was found that extremely tight core aggregates (100–200 nm) were broken into tiny nanoparticles (20–30 nm) through functionalization with NPVP-propyl or NPVP-hexyl, which gave stable and homogeneous functionalized ND particles in colloidal solution. The antibacterial tests against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli) showed that the cationic polymer-modified ND exerted certain antibacterial activity. The FE-SEM images indicated that NPVP-hexyl-ND particles were attached to the cell wall surface of E. coli, which subsequently led to the formation of nanoscale holes on cell membrane and eventually the serious destruction of cell wall. We suspected that the interaction of NPVP-hexyl-ND with bacteria may come from the electrostatic interactions, the intermolecular and surface forces between functionalized nanoparticles and cell membranes, which may damage the outer membranes of bacteria and result in cell death.     

Study on protein conformation and adsorption behaviors in nanodiamond particle-protein complexes

In the present research, the conformation of bovine serum albumin (BSA) in the nanodiamond particle (ND)-BSA complex was studied by Fourier transform infrared spectroscopy, fluorescence spectroscopy, UV-vis spectroscopy, and circular dichroism spectroscopy. The spectroscopic study revealed that most BSA structural features could be preserved in the complex though the BSA underwent conformational changes in the complex due to ND-BSA interaction. In addition, BSA adsorption isotherms and zeta-potential measurements were employed to investigate the pH dependence of the ND-BSA interaction. The changes in surface charge of the ND-BSA complex with pH variations indicated that the binding of BSA to ND might lead to not only the adsorption of BSA onto the ND surface but also the partial breakup of ND aggregates into relatively small ND-BSA aggregates because of the strong binding force between ND and BSA. The results show that ND is an excellent platform for protein immobilization with high affinity and holds great potential to be used for biosensor applications.     

GOX-functionalized nanodiamond films for electrochemical biosensor

The importance of nanodiamond in biological and technological applications has been recognized recently, and applied in drug delivery, biochip, sensors and biosensors. Under this investigation, nanodiamond (ND) and nitrogen doped nanodiamond (NND) were deposited on n-type silicon films, and later functionalized with enzyme Glucose oxidase (GOX). The GOX functionalized doped and undoped ND films were characterized using combination of several techniques; i.e. FTIR spectroscopy, Raman spectroscopy, atomic force microscopy (AFM) and electrochemical techniques. ND/GOX and NND/GOX thin films on n-type silicon have been found to provide sensitive glucose sensor. GOX has been chosen as a model enzyme system to functionalize with ND at molecular level to understand the glucose biosensor.     

Deaggregation of nanodiamond powders using salt- and sugar-assisted milling

Diamond particles of 5-10 nm in size can be produced in large quantities by denonating oxygen-lean explosives in a closed chamber. They have numerous useful properties and are used in applications ranging from lubricants to drug delivery. Aggregation of diamond nanoparticles is limiting wider use of this important carbon nanomaterial because most applications require single separated particles. We demonstrate that dry media assisted attrition milling is a simple, inexpensive, and efficient alternative to the current ways of deaggregating of nanodiamond. This technique uses water-soluble nontoxic and noncontaminating crystalline compounds, such as sodium chloride or sucrose. When milling is complete, the media can be easily removed from the product by water rinsing, which provides an advantage when compared to milling with ceramic microbeads. Using the dry media assisted milling with subsequent pH adjustment, it is possible to produce stable aqueous nanodiamond colloidal solutions with particles <10 nm in diameter, which corresponds to 1-2 primary nanodiamond particles. The study of milling kinetics and the characterization of the produced nanodiamond colloids led us to conclude that aggregates of less than 200 nm in diameter, observed at the tail of the pore size distribution of milled nanodiamond, are loosely bonded and rather dynamic in nature. Color change observed in ND colloids upon shifting their pH toward the basic end allowed us to demonstrate that the coloration comes from the light interaction with colloidal particles and not from an increase in nondiamond carbon content.     

Study of 90Y Sorption with Nanodiamonds as Potential Carriers in the Radiopharmaceutical Composition

Radiochemistry - The sorption of 90Y with nanodiamond (ND) and oxidized nanodiamond (oxND) was studied for their subsequent application as part of radiopharmaceuticals for β-therapy in nuclear...     

Study on the Modification of Nanodiamond with DN-IO

Fourier transform infrared spectroscopy （FT-IR） and ζ-potential were introduced to study the effect of different modification parameters on the surface properties of nanodiamond （ND）. Results showed that under stirring grinding grinding conditions, ND hard aggregates were smashed and some active spots on them reacted with surfactant molecules, which led to the increase in its ζ-potential and stability. Different models of surface modification were also given in this study.     

Nanodiamond as the pH‐Responsive Vehicle for an Anticancer Drug

Cis‐dichlorodiammineplatinum(II) (CDDP, cisplatin), a widely used anticancer drug, is successfully loaded onto nanodiamond (ND) by adsorption and complexation. The CDDP–ND composite is characterized by IR spectroscopy, atomic absorption spectroscopy, thermogravimetric analysis, energy‐dispersive X‐ray spectroscopy, and X‐ray photoelectron spectroscopy. CDDP is released from the composite in phosphate‐buffered saline (PBS) of pH 6.0 at a rate higher than in PBS of pH 7.4. Therefore, it is predicted that the ND vehicle would deliver low concentrations of CDDP in the blood, but release much more drug after integration into the acidic cytoplasm, thereby reducing toxic side effects. The complexation between CDDP and the carboxyl groups on the ND surface is responsible for the pH‐responsive release property. The drug released from the composite retains the same cytotoxicity as free CDDP against human cervical cancer cells.     

Improved interaction of osteoblast-like cells with apatite–nanodiamond coatings depends on fibronectin

New apatite (AP)/nanodiamond (ND) coating has been developed to improve physical and biological properties of stainless steel (SS) versus single AP coating. Homogeneously electrodeposited AP–ND layer demonstrates increased mechanical strength, interlayer cohesion and ductility. In the absence of serum, osteoblast-like MG63 cells attach well but poorly spread on both AP and AP–ND substrata. Pre-adsorption with serum or fibronectin (FN) improves the cellular interaction—an effect that is better pronounced on the AP–ND coating. In single protein adsorption study fluorescein isothiocyanate-labeled FN (FITC-FN) shows enhanced deposition on the AP–ND layer consistent with the significantly improved cell adhesion, spreading and focal adhesions formation (in comparison to SS and AP), particularly at low FN adsorption concentrations (1 μg/ml). Higher FN concentrations (20 μg/ml) abolish this difference suggesting that the promoted cellular interaction of serum (where FN is low) is caused by the greater affinity for FN. Moreover, it is found that MG63 cells tend to rearrange both adsorbed and secreted FN on the AP–ND layer suggesting facilitated FN matrix formation.     

Mechanochemical Dispersion of Nanodiamond Aggregates in Aqueous Media

A technology of mechanochemical treatment (MCT) is introduced to modify nanodiamond (ND) surface aiming to obtaining a stable suspension with well-dispersed ND particles in aqueous medium. ND investigated in this paper is a purified product of nanometer-sized diamond synthesized by explosive detonation. As obvious aggregation and sediment were observed when the sample was added into deionized water, it is crucial to conduct deaggregation and dispersion investigations. Amid a series of mechanical treatments, i.e. grinding, stirring, ultrasonic and classification, some reagents are introduced to modify the newly created surface during aggregates comminution. For the co-effects of mechanical forces and surfactants, the mean size of particles was reduced and a stable system containing ND with narrow size distribution was prepared. Mechanism of surface reaction and modification are discussed, while AFM, Zetasizer3000HS, XRD, XPS and FTIR are utilized for the analysis. The functional chemical structure of ND p     

Effect of proton irradiation on photoluminescent properties of PDMS-nanodiamond composites

Pure poly(dimethylsiloxane) (PDMS) films, PDMS-nanodiamond (ND) and pure nanodiamond powder were irradiated with 2?MeV protons under a variety of fluence and current conditions. Upon proton irradiation, these samples acquire a fluence-dependent photoluminescence (PL). The emission and excitation spectra, photostability and emission lifetime of the induced photoluminescence of PDMS and PDMS-ND samples are reported. Pure PDMS exhibits a noticeable stable blue PL, while the PDMS-ND composites exhibit a pronounced stable green PL under 425?nm excitation. The PL of PDMS-ND composites is much more prominent than that of pure PDMS or pure ND powder even when irradiated at higher doses. The origin of the significantly enhanced PL intensity for the proton-irradiated PDMS-ND composite is explained by the combination of enhanced intrinsic PL within ND particles due to ion-implantation-generated defects and by PL originating from structural transformations produced by protons at the nanodiamond/matrix interface.     

1,3-丙二胺一纳米金刚石衍生物的合成与分散性研究

分散性差是严重制约纳米金刚石应用的重要原因.采用1,3-丙二胺修饰纳米金刚石(ND),合成出结构新颖的1,3-丙二胺-纳米金刚石衍生物(ND-NH2).FTIR分析表明,1,3-丙二胺分子通过酰胺键与ND共价键接.ND-NH2中ND的含量约为29.97%(质量分数),并可溶于无机或有机酸水溶液,以及丙酮、CH2Cl2、NMP、DMF、DMAc、DMSO等有机溶剂.激光粒度和TEM分析表明,经1,3-丙二胺改性后,纳米金刚石的分散性显著改善,其平均粒径从3.301μm降低至0.166μm,为在复合电镀和润滑领域的进一步研究与应用提供了良好基础.     

Cellular and in vitro toxicity of nanodiamond-polyaniline composites in mammalian and bacterial cell

The composite nanodiamond (ND) particles are rapidly emerging as promising material for the next generation agent for drug delivery, biosensors, or imaging contrast applications. Consequently, the health risks associated with the exposure to nanocomposite materials are utmost important. The objective of our work is to study the toxic effects of the nanodiamond-polyaniline (ND-Pani) composites in Human Embryonic Kidney (HEK) cell line. Toxic effects of either ND or ND-Pani nanocomposite in powder form on HEK293 are tested using MTT assay. Results indicated that there was no significant difference in the cell survival between samples treated with ND-Pani nanocomposite and the control sample for the two lower concentrations used in the experiments (p < 0.05). Morphology of the cells was not significantly affected due to the inclusion of nanocomposites during the incubation phase. The stability of the film was also improved due to the inclusion of the nanodiamond particles into the polymeric matrix making it suitable for electrochemical sensing applications. Experimental results have shown that the toxicity effect of lower concentration of ND-Pani composite is negligible, thus indicating that below 1 μg/ml could be a safer range without secondary toxicity effect.     

The effect of diamond nanoparticles on redox and immune parameters in rats

The objective of the study was to evaluate the effect of nanodiamond (ND) particles manufactured by detonation method (size of grains 2-10 nm) on organism health status. Wistar rats were administrated with diamond nanoparticles colloid by intravenous and intraperitoneal injection. Both routes of administration increased superoxide dismutase (SOD) activity and at the same time decreased activity of glutathione reductase (GR) and glutathione peroxidase (GPx) within erythrocytes. ND did not significantly affect neither total antioxidative state (TAS) nor thiobarbituric acid reactive substances (TBARS) in examined animals blood plasma. This study was also designed to examine the effect of ND on the phagocytosis activity and oxidative burst of innate immune cells. Both intravenous and intraperitoneal administration of ND hydrocolloid decreased the number of the phagocytosing neutrophiles stimulated by E. coli. Independently of the injection method nanodiamond increased the number of cells with stimulated oxidative burst and it suppressed the mechanism of oxygen dependent bacteria elimination.     

Study on the Modification of Nanodiamond with DN-10

Fourier transform infrared spectroscopy (FT-IR) and ζ-potential were introduced to study the effect of different modification parameters on the surface properties of nanodiamond (NO). Results showed that under stirring grinding conditions, ND hard aggregates were smashed and some active spots on them reacted with surfactant molecules, which led to the increase in its ζ-potential and stability. Different models of surface modification were also given in this study.     

Promising commercial reinforcement to the nanodiamond/epoxy composite by grafting ammonium ions

A simple, economic, efficient and eco-friendly nanodiamond (ND) modifying method to reinforce the ND/epoxy composite for the industrialization of the high-performance ND/epoxy composite is always desired. In the present work, the ND was successfully modified only using aqueous ammonia through an easy-to-operate method by replacing the hydrogen atoms in the carboxyl group with ammonium ions. Ammonia, which is the only pollutant in the process, could be recycled. The modified ND/epoxy composite showed an overwhelming advantage over the neat epoxy or the ND/epoxy composite in storage modulus in their glassy state without any degradation of tensile strength, hardness and fracture toughness.     

Preparation and characterization of cross-linked phospholipid bilayer capillary coatings for protein separations

Analysis of protein and peptide mixtures via capillary electrophoresis is hindered by nonspecific adsorption of analytes to the capillary walls, resulting in poor separations and quantitative reproducibility. Phospholipid bilayer (PLB) coatings are very promising for improving protein and peptide separations due to the native resistance to nonspecific protein adsorption offered by PLBs; however, these coatings display limited chemical and temporal stability. Here, we show the preparation and characterization of a highly cross-linked, polymerized phospholipid capillary coating prepared using bis-SorbPC. Poly(bis-SorbPC) PLB coatings are prepared in situ within fully enclosed fused silica capillaries via self-assembly and radical polymerization. Polymerization of the PLB coating stabilizes the membrane against desorption from the surface and migration in an electric field, improves the temporal and chemical stability, and allows for the separation of both cationic and anionic proteins, while preserving the native resistance to nonspecific protein adsorption of natural PLBs.     

Stable and functional immobilization of histidine-tagged proteins via multivalent chelator headgroups on a molecular poly(ethylene glycol) brush

We present a generic approach for immobilizing oligohistidine-tagged proteins with high stability and homogeneous functionality onto glass-type surfaces. Multivalent chelator heads (MCH) carrying two and three nitrilotriacetic acid (NTA) moieties were coupled with controlled surface concentration to glass surfaces premodified with an ultrathin two-dimensional polymer brush of a bifunctional poly(ethylene glycol). Low roughness and lateral homogeneity of these surfaces were confirmed by AFM and fluorescence microscopy, respectively. Protein immobilization and interactions at these interfaces were studied by label-free and fluorescence detection. Oligohistidine-tagged proteins bound specifically to NTA loaded with nickel(II) ions and could be eluted with imidazole. More than 90% of the immobilized protein preserved its activity. In contrast to mono-NTA, immobilized multivalent chelator heads bound oligohistidine-tagged proteins stoichiometrically and with high stability, even at very low chelator surface concentrations. Thus, an excess of the metal chelator sites was not necessary, and excessive binding sites could be quantitatively blocked with an indifferent protein. As a consequence, increased functional stability of the immobilized protein and a substantial reduction in nonspecific adsorption were achieved. Binding of histidine-tagged proteins to the MCH-modified surface was efficiently blocked by stoichiometric amounts of soluble MCH, and biomolecular interaction unbiased by the interaction of the histidine tag to the surface-bound MCH was observed. These excellent features and the compatibility with many solid-phase analytical techniques make this surface chemistry beneficial for functional protein analysis.     

Nonlinear scattering of light in nanodiamond hydrosol

The nonlinear scattering of light under the conditions of optical limiting of nanosecond pulsed laser radiation at a wavelength of 1064 nm in a nanodiamond (ND) hydrosol has been experimentally studied. Superstable hydrosols were obtained from detonation NDs with a modified surface. Using an improved scheme of z scanning, it is shown that a decrease in the optical transmission coefficient of an ND hydrosol under optical limiting conditions is due to enhanced nonlinear scattering. It is established that the energy of pulsed radiation scattered at a right angle obeys a power law in dependence on the energy density of incident radiation pulses. Hydrosols of detonation NDs with the modified surface exhibit high stability with respect to the periodic laser action at high power density.     

Single-monomer formulation of polymerized polyethylene glycol diacrylate as a nonadsorptive material for microfluidics

Nonspecific adsorption in microfluidic systems can deplete target molecules in solution and prevent analytes, especially those at low concentrations, from reaching the detector. Polydimethylsiloxane (PDMS) is a widely used material for microfluidics, but it is prone to nonspecific adsorption, necessitating complex chemical modification processes to address this issue. An alternative material to PDMS that does not require subsequent chemical modification is presented here. Poly(ethylene glycol) diacrylate (PEGDA) mixed with photoinitiator forms on exposure to ultraviolet (UV) radiation a polymer with inherent resistance to nonspecific adsorption. Optimization of the polymerized PEGDA (poly-PEGDA) formula imbues this material with some of the same properties, including optical clarity, water stability, and low background fluorescence, that make PDMS so popular. Poly-PEGDA demonstrates less nonspecific adsorption than PDMS over a range of concentrations of flowing fluorescently tagged bovine serum albumin solutions, and poly-PEGDA has greater resistance to permeation by small hydrophobic molecules than PDMS. Poly-PEGDA also exhibits long-term (hour scale) resistance to nonspecific adsorption compared to PDMS when exposed to a low (1 μg/mL) concentration of a model adsorptive protein. Electrophoretic separations of amino acids and proteins resulted in symmetrical peaks and theoretical plate counts as high as 4 × 10(5)/m. Poly-PEGDA, which displays resistance to nonspecific adsorption, could have broad use in small volume analysis and biomedical research.