Water-soluble copper oxide nanosheets (CuO nanosheets) were synthesized via a chemical reduction ... more Water-soluble copper oxide nanosheets (CuO nanosheets) were synthesized via a chemical reduction method and used as peroxidase enzyme mimetics. The synthesized CuO nanosheets were characterized by using XRD and TEM. The obtained CuO nanosheets in fact possessed an intrinsic enzyme like catalytic activity identical to that found in natural peroxidases, which have applications as detection tools and in water treatment. The copper oxide nanosheets were synthesized as per our reported procedure elsewhere [40]. Briefly, equal volume of aqueous NaOH (0.01 M) and NaBH 4 (0.1 M) were added into a beaker containing the same amount of CuSO 4 (0.01 M) and Quinic acid (0.02 M) mixture and stirred vigorously at room temperature (30 O C). Reaction was continued for about a half an hour with stirring to obtain copper oxide nanosheets. The product was then purified by repeatedly washing with double distilled water and ethanol which was finally dried at 60 O C in hot air oven. Investigation of peroxidase like catalytic activity of CuO nanosheets To examine the peroxidase like catalytic activity of the synthesized CuO nanosheets, the catalytic oxidation of o-dianisidine (as colourless peroxidase substrate, reduced form) was tested in the presence of H 2 O 2 as oxidizing agent. The oxidation of o-dianisidine was carried out using phosphate buffer (p H 7.0) in the presence of CuO nanosheets (100 µl) for 200 seconds at 25 O C. Later, hydrogen peroxide (10mM) was added to start the reaction. The catalytic activity of CuO nanosheets was carefully measured by the development of colour due to oxidation of o-dianisidine using UV-Visible spectrophotometer at 430 nm.
The present study aims a simple chemical synthesis of copper oxide nanosheets (CuO nanosheets) us... more The present study aims a simple chemical synthesis of copper oxide nanosheets (CuO nanosheets) using quinic acid as stabilizing agent at room temperature and studied its catalytic activity in reducing 4-nitrophenol as well as an-timicrobial activity towards bacteria. Synthesized CuO nanosheets were characterized by using XRD and TEM. CuO nanosheets showed good catalytic activity for the reduction of 4-nitrophenol, but poor antibacterial activity towards Gram negative and no activity against Gram positive bacteria.
A green one step synthesis of polyphenols functionalized reduced graphene oxide (RGO) nanosheets ... more A green one step synthesis of polyphenols functionalized reduced graphene oxide (RGO) nanosheets by Terminalia bellirica (T. bellirica) extract was reported herein. The comparative analysis of various characterization results of the formed graphene sheets from graphene oxide disclosed the deoxygenation and subsequent stabilization of nanosheets with plant polyphenols. FTIR spectral data also proved the stabilization of graphene sheets with the oxidized polyphenols of T. bellirica extract.
A green one step facile synthesis of graphene nanosheets byTerminalia chebula(T. chebula) extract... more A green one step facile synthesis of graphene nanosheets byTerminalia chebula(T. chebula) extract mediated reduction of graphite oxide (GO) is reported in this work. This method avoids the use of harmful toxic reducing agents. The comparative results of various characterizations of GO andT. chebulareduced graphene oxide (TCG) provide a strong indication of the exclusion of oxygen containing groups from graphene oxide and successive stabilization of the formed reduced graphene oxide (RGO). The functionalization of reduced graphene oxide with the oxidized polyphenols causes their stability by preventing the aggregation. We also have proposed how the oxidized polyphenols are accountable for the stabilization of the formed graphene sheets.
This research is mainly focusing on one-step biosynthesis of graphene from graphene oxide and its... more This research is mainly focusing on one-step biosynthesis of graphene from graphene oxide and its stabilization using naturally occurring milk protein, casein. The synthesis of casein reduced graphene oxide (CRGO) was completed within 7 h under reflux at 90C with the formation of few layered fine graphene nanosheets. UV–Vis, XRD, XPS analysis data revealed the reduction process of the graphene oxide. Results of FT-IR, HPLC and TEM analysis have shown that the ensuing material consists of graphene decorated with casein molecules. Aspartic acid and glutamic acid residue present in casein molecules are responsible for the reduction of graphene oxide
Diastase, a natural enzyme, was used for the one pot aqueous synthesis of gold nanoparticles (AuN... more Diastase, a natural enzyme, was used for the one pot aqueous synthesis of gold nanoparticles (AuNPs) of tunable size. During the synthetic process, diastase acts concurrently as both a reducing and stabilizing agent, while no additional chemical reagents or surfactants are added. The formation of AuNPs was confirmed by using a UV-visible spectrophotometer, with a characteristic surface plasmon resonance (SPR) band at 530 nm. The size of the diastase-stabilized AuNPs can be easily controlled by changing the quantity of diastase. The produced AuNPs were characterized by using powder X-ray diffraction (XRD),
UV-visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The FTIR spectrum revealed the capping of diastase on the surface of AuNPs. Furthermore, the formed gold nanoparticles are stable for more than three months.In vitro cytotoxicity studies by MTT assay on HCT116 and A549 cancer cells showed that the cytotoxicity of the as synthesized Au nanocolloids depends on their size and dose
Water-soluble copper oxide nanosheets (CuO nanosheets) were synthesized via a chemical reduction ... more Water-soluble copper oxide nanosheets (CuO nanosheets) were synthesized via a chemical reduction method and used as peroxidase enzyme mimetics. The synthesized CuO nanosheets were characterized by using XRD and TEM. The obtained CuO nanosheets in fact possessed an intrinsic enzyme like catalytic activity identical to that found in natural peroxidases, which have applications as detection tools and in water treatment. The copper oxide nanosheets were synthesized as per our reported procedure elsewhere [40]. Briefly, equal volume of aqueous NaOH (0.01 M) and NaBH 4 (0.1 M) were added into a beaker containing the same amount of CuSO 4 (0.01 M) and Quinic acid (0.02 M) mixture and stirred vigorously at room temperature (30 O C). Reaction was continued for about a half an hour with stirring to obtain copper oxide nanosheets. The product was then purified by repeatedly washing with double distilled water and ethanol which was finally dried at 60 O C in hot air oven. Investigation of peroxidase like catalytic activity of CuO nanosheets To examine the peroxidase like catalytic activity of the synthesized CuO nanosheets, the catalytic oxidation of o-dianisidine (as colourless peroxidase substrate, reduced form) was tested in the presence of H 2 O 2 as oxidizing agent. The oxidation of o-dianisidine was carried out using phosphate buffer (p H 7.0) in the presence of CuO nanosheets (100 µl) for 200 seconds at 25 O C. Later, hydrogen peroxide (10mM) was added to start the reaction. The catalytic activity of CuO nanosheets was carefully measured by the development of colour due to oxidation of o-dianisidine using UV-Visible spectrophotometer at 430 nm.
The present study aims a simple chemical synthesis of copper oxide nanosheets (CuO nanosheets) us... more The present study aims a simple chemical synthesis of copper oxide nanosheets (CuO nanosheets) using quinic acid as stabilizing agent at room temperature and studied its catalytic activity in reducing 4-nitrophenol as well as an-timicrobial activity towards bacteria. Synthesized CuO nanosheets were characterized by using XRD and TEM. CuO nanosheets showed good catalytic activity for the reduction of 4-nitrophenol, but poor antibacterial activity towards Gram negative and no activity against Gram positive bacteria.
A green one step synthesis of polyphenols functionalized reduced graphene oxide (RGO) nanosheets ... more A green one step synthesis of polyphenols functionalized reduced graphene oxide (RGO) nanosheets by Terminalia bellirica (T. bellirica) extract was reported herein. The comparative analysis of various characterization results of the formed graphene sheets from graphene oxide disclosed the deoxygenation and subsequent stabilization of nanosheets with plant polyphenols. FTIR spectral data also proved the stabilization of graphene sheets with the oxidized polyphenols of T. bellirica extract.
A green one step facile synthesis of graphene nanosheets byTerminalia chebula(T. chebula) extract... more A green one step facile synthesis of graphene nanosheets byTerminalia chebula(T. chebula) extract mediated reduction of graphite oxide (GO) is reported in this work. This method avoids the use of harmful toxic reducing agents. The comparative results of various characterizations of GO andT. chebulareduced graphene oxide (TCG) provide a strong indication of the exclusion of oxygen containing groups from graphene oxide and successive stabilization of the formed reduced graphene oxide (RGO). The functionalization of reduced graphene oxide with the oxidized polyphenols causes their stability by preventing the aggregation. We also have proposed how the oxidized polyphenols are accountable for the stabilization of the formed graphene sheets.
This research is mainly focusing on one-step biosynthesis of graphene from graphene oxide and its... more This research is mainly focusing on one-step biosynthesis of graphene from graphene oxide and its stabilization using naturally occurring milk protein, casein. The synthesis of casein reduced graphene oxide (CRGO) was completed within 7 h under reflux at 90C with the formation of few layered fine graphene nanosheets. UV–Vis, XRD, XPS analysis data revealed the reduction process of the graphene oxide. Results of FT-IR, HPLC and TEM analysis have shown that the ensuing material consists of graphene decorated with casein molecules. Aspartic acid and glutamic acid residue present in casein molecules are responsible for the reduction of graphene oxide
Diastase, a natural enzyme, was used for the one pot aqueous synthesis of gold nanoparticles (AuN... more Diastase, a natural enzyme, was used for the one pot aqueous synthesis of gold nanoparticles (AuNPs) of tunable size. During the synthetic process, diastase acts concurrently as both a reducing and stabilizing agent, while no additional chemical reagents or surfactants are added. The formation of AuNPs was confirmed by using a UV-visible spectrophotometer, with a characteristic surface plasmon resonance (SPR) band at 530 nm. The size of the diastase-stabilized AuNPs can be easily controlled by changing the quantity of diastase. The produced AuNPs were characterized by using powder X-ray diffraction (XRD),
UV-visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The FTIR spectrum revealed the capping of diastase on the surface of AuNPs. Furthermore, the formed gold nanoparticles are stable for more than three months.In vitro cytotoxicity studies by MTT assay on HCT116 and A549 cancer cells showed that the cytotoxicity of the as synthesized Au nanocolloids depends on their size and dose
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Papers by Sireesh Maddineni
mediated reduction of graphite oxide (GO) is reported in this work. This method avoids the use of harmful
toxic reducing agents. The comparative results of various characterizations of GO andT. chebulareduced
graphene oxide (TCG) provide a strong indication of the exclusion of oxygen containing groups from
graphene oxide and successive stabilization of the formed reduced graphene oxide (RGO). The
functionalization of reduced graphene oxide with the oxidized polyphenols causes their stability by
preventing the aggregation. We also have proposed how the oxidized polyphenols are accountable for
the stabilization of the formed graphene sheets.
UV-visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The FTIR spectrum revealed the capping of diastase on the surface of AuNPs. Furthermore, the formed gold nanoparticles are stable for more than three months.In vitro cytotoxicity studies by MTT assay on HCT116 and A549 cancer cells showed that the cytotoxicity of the as synthesized Au nanocolloids depends on their size and dose
mediated reduction of graphite oxide (GO) is reported in this work. This method avoids the use of harmful
toxic reducing agents. The comparative results of various characterizations of GO andT. chebulareduced
graphene oxide (TCG) provide a strong indication of the exclusion of oxygen containing groups from
graphene oxide and successive stabilization of the formed reduced graphene oxide (RGO). The
functionalization of reduced graphene oxide with the oxidized polyphenols causes their stability by
preventing the aggregation. We also have proposed how the oxidized polyphenols are accountable for
the stabilization of the formed graphene sheets.
UV-visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR) and transmission electron microscopy (TEM). The FTIR spectrum revealed the capping of diastase on the surface of AuNPs. Furthermore, the formed gold nanoparticles are stable for more than three months.In vitro cytotoxicity studies by MTT assay on HCT116 and A549 cancer cells showed that the cytotoxicity of the as synthesized Au nanocolloids depends on their size and dose