You need to be a member of The International NanoScience Community - Nanopaprika.eu to add comments!
Join The International NanoScience Community - Nanopaprika.eu
You need to be a member of The International NanoScience Community - Nanopaprika.eu to add comments!
Join The International NanoScience Community - Nanopaprika.eu
Replies
1.nano silicon carbide
Chemical formula: SiC beta
Purity: 97-99%
[O] <0.6-1%
free [Si] <0.2%
APS: 40-50 nm
SSA: 60-80 m2/g
True density: 3.22 g/cm3
Bulk density: 0.08 g/cm3
Crystal cell: Cubic
Color: Green
Shelf time: 24 months
2.nano silicon nitride
Chemical formula: Si3N4 amorphous
Purity: 97.5-99%
[O] <0.7-1%
free [Si] <0.4%
APS: 20 nm
SSA: 115 m2/g
True density: 3.4 g/cm3
Bulk density: 0.05 g/cm3
Crystal cell: amorphous
Color: White
Shelf time: 24 months
3.nano titanium nitride
Chemical formula: TiN
Purity: 97-99%
[O] < 1%, (C<0.2%, Fe<0.04%, Si<0.02%)
APS: 10-20 nm
SSA: 80 m2/g
True density: 5.22 g/cm3
Bulk density: 0.08 g/cm3
Crystal cell: Face Center Cubic
Color: Gray White
Shelf time: 24 months
Let me see. Thanks to Nivashni and Dr.Varima Bokare for their enlightening comments.Kindly share this discussion with all your friends to make the discussion comprehensive to get more suggestions.
Its very true that companies now a days under the name tag of nano are marketting various stuff from cosmetics to home appliances without giving the details ..........infact any product having nano should decribe the details about chemical nature and full background information. i recently read an article where few reseachers have proposed the US -EPA to declare silver nano as a pesticide....tell you what few years back when i was in pune doing my phd there was an expo for selling home appliances........many companies had come including the ones selling silver nano fridge n washing machines..........when i asked there sales people to describe me what exaclty silver nano does , none of them were able to answer me.........so you see if they themselves are unaware then ........
What is nanotechnology and nano-silver?
What is nanotechnology and nano-silver?
Nanotechnology is a rapidly growing science of producing and utilizing nano-sized particles that measure in nanometers (1 nm = 1 billionth of a metre). One nanomaterial that is having an early impact in healthcare products is nano-silver.
Silver has been used for the treatment of medical ailments for over 100 years due to its natural antibacterial and antifungal properties. The nano-silver particles typically measure 25nm. They have extremely large relative surface area, increasing their contact with bacteria or fungi, and vastly improving its bactericidal and fungicidal effectiveness.
The nano-silver when in contact with bacteria and fungus will adversely affect cellular metabolism and inhibit cell growth. The nano-silver suppresses respiration, basal metabolism of electron transfer system, and transport of substrate in the microbial cell membrane. The nano-silver inhibits multiplication and growth of those bacteria and fungi which cause infection, odour, itchiness and sores
Nano-silver can be applied to a range of other healthcare products such as dressings for burns, scald, skin donor and recipient sites; plasters for surgical and trauma wounds; aqueous gel for spots, acne and cavity wounds; and female hygiene products - panty liners, sanitary towels and pants.
Nano-silver is:
· Highly efficacious
· Fast acting
· Non Poisonous
· Non stimulating
· Non allergic
· Tolerance Free
· Hydrophilic
Nano-silver, though an effective antibacterial (She and Zhang 2003, Lok et al. 2006), may also cause genotoxic impact. Case histories indicate that dermal exposure to silver or silver compounds for extended periods can lead to generalize skin discolouration. Mild allergic responses attributed to dermal contact with silver or silver compounds was also reported (ATSDR 1990). The most commonly discussed side effects from excessive in take of elemental silver is a condition known as argyria. The excess silver usually gets deposited in the skin, organs and other tissues. The deposition of silver in the skin may lead to the change of skin colour to a gray or bluish gray (East et al. 1980). Nano-silver, is smallest enough to enter the skin pores if applied on the skin and it may result in damage to the skin cells. Research on the nano particles has revealed the ability of these particles to pass through cell walls and damage DNA (ATSDR 1990).
In humans, less than 1% of topically applied silver compounds are absorbed through the skin (Snyder et al. 1975). Nano-silver, incorporated in cosmetics or consumer products may enter the human cells easily through both intact and damaged skin. Silver particles once deposited in the layers of skin of humans, it accumulates throughout the ageing process (Hostynek et al. 1993).
Earlier reports showed that high concentrations of nano-silver based inorganic antibacterial agents have cytotoxic effects on rat's fibroblasts L-929 (Zhand et al. 2005). Histopathological studies on the effect of pure silver showed accumulation of granules in the cytoplasm and showed little cytotoxicity. It is supported by the study of Schmahl and Steinhoff (1960) that colloidal silver injected subcutaneously, into rats resulted in tumour in 8/26 rats, that survived longer than 14 months.
In proteomic studies nano-silver was shown to destabilize the outer membrane, collapse the plasma membranes' potential and deplete the levels of intracellular ATP of the bacterial cells (Lok et al. 2006). Similar studies on the effect of nano-silver on plasma membranes and ATP in mammalian and other eukaryotic systems are lacking.
In the present preliminary toxicity assay, treatments with 10, 20, 40 and 50 ppm of nano-silver produced a dose and duration-dependent MI and CA in Allium root meristems. The reduction of MI during all treatments clearly indicates the mitodepressive and cytotoxic effect of nano-silver. This might have been achieved by the inhibition of DNA synthesis at S-phase (Sudhakar et al. 2001). The high frequency of mitotic abnormalities such as C-metaphase, disturbed metaphase and disturbed anaphase induced by nano-silver primarily reflects its effects on mitotic spindles, altering the orientation of chromosomes at various stages of the cell cycle. Impairment of mitotic spindle function is probably due to the interaction of nano-silver with tubulin-SH group (Kuriyama and Sakai, 1974). Observation of chromosome stickiness was another type of abnormality induced by nano-silver. This stickiness presumably is due to intermingling of chromatin fibres, which leads to sub chromatid connections between chromosomes (McGill et al. 1974, Klasterska et al. 1976). The induction of chromosomal breaks and micronuclei by nano-silver indicates the clastogenic potential of the test chemical, which may lead to a loss of genetic material and these have been regarded as an indication of mutagenicity of the inducers (Raun et al. 1992). In conclusion, the results of present study in Allium root meristems suggest that nano-silver possesses mitodepressive, mitoclassic and clastogenic properties.
The present study provides an evidence for the possible genotoxic effect of nano-silver on plant system. Though the results in the plant system cannot be extrapolated directly to animal systems, the findings of the present study raise the need for elaborate evaluations to ensure the safety of nano-silver.