Multi-walled Carbon nanotube, its role and implications in biological systems are currently under... more Multi-walled Carbon nanotube, its role and implications in biological systems are currently under evaluation and became interesting for many researchers primarily working on the interface of chemistry, physics and biology. However, concerns about the potential toxicity of multi-walled carbon nanotubes have been raised. To carry such affords, herein we investigate the effects of carboxylic acid functionalized water soluble carbon nanotube (wsCNT) on the growth of gram Cicer arietinum plant. The growth of gram plants was observed with and without the presence of wsCNT to demonstrate that carboxylated functionalized multi-walled carbon nanotubes showed better growth and under more wsCNT, the growth was enhanced without showing apparent toxicity. Although this is a preliminary study with a small group of plants, our results encourage further confirmation studies with larger groups of plants.
Water soluble photoluminescent carbon nano-onions were synthesized from vegetable ghee using trad... more Water soluble photoluminescent carbon nano-onions were synthesized from vegetable ghee using traditional pyrolytic approach for imaging cells and selective-immediate detection of glucose via fluorescent “turn-off”/“turn-on” technique.
ABSTRACT Carbon nano-onions, as a newly-emergent member of the carbon family, have attracted atte... more ABSTRACT Carbon nano-onions, as a newly-emergent member of the carbon family, have attracted attention in its both dry and wet applications. Here we report in vivo effects of water-soluble carbon nano-onions (wsCNOs) introduced in common food web of two model organisms: unicellular Escherichia coli (E. coli) and multicellular Caenorhabditis elegans (C. elegans). At first, CNOs are fed to E. coli and, subsequently, the E. coli are fed to C. elegans. It is found that wsCNOs serve as highly-fluorescent bioimaging agent. The results do not reflect any toxic effect of wsCNOs on the growth of these organisms suggesting new avenues in nanotoxicology research and biomedical application including drug delivery
Water soluble carbon nanotubes (wsCNTs) with network structure possessing multipodal junctions we... more Water soluble carbon nanotubes (wsCNTs) with network structure possessing multipodal junctions were isolated by the oxidative treatment of carbon soot (generally discarded as waste during fullerene synthesis) using dilute nitric acid as black crystalline solid. wsCNTs having multipodal junctions are highly soluble in water due to the incorporation of adequate amount of hydrophilic carboxylic acid groups. Microscopic investigation shows the presence of extensive networked wsCNTs possessing different types of junctions such as tri (“Y”, “T”), tetrapodal, pentapodal and even “H” type junctions. Furthermore these wsCNTs possessing interesting magnetic properties due to presence of multipodal junctions and defective surfacial structures, usually known as surfacial ‘defects’ on graphitic pool (sp2 hybridized carbon atoms) of nanotubes. Easy solubility along with magnetic properties makes these wsCNTs to be used as a potential probe for their use in biological and spintronic applications respectively.
ABSTRACT We report here the synthesis and structural characterization of a new discrete bis-dithi... more ABSTRACT We report here the synthesis and structural characterization of a new discrete bis-dithiolene complex, [PPh 4 ][Cu(DMED) 2 ] (1; DMED = 1,2-dicarbomethoxy-1,2-dithiolate), involving the reaction between a copper polysulfide precursor with activated acetylene. 1 is stable, showing a sulfur-based radical character, as observed by electronic, EPR and cyclic voltammetric studies. This complex, possessing terminal –COOCH 3 groups, forms nanospheres by hydrogen bonding in a mixture of solvents containing water as one of the components. These nanospheres further aggregate with water soluble (carboxy-lated) carbon nanotubes (wsCNTs). These nano-composites are assisted by hydrogen bonding between the carboxylic acid groups of the wsCNTs and the peripheral –COOCH 3 groups of the coordinated dithiolenes of the nanospheres, which is promoted by water molecules. Interaction between the nano-spheres on wrapping with wsCNTs, in forming the nano-composites, showed a perturbed EPR signal of the sulfur radical originating from the oxidised dithiolate ligand of the discrete complex 1.
Water soluble carbon nanotubes (wsCNTs) show enhancement of the growth rate of common gram (Cicer... more Water soluble carbon nanotubes (wsCNTs) show enhancement of the growth rate of common gram (Cicer arietinum) plants. Treating plants with up to 6.0 μg mL(-1) of wsCNT shows an increased growth rate in every part of the plant including the roots, shoots and also in branching. The noticeable difference between the wsCNT treated and controlled gram is the water uptake; in the former it is dramatically enhanced, suggesting better water absorption and retention related to enhanced growth. This work shows that unlike CNTs, wsCNTs are non-toxic to plant cells that conserve water transport in plants.
Water-soluble carbon nano-onions (wsCNOs) isolated from wood wool-a wood-based pyrolysis waste pr... more Water-soluble carbon nano-onions (wsCNOs) isolated from wood wool-a wood-based pyrolysis waste product of wood, can enhance the overall growth rate of gram (Cicer arietinum) plants. Treatment of plants with upto 30 μg mL(-1) of wsCNOs for an initial 10 day period in laboratory conditions led to an increase in the overall growth of the plant biomass. In order to examine the growth stimulating effects of wsCNOs under natural conditions, 10 day-old plants treated with and without wsCNOs were transplanted into soil of standard carbon and nitrogen composition. We observed an enhanced growth rate of the wsCNOs pre-treated plants in soil, which finally led to an increased productivity of plants in terms of a larger number of grams. On analyzing the carbon, hydrogen, and nitrogen (CHN) content for the shoot and fruit sections of the plants treated with and without wsCNOs, only a minor difference in the composition was noticed. However, a slight increase in the percentage of carbon and hydrogen in shoots reflects the synthesis of more organic biomass in the case of treated plants. This work shows that wsCNOs are non-toxic to plant cells and can act as efficient growth stimulants which can be used as benign growth promoters.
Carbon nanocubes and nanobricks were synthesized by pyrolyzing rice powder at 600 degrees C under... more Carbon nanocubes and nanobricks were synthesized by pyrolyzing rice powder at 600 degrees C under nitrogen atmosphere. Purification with concentrated nitric acid introduced approximately 0.1 mol/g of carboxylic acid groups as found by acid-base titrimetric analysis. XRD pattern showed the 0.15 mol/g basic graphitic structure of these nano carbon materials. Their SEM and TEM images revealed cube or brick shaped nano crystals. These nanocrystals are further characterized by FT-IR, Raman, and EDAX analysis. High density wrapping of carboxylated acid groups introduces surface passivation of these nano carbon cubes and nano carbon bricks exhibiting photoluminescence. Solid state electronic spectrum showed several bands in the ultraviolet and visible region and excitation at 336 and 474 nm generates photoluminescence respectively in the ultraviolet and visible region.
ABSTRACT A low cost synthesis of multicolor fluorescent carbon dots (C-dots) from edible sugars i... more ABSTRACT A low cost synthesis of multicolor fluorescent carbon dots (C-dots) from edible sugars is described here. Common sugars like dextrose, lactose or maltose in aqueous medium gets dehydrated using phosphorus pentoxide (P2O5). The reaction is facile and completed within few minutes to form insoluble carbon (C-dots) mostly having the graphitic (G-band, Raman) sp2 hybridized carbon atoms (C-atoms). This insoluble carbon on oxidative treatment with nitric acid produced disordered sp3 (D-band retaining G-band, Raman) hybridized C-atoms, originated from the graphitic pool with sp2 hybridized C-atoms. This high density assimilation of self passivated "surfacial defects" become emissive during electronic transitions. Surfacial defects due to high degree of electrophilic carboxylation create the water soluble version of multicolor fluorescent C-dots as "water soluble fluorescent carbon dots" (wsFCDs). wsFCDs being itself self-passivated imposes the tunable multicolor emission throughout the visible spectrum without having any external coating and surface passivation and could be used as multicolor fluorescent probe especially in the emerging field of optical bio-imaging.
Black carbon (BC) (as partly burnt black particulate matter) present indoor are deposited on inte... more Black carbon (BC) (as partly burnt black particulate matter) present indoor are deposited on interior surfaces of the indoors (easily visualize over the blades of electric fan/exhausts and over domestic spider webs) are known to be a potential indoor pollution problem. We detect with the help of indoor spider webs the floating BC contains a significant amount of defective multiwalled carbon nanotubes (MWCNTs) possessing room temperature ferromagnetism. Microscopic studies shows a lot of internal and surfacial defects in these indoor-MWCNTs. Electron paramagnetic resonance (EPR) showed the presence of very stable carbon centred radicals in these indoor-MWCNTs. Room temperature ferromagnetism most importantly originated by the presence of a large amount of unpaired spin frustrated carbon centred radicals (trapped in defects, junctions and fractures) which are inadvertently formed during the pyrolysis of carbonaceous materials through routine domestic activities.
Abstract: The nanocrystal structure of a hetero-polyatomic metal-ligand complex,[PPh 4][Ni II (L ... more Abstract: The nanocrystal structure of a hetero-polyatomic metal-ligand complex,[PPh 4][Ni II (L 2−)(L 1−·)],(1)(L= 1, 2-dicarbomethoxyethylene dithiolate) has been arrived at from its molecular structure obtained by X-ray crystallography. The complex (1) exhibits ...
Multi-walled Carbon nanotube, its role and implications in biological systems are currently under... more Multi-walled Carbon nanotube, its role and implications in biological systems are currently under evaluation and became interesting for many researchers primarily working on the interface of chemistry, physics and biology. However, concerns about the potential toxicity of multi-walled carbon nanotubes have been raised. To carry such affords, herein we investigate the effects of carboxylic acid functionalized water soluble carbon nanotube (wsCNT) on the growth of gram Cicer arietinum plant. The growth of gram plants was observed with and without the presence of wsCNT to demonstrate that carboxylated functionalized multi-walled carbon nanotubes showed better growth and under more wsCNT, the growth was enhanced without showing apparent toxicity. Although this is a preliminary study with a small group of plants, our results encourage further confirmation studies with larger groups of plants.
Water soluble photoluminescent carbon nano-onions were synthesized from vegetable ghee using trad... more Water soluble photoluminescent carbon nano-onions were synthesized from vegetable ghee using traditional pyrolytic approach for imaging cells and selective-immediate detection of glucose via fluorescent “turn-off”/“turn-on” technique.
ABSTRACT Carbon nano-onions, as a newly-emergent member of the carbon family, have attracted atte... more ABSTRACT Carbon nano-onions, as a newly-emergent member of the carbon family, have attracted attention in its both dry and wet applications. Here we report in vivo effects of water-soluble carbon nano-onions (wsCNOs) introduced in common food web of two model organisms: unicellular Escherichia coli (E. coli) and multicellular Caenorhabditis elegans (C. elegans). At first, CNOs are fed to E. coli and, subsequently, the E. coli are fed to C. elegans. It is found that wsCNOs serve as highly-fluorescent bioimaging agent. The results do not reflect any toxic effect of wsCNOs on the growth of these organisms suggesting new avenues in nanotoxicology research and biomedical application including drug delivery
Water soluble carbon nanotubes (wsCNTs) with network structure possessing multipodal junctions we... more Water soluble carbon nanotubes (wsCNTs) with network structure possessing multipodal junctions were isolated by the oxidative treatment of carbon soot (generally discarded as waste during fullerene synthesis) using dilute nitric acid as black crystalline solid. wsCNTs having multipodal junctions are highly soluble in water due to the incorporation of adequate amount of hydrophilic carboxylic acid groups. Microscopic investigation shows the presence of extensive networked wsCNTs possessing different types of junctions such as tri (“Y”, “T”), tetrapodal, pentapodal and even “H” type junctions. Furthermore these wsCNTs possessing interesting magnetic properties due to presence of multipodal junctions and defective surfacial structures, usually known as surfacial ‘defects’ on graphitic pool (sp2 hybridized carbon atoms) of nanotubes. Easy solubility along with magnetic properties makes these wsCNTs to be used as a potential probe for their use in biological and spintronic applications respectively.
ABSTRACT We report here the synthesis and structural characterization of a new discrete bis-dithi... more ABSTRACT We report here the synthesis and structural characterization of a new discrete bis-dithiolene complex, [PPh 4 ][Cu(DMED) 2 ] (1; DMED = 1,2-dicarbomethoxy-1,2-dithiolate), involving the reaction between a copper polysulfide precursor with activated acetylene. 1 is stable, showing a sulfur-based radical character, as observed by electronic, EPR and cyclic voltammetric studies. This complex, possessing terminal –COOCH 3 groups, forms nanospheres by hydrogen bonding in a mixture of solvents containing water as one of the components. These nanospheres further aggregate with water soluble (carboxy-lated) carbon nanotubes (wsCNTs). These nano-composites are assisted by hydrogen bonding between the carboxylic acid groups of the wsCNTs and the peripheral –COOCH 3 groups of the coordinated dithiolenes of the nanospheres, which is promoted by water molecules. Interaction between the nano-spheres on wrapping with wsCNTs, in forming the nano-composites, showed a perturbed EPR signal of the sulfur radical originating from the oxidised dithiolate ligand of the discrete complex 1.
Water soluble carbon nanotubes (wsCNTs) show enhancement of the growth rate of common gram (Cicer... more Water soluble carbon nanotubes (wsCNTs) show enhancement of the growth rate of common gram (Cicer arietinum) plants. Treating plants with up to 6.0 μg mL(-1) of wsCNT shows an increased growth rate in every part of the plant including the roots, shoots and also in branching. The noticeable difference between the wsCNT treated and controlled gram is the water uptake; in the former it is dramatically enhanced, suggesting better water absorption and retention related to enhanced growth. This work shows that unlike CNTs, wsCNTs are non-toxic to plant cells that conserve water transport in plants.
Water-soluble carbon nano-onions (wsCNOs) isolated from wood wool-a wood-based pyrolysis waste pr... more Water-soluble carbon nano-onions (wsCNOs) isolated from wood wool-a wood-based pyrolysis waste product of wood, can enhance the overall growth rate of gram (Cicer arietinum) plants. Treatment of plants with upto 30 μg mL(-1) of wsCNOs for an initial 10 day period in laboratory conditions led to an increase in the overall growth of the plant biomass. In order to examine the growth stimulating effects of wsCNOs under natural conditions, 10 day-old plants treated with and without wsCNOs were transplanted into soil of standard carbon and nitrogen composition. We observed an enhanced growth rate of the wsCNOs pre-treated plants in soil, which finally led to an increased productivity of plants in terms of a larger number of grams. On analyzing the carbon, hydrogen, and nitrogen (CHN) content for the shoot and fruit sections of the plants treated with and without wsCNOs, only a minor difference in the composition was noticed. However, a slight increase in the percentage of carbon and hydrogen in shoots reflects the synthesis of more organic biomass in the case of treated plants. This work shows that wsCNOs are non-toxic to plant cells and can act as efficient growth stimulants which can be used as benign growth promoters.
Carbon nanocubes and nanobricks were synthesized by pyrolyzing rice powder at 600 degrees C under... more Carbon nanocubes and nanobricks were synthesized by pyrolyzing rice powder at 600 degrees C under nitrogen atmosphere. Purification with concentrated nitric acid introduced approximately 0.1 mol/g of carboxylic acid groups as found by acid-base titrimetric analysis. XRD pattern showed the 0.15 mol/g basic graphitic structure of these nano carbon materials. Their SEM and TEM images revealed cube or brick shaped nano crystals. These nanocrystals are further characterized by FT-IR, Raman, and EDAX analysis. High density wrapping of carboxylated acid groups introduces surface passivation of these nano carbon cubes and nano carbon bricks exhibiting photoluminescence. Solid state electronic spectrum showed several bands in the ultraviolet and visible region and excitation at 336 and 474 nm generates photoluminescence respectively in the ultraviolet and visible region.
ABSTRACT A low cost synthesis of multicolor fluorescent carbon dots (C-dots) from edible sugars i... more ABSTRACT A low cost synthesis of multicolor fluorescent carbon dots (C-dots) from edible sugars is described here. Common sugars like dextrose, lactose or maltose in aqueous medium gets dehydrated using phosphorus pentoxide (P2O5). The reaction is facile and completed within few minutes to form insoluble carbon (C-dots) mostly having the graphitic (G-band, Raman) sp2 hybridized carbon atoms (C-atoms). This insoluble carbon on oxidative treatment with nitric acid produced disordered sp3 (D-band retaining G-band, Raman) hybridized C-atoms, originated from the graphitic pool with sp2 hybridized C-atoms. This high density assimilation of self passivated "surfacial defects" become emissive during electronic transitions. Surfacial defects due to high degree of electrophilic carboxylation create the water soluble version of multicolor fluorescent C-dots as "water soluble fluorescent carbon dots" (wsFCDs). wsFCDs being itself self-passivated imposes the tunable multicolor emission throughout the visible spectrum without having any external coating and surface passivation and could be used as multicolor fluorescent probe especially in the emerging field of optical bio-imaging.
Black carbon (BC) (as partly burnt black particulate matter) present indoor are deposited on inte... more Black carbon (BC) (as partly burnt black particulate matter) present indoor are deposited on interior surfaces of the indoors (easily visualize over the blades of electric fan/exhausts and over domestic spider webs) are known to be a potential indoor pollution problem. We detect with the help of indoor spider webs the floating BC contains a significant amount of defective multiwalled carbon nanotubes (MWCNTs) possessing room temperature ferromagnetism. Microscopic studies shows a lot of internal and surfacial defects in these indoor-MWCNTs. Electron paramagnetic resonance (EPR) showed the presence of very stable carbon centred radicals in these indoor-MWCNTs. Room temperature ferromagnetism most importantly originated by the presence of a large amount of unpaired spin frustrated carbon centred radicals (trapped in defects, junctions and fractures) which are inadvertently formed during the pyrolysis of carbonaceous materials through routine domestic activities.
Abstract: The nanocrystal structure of a hetero-polyatomic metal-ligand complex,[PPh 4][Ni II (L ... more Abstract: The nanocrystal structure of a hetero-polyatomic metal-ligand complex,[PPh 4][Ni II (L 2−)(L 1−·)],(1)(L= 1, 2-dicarbomethoxyethylene dithiolate) has been arrived at from its molecular structure obtained by X-ray crystallography. The complex (1) exhibits ...
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Papers by Sumit Sonkar