Navami Dayal - Academia.edu (original) (raw)

Papers by Navami Dayal

MGM Journal of Medical Sciences

Although in vivo studies have been modeled using higher mammal systems, the lower vertebrate zebr... more Although in vivo studies have been modeled using higher mammal systems, the lower vertebrate zebrafish (Danio rerio) has gained tremendous attention as a model system. Gold nanoparticles (GNPs) attract the interest of scientists due to their promising potential applications in medicine and targeted drug delivery. The purpose to use GNPs in vivo is that gold in bulk form is nontoxic and apply the positive potentials of nanoparticles. Bulk gold is century-long accepted as a safeto-use metal. Gold in its nanoform has distinct chemical and physical properties and the large amount of surface atoms make GNPs reactive. Moreover, GNPs can potentially access many cellular or subcellular structures, which are unreachable by the larger compound and may induce toxic effects. This paper addresses effects of spherical GNPs of average size 15 nm on reproductive organs after subacute exposure in adult male and female zebrafish. Gold nanoparticles were chemically synthesized and characterized by transmission electron microscope. The primary objective of this study was to determine if exposure to GNPs altered cellular morphology of gonads. The adult fish of both sexes were administered orally with these GNPs at a dose of 20 μg/gm. At the end of the study, quantification of gold content was estimated using two different tools: inductive coupled plasmon-atomic emission spectroscopy (ICP-AES) and inductive coupled plasmon-mass spectroscopy (ICP-MS). No gold metal accumulation was detected in treated group of male and female zebrafish at subacute exposures on estimation through ICP-AES. On analysis using ICP-MS, 0.44 ± 0.18 µg/gm organ weight was detected in ovaries and 4.6 ± 3.20 µg/gm organ weight was detected in testes of treated groups. However, the pattern of accumulation was found to be nonsignificant when compared with the control group at a p-value >0.05. Histopathological analysis of reproductive organs showed no significant changes in cellular morphology of testes and ovaries.

International Journal of Advanced Research, 2016

MGM Journal of Medical Sciences, 2014

Owing to widespread applications, synthesis and characteri zation of silver nanoparticles is rece... more Owing to widespread applications, synthesis and characteri zation of silver nanoparticles is recently attracting considerable attention. Increasing environmental concerns over chemical synthesis routes have resulted in attempts to develop biomimetic approaches. One of them is synthesis using plant parts, which eliminates the elaborate process of maintaining the microbial culture and often found to be kinetically favorable than other bioprocesses. The present study deals with investigating the effect of process microwave irradiation, interaction time on the morpho logy and size of silver nanoparticles synthesized using aqueous extract of Tulsi. Plant extract from ocimum sanctum (Tulsi) was used for the synthesis of silver nanoparticles (AgNPs) from silver nitrate solution. Silver nanoparticles were characterized by UVVis spectrophotometer and scanning electron microscope (SEM). The formation and stability of the reduced silver nanoparticles in the colloidal solution was monitored by UVVis spectrophotometer analysis. Nanoparticles ranges from 20 to 40 nm in size with nearly spherical shape were produced. SEM determination of the brown color stable samples showed the formation of silver nanoparticles and well dispersed nanoparticles could be seen in the samples treated with silver nitrate. These silver nanoparticles have proven to be stable for more than 3 months. It can be inferred from the study that fine tuning the bioprocess parameters will enhance possibilities of desired nanoproduct tail or made for particular applications.

MGM Journal of Medical Sciences, 2014

Genotoxic effects of silver nanoparticles (Ag-np) in a vertebrate model system were investigated.... more Genotoxic effects of silver nanoparticles (Ag-np) in a vertebrate model system were investigated. Effects and accumulation patterns of silver nanoparticles were studied using zebrafish embryos. Nanoparticles of silver were synthesized by chemical reduction of silver nitrate, using sodium borohydride as reducing agent and polyvinyl pyrolidene as a stabilizer. These nanoparticles were characterized by UV/ Vis spectrophotometer (absorption spectra), Transmission electron microscopy and were found to have the size range of 4 to 10 nm. Evaluation of cytotoxicity was carried out at various concentrations to obtain the LD 50 value. Dose dependent decrease in percent viability was observed on exposure of embryos to different concentrations of silver nanoparticles with LD 50 of 1.0 µg/ml. The results indicate that silver nanoparticles induce a dose-dependent toxicity in embryos and abrogate normal development.

Journal of Nanoparticle Research, 2014

ABSTRACT In spite of the projected therapeutic potentials of gold nanoparticles (GNP) and silver ... more ABSTRACT In spite of the projected therapeutic potentials of gold nanoparticles (GNP) and silver nanoparticles (SNP), very limited data are available on the interaction of nanoparticles with the biological systems. The present investigation was designed to evaluate as well as compare the subacute toxicity of GNP and SNP. Stable suspensions of GNP and SNP with mean particle diameter 10 and 25 nm, respectively, were prepared. Wistar rats were orally fed SNP (3 mg/kg) or GNP (20 μg/kg), once a day for 21 days. Biochemical indices (creatinine phosphokinase-MB, urea, blood urea nitrogen, aspartate transaminase, alkaline alanine transferase) and histopathological features of the liver, heart, brain, lungs, and kidney were evaluated for signs of toxicity. A significant decline in hepatic and renal function in the GNP treated group was observed as compared to SNP. GNP was found to be relatively more toxic on the lungs and SNP on the myocardial tissue as compared to SNP and GNP treatments, respectively. Interestingly, neither SNP nor GNP adversely affected the basal architecture of the brain as compared to sham. The present study demonstrated that GNP was significantly more noxious on the liver and kidney as compared with SNP.

Journal of Nanoparticle Research, 2016

MGM Journal of Medical Sciences

Although in vivo studies have been modeled using higher mammal systems, the lower vertebrate zebr... more Although in vivo studies have been modeled using higher mammal systems, the lower vertebrate zebrafish (Danio rerio) has gained tremendous attention as a model system. Gold nanoparticles (GNPs) attract the interest of scientists due to their promising potential applications in medicine and targeted drug delivery. The purpose to use GNPs in vivo is that gold in bulk form is nontoxic and apply the positive potentials of nanoparticles. Bulk gold is century-long accepted as a safeto-use metal. Gold in its nanoform has distinct chemical and physical properties and the large amount of surface atoms make GNPs reactive. Moreover, GNPs can potentially access many cellular or subcellular structures, which are unreachable by the larger compound and may induce toxic effects. This paper addresses effects of spherical GNPs of average size 15 nm on reproductive organs after subacute exposure in adult male and female zebrafish. Gold nanoparticles were chemically synthesized and characterized by transmission electron microscope. The primary objective of this study was to determine if exposure to GNPs altered cellular morphology of gonads. The adult fish of both sexes were administered orally with these GNPs at a dose of 20 μg/gm. At the end of the study, quantification of gold content was estimated using two different tools: inductive coupled plasmon-atomic emission spectroscopy (ICP-AES) and inductive coupled plasmon-mass spectroscopy (ICP-MS). No gold metal accumulation was detected in treated group of male and female zebrafish at subacute exposures on estimation through ICP-AES. On analysis using ICP-MS, 0.44 ± 0.18 µg/gm organ weight was detected in ovaries and 4.6 ± 3.20 µg/gm organ weight was detected in testes of treated groups. However, the pattern of accumulation was found to be nonsignificant when compared with the control group at a p-value >0.05. Histopathological analysis of reproductive organs showed no significant changes in cellular morphology of testes and ovaries.

International Journal of Advanced Research, 2016

MGM Journal of Medical Sciences, 2014

Owing to widespread applications, synthesis and characteri zation of silver nanoparticles is rece... more Owing to widespread applications, synthesis and characteri zation of silver nanoparticles is recently attracting considerable attention. Increasing environmental concerns over chemical synthesis routes have resulted in attempts to develop biomimetic approaches. One of them is synthesis using plant parts, which eliminates the elaborate process of maintaining the microbial culture and often found to be kinetically favorable than other bioprocesses. The present study deals with investigating the effect of process microwave irradiation, interaction time on the morpho logy and size of silver nanoparticles synthesized using aqueous extract of Tulsi. Plant extract from ocimum sanctum (Tulsi) was used for the synthesis of silver nanoparticles (AgNPs) from silver nitrate solution. Silver nanoparticles were characterized by UVVis spectrophotometer and scanning electron microscope (SEM). The formation and stability of the reduced silver nanoparticles in the colloidal solution was monitored by UVVis spectrophotometer analysis. Nanoparticles ranges from 20 to 40 nm in size with nearly spherical shape were produced. SEM determination of the brown color stable samples showed the formation of silver nanoparticles and well dispersed nanoparticles could be seen in the samples treated with silver nitrate. These silver nanoparticles have proven to be stable for more than 3 months. It can be inferred from the study that fine tuning the bioprocess parameters will enhance possibilities of desired nanoproduct tail or made for particular applications.

MGM Journal of Medical Sciences, 2014

Genotoxic effects of silver nanoparticles (Ag-np) in a vertebrate model system were investigated.... more Genotoxic effects of silver nanoparticles (Ag-np) in a vertebrate model system were investigated. Effects and accumulation patterns of silver nanoparticles were studied using zebrafish embryos. Nanoparticles of silver were synthesized by chemical reduction of silver nitrate, using sodium borohydride as reducing agent and polyvinyl pyrolidene as a stabilizer. These nanoparticles were characterized by UV/ Vis spectrophotometer (absorption spectra), Transmission electron microscopy and were found to have the size range of 4 to 10 nm. Evaluation of cytotoxicity was carried out at various concentrations to obtain the LD 50 value. Dose dependent decrease in percent viability was observed on exposure of embryos to different concentrations of silver nanoparticles with LD 50 of 1.0 µg/ml. The results indicate that silver nanoparticles induce a dose-dependent toxicity in embryos and abrogate normal development.

Journal of Nanoparticle Research, 2014

ABSTRACT In spite of the projected therapeutic potentials of gold nanoparticles (GNP) and silver ... more ABSTRACT In spite of the projected therapeutic potentials of gold nanoparticles (GNP) and silver nanoparticles (SNP), very limited data are available on the interaction of nanoparticles with the biological systems. The present investigation was designed to evaluate as well as compare the subacute toxicity of GNP and SNP. Stable suspensions of GNP and SNP with mean particle diameter 10 and 25 nm, respectively, were prepared. Wistar rats were orally fed SNP (3 mg/kg) or GNP (20 μg/kg), once a day for 21 days. Biochemical indices (creatinine phosphokinase-MB, urea, blood urea nitrogen, aspartate transaminase, alkaline alanine transferase) and histopathological features of the liver, heart, brain, lungs, and kidney were evaluated for signs of toxicity. A significant decline in hepatic and renal function in the GNP treated group was observed as compared to SNP. GNP was found to be relatively more toxic on the lungs and SNP on the myocardial tissue as compared to SNP and GNP treatments, respectively. Interestingly, neither SNP nor GNP adversely affected the basal architecture of the brain as compared to sham. The present study demonstrated that GNP was significantly more noxious on the liver and kidney as compared with SNP.

Journal of Nanoparticle Research, 2016