• Journal of information and communication convergence engineering
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• v.17 no.1
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• pp.49-59
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• 2019

Biosensors, which are analysis devices used to convert biological reactions into electric signals, are made up of a receptor component and a signal transduction part. Graphene quantum dots (GQDs) and carbon quantum dots (CQDs) are new types of carbon nanoparticles that have drawn a significant amount of attention in nanoparticle research. The unique features exhibited by GQDs and CQDs are their excellent fluorescence, biocompatibility, and low cytotoxicity. As a result of these features, carbon nanomaterials have been extensively studied in bioengineering, including biosensing and bioimaging. It is extremely important to find biomaterials that participate in biological processes. Biomaterials have been studied in the development of fluorescence-based detection methods. This review provides an overview of recent advances and new trends in the area of biosensors based on GQDs and CQDs as biosensor platforms for the detection of biomaterials using fluorescence. The sensing methods are classified based on the types of biomaterials, including nucleic acids, vitamins, amino acids, and glucose.

• Toxicological Research
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• v.29 no.2
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• pp.121-127
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• 2013

Nanotoxicological research has shown toxicity of nanomaterials to be inversely related to particle size. However, the contribution of agglomeration to the toxicity of nanomaterials has not been sufficiently studied, although it is known that agglomeration is associated with increased nanomaterial size. In this study, we prepared aerosols of nano-sized carbon black by 2 different ways to verify the effects of agglomeration on the toxicity and deposition of nano-sized carbon black. The 2 methods of preparation included the carbon black dispersion method that facilitated clustering without sonication and the carbon black dispersion method involving sonication to achieve scattering and deagglomeration. Male Sprague-Dawley rats were exposed to carbon black aerosols 6 hr a day for 3 days or for 2 weeks. The median mass aerodynamic diameter of carbon black aerosols averaged $2.08{\mu}m$ (for aerosol prepared without sonication; group N) and $1.79{\mu}m$ (for aerosol prepared without sonication; group S). The average concentration of carbon black during the exposure period for group N and group S was $13.08{\pm}3.18mg/m^3$ and $13.67{\pm}3.54mg/m^3$, respectively, in the 3-day experiment. The average concentration during the 2-week experiment was $9.83{\pm}3.42mg/m^3$ and $9.08{\pm}4.49mg/m^3$ for group N and group S, respectively. The amount of carbon black deposition in the lungs was significantly higher in group S than in group N in both 3-day and 2-week experiments. The number of total cells, macrophages and polymorphonuclear leukocytes in the bronchoalveolar lavage (BAL) fluid, and the number of total white blood cells and neutrophils in the blood in the 2-week experiment were significantly higher in group S than in normal control. However, differences were not found in the inflammatory cytokine levels (IL-$1{\beta}$, TNF-${\alpha}$, IL-6, etc.) and protein indicators of cell damage (albumin and lactate dehydrogenase) in the BAL fluid of both group N and group S as compared to the normal control. In conclusion, carbon black aerosol generated by sonication possesses smaller nanoparticles that are deposited to a greater extent in the lungs than is aerosol formulated without sonication. Additionally, rats were narrowly more affected when exposed to carbon black aerosol generated by sonication as compared to that produced without sonication.

• Journal of Powder Materials
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• v.16 no.1
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• pp.56-62
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• 2009

The degree of WC decomposition and hardness of thermally sprayed WC-Co coatings are important factors determining the wear resistance of the coatings. In order to minimize the degree of decomposition and to increase hardness, the effects of processing parameters of high velocity oxyfuel(HVOF) spraying on various characteristics of nanostructured WC-12Co coating have been evaluated by an experimental design method. The HVOF sprayed WC-12Co coatings consisted of various carbide phases including WC, $W_2C$ and $W_3Co_3C$, with a much reduced carbon content. The degree of WC decomposition and decarburization was affected by changing barrel length and spray distance. The hardness of WC-Co coatings was strongly related to droplet temperature at substrate, and increased with increasing fuel addition and/or decreasing spray distance. The effective control of processing parameters was discussed in detail for manufacturing a high performance WC-Co coating.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3790-3794
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• 2013

Molecular dynamics simulations were performed to study the structure and stability of a nanoscale self-assembled monolayer (SAM) of alkanethiol on a gold (111) surface. The tilt angle and orientational order of the alkyl chains in the SAM island were examined by systematically varying the size of the island. The chain length dependence of the SAM island was examined by considering alkanethiols containing 12, 16, 20, and 24 carbon atoms. The minimum diameter of SAM islands made from 1-tetracosanethiol, 1-ecosanethiol, 1-hexadecanethiol and 1-dodecanethiol were 2.29, 1.9, 4.7 and 4.76 nm, respectively. These set the ultimate resolution that can be patterned by soft nanolithography. As the length of alkanethiol increases, the SAM islands became more ordered in both orientation and conformation of the alkyl chains.

• Advances in nano research
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• v.6 no.4
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• pp.357-375
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• 2018

Two dimensional (2D) atomic layered nanomaterials exhibit some of the most striking phenomena in modern materials research and hold promise for a wide range of applications including energy and biomedical technologies. Graphene has received much attention for having extremely high surface area to mass ratio and excellent electric conductivity. Graphene has also been shown to maximize the activity of surface-assembled metal nanoparticle catalysts due to its unique characteristics of enhancing mass transport of reactants to catalysts. This paper specifically investigates the strategy of pre-formed nanoparticle self-assembly used for the formation of various metal nanoparticles supported on graphene families such as graphene, graphene oxide, and reduced graphene oxide and aims at understanding the interactions between ligand-capped metal nanoparticles and 2D nanomaterials. By varying the functional groups on the ligands between alkyl, aromatic, amine, and alcohol groups, different interactions such as van der Waals, ${\pi}-{\pi}$ stacking, dipole-dipole, and hydrogen bonding are formed as the 2D hybrids produced.

• Advances in nano research
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• v.14 no.3
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• pp.235-246
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• 2023

Nanotechnology, like any other revolutionary innovation in materials science, has significantly influenced the level of competition in sports. Nanotechnology provides various benefits and enormous potential to enhance athletic equipment, making players safer, more comfortable, and more agile. Various sporting equipment is being infused with nanomaterials, including carbon nanotubes (CNTs), silica nanoparticles (SNPs), nanoclays fullerenes, etc., to enhance athlete and equipment performance. Each of these nanomaterials gives athletic equipment an extra benefit like high strength and stiffness, longevity, decreased weight, abrasion resistance, etc. This paper mechanically analysis the structural strength of tennis equipment to avoid injury. As a result, the bending forces are applied to the reinforced structures to investigate their durability.

• Clean Technology
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• v.17 no.3
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• pp.273-279
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• 2011

The physicochemical properties of manufactured nanomaterials can vary depending upon the methods of manufacture, although the utilized raw materials are same. Hence, the toxicity can also vary based on the methods of nanomaterials manufacture. In this study, we compared the toxicity effect of two types of CNTs (MWCNT, multi-walled carbon nanotube; SWCNT, single-walled carbon nanotube) that differ in length and wall number. In case of MWCNTs, inflammatory responses were more strongly induced in longer groups, whereas body weights more clearly decreased in shorter groups. SWCNT significantly decreased the relative weights of brain and kidney, and the inflow of immune cells and the hematological changes were observed significantly on day 1 and day 7 after exposure, respectively. Our results showed that the length and wall number of CNTs can serve as critical factors in the exhibited inflammation and toxicity.

• Carbon letters
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• v.14 no.2
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• pp.63-75
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• 2013

Graphene, a carbon crystal sheet of molecular thickness, shows diverse and exceptional properties ranging from electrical and thermal conductivities, to optical and mechanical qualities. Thus, its potential applications include not only physicochemical materials but also extends to biological uses. Here, we review recent experimental studies about graphene for such bioapplications. As a prerequisite to the search to determine the potential of graphene for bioapplications, the essential qualities of graphene that support biocompatibility, were briefly summarized. Then, direct examples of tissue regeneration and tissue engineering utilizing graphenes, were discussed, including uses for cell scaffolds, cell modulating interfaces, drug delivery, and neural interfaces.

• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.186-190
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• 2011

Periodically ordered mesoporous manganese oxides were synthesized in a single and double replication procedure. Mesoporous SBA-15 and -16 silica and their reverse replica carbons were successively used as hard templates. The silica and carbon pore systems were infiltrated with $Mn(NO_3)_2{\cdot}xH_2O$ or $Mn(AcAc)_2$, which was then converted to $Mn_2O_3$ at 873 K; the silica and carbon matrix were finally removed by NaOH solution or calcinations in air. The structure of the mesoporous $Mn_2O_3$, using a carbon template, corresponds to that of the original SBA-15 and SBA-16 silica. The products consist of hexagonally arranged cylindrical mesopores with crystalline pore walls or cubic mesoporous pores. The structure of replica has been confirmed by XRD, TEM analysis, and its electrochemical properties were tested with cyclic voltammetry. Formation of $Mn_2O_3$ inside the mesoporous carbon pore system showed much improved electrical properties.

• Ceramist
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• v.22 no.3
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• pp.316-327
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• 2019

Carbon nitride has drawn broad interdisciplinary attention in diverse fields such as catalyst, energy storage, gas adsorption, biomedical sensing and even imaging. Intensive studies on carbon dioxide (CO₂) capture using carbon nitride materials with various nanostructures have been reported since it is needed to actively remove CO₂ from the atmosphere against climate change. This is mainly due to its tunable structural features, excellent physicochemical properties, and basic surface functionalities based on the presence of a large number of -NH or -NH₂ groups so that the nanostructured carbon nitrides are considered as suitable materials for CO₂ capture for future utilization as well. In this review, we summarize and highlight the recent progress in synthesis strategies of carbon nitride nanomaterials. Their superior CO₂ adsorption capabilities are also discussed with the structural and textural features. An outlook on possible further advances in carbon nitride is also included.