jagriti narang - Academia.edu (original) (raw)

Papers by jagriti narang

Research paper thumbnail of Magnetic resonance estimation of longitudinal relaxation time (T1) in spoiled gradient echo using an adaptive neural network

... of Radiology, Henry Ford Hospital; Quan Jiang - Dept. of Neurology, Henry Ford Hospital; TomM... more ... of Radiology, Henry Ford Hospital; Quan Jiang - Dept. of Neurology, Henry Ford Hospital; TomMikkelsen - Dept. of Neurosurgery, Henry Ford Hospital; James Ewing - Dept. of Neurology, HenryFord Hospital, Dept. of Neurology, Wayne State University, and Dept. ...

Research paper thumbnail of Immobilization of rat brain acetylcholinesterase on porous gold-nanoparticle–CaCO 3 hybrid material modified Au electrode for detection of organophosphorous insecticides

International Journal of Biological Macromolecules, 2011

A novel, highly sensitive amperometric biosensor for detection of organophosphorus (OP) compounds... more A novel, highly sensitive amperometric biosensor for detection of organophosphorus (OP) compounds has been constructed, based on rat brain acetylcholinesterase (AChE) immobilized onto nanocomposite of ZnS-nanoparticles (ZnSNPs) and poly(indole-5-carboxylic acid) electrodeposited on Au electrode. In the presence of acetylthiocholine chloride (ATCl) as a substrate, ZnSNPs promoted electron transfer reactions at a lower potential and catalyzed electrochemical oxidation of enzymatically formed thiocholine, thus increasing detection sensitivity. Under optimum conditions (phosphate buffer, pH 7.5 and 30 • C), the inhibition of AChE by malathion and chlorpyrifos was proportional to their concentrations in the range, 0.1-50 nM and 1.5-40 nM, respectively. The biosensor determined malathion and chlorpyrifos in spiked tap water samples with a acceptable accuracy (95-100%). The enzyme electrode had long-storage stability (50% retention of initial activity within 2 months, when stored at 4 • C).

Research paper thumbnail of Fabrication of multiwalled carbon nanotubes/polyaniline modified Au electrode for ascorbic acid determination

Analyst, 2011

An ascorbate oxidase (AsOx) (E.C.1.10.3.3) purified from Lagenaria siceraria fruit was immobilize... more An ascorbate oxidase (AsOx) (E.C.1.10.3.3) purified from Lagenaria siceraria fruit was immobilized covalently onto a carboxylated multiwalled carbon nanotubes and polyaniline (c-MWCNT/PANI) layer electrochemically deposited on the surface of an Au electrode. The diffusion coefficient of ascorbic acid was determined as 3.05 × 10(-4) cm(2) s(-1). The behavior of different electrolytes on electro-deposition was also studied. An ascorbate biosensor was fabricated using a AsOx/c-MWCNT/PANI/Au electrode as a working electrode, Ag/AgCl (3 M/saturated KCl) as standard and Pt wire as an auxiliary electrode connected through a potentiostat. Linear range, response time and detection limit were 2-206 μM, 2 s and 0.9 μM respectively. The biosensor showed optimum response at pH 5.8 and in a broader temperature range (30-45 °C), when polarized at +0.6 V. The biosensor was employed for determination of ascorbic acid level in sera, fruit juices and vitamin C tablets. The sensor was evaluated with 91% recovery of added ascorbic acid in sera and 6.5% and 11.4% within and between batch coefficients of variation respectively for five serum samples. There was a good correlation (r = 0.98) between fruit juice ascorbic acid values by the standard 2,6-dichlorophenolindophenol (DCPIP) method and the present method. The enzyme electrode was used 200 times over a period of two months, when stored at 4 °C. The biosensor has advantages over earlier enzyme sensors in that it has no leakage of enzyme, due to the covalent coupling of enzyme with the support, lower response time, wider working range, higher storage stability and no interference by serum substances.

Research paper thumbnail of Construction of a triglyceride amperometric biosensor based on chitosan–ZnO nanocomposite film

International Journal of Biological Macromolecules, 2011

a b s t r a c t A method is described for construction of a novel amperometric triglyceride (TG) ... more a b s t r a c t A method is described for construction of a novel amperometric triglyceride (TG) biosensor based on covalent co-immobilization of lipase, glycerol kinase (GK) and glycerol-3-phosphate oxidase (GPO) onto chitosan (CHIT) and zinc oxide nanoparticles (ZnONPs) composite film deposited on the surface of Pt electrode. The enzymes-ZnONPs-CHIT composite was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The sensor showed optimum response within 6 s at pH 7.5 and temperature of 35 • C. The sensor measures current due to electrons generated at 0.4 V against Ag/AgCl from H 2 O 2 , which is produced from triolein by co-immobilized enzymes. A linear relationship was obtained between a wide triolein concentration range (50-650 mg/dl) and current (mA) under optimum conditions. The biosensor showed high sensitivity, low detection limit (20 mg/dl) and good storage stability (half-life of 7 months at 4 • C). The biosensor was unaffected modified by a number of serum substances at their physiological concentrations. The biosensor was evaluated and employed for determination of TG in sera in apparently healthy subjects and persons suffering from hypertriglyceridemia.

Research paper thumbnail of Determination of serum triglyceride by enzyme electrode using covalently immobilized enzyme on egg shell membrane

International Journal of Biological Macromolecules, 2010

A mixture of commercial lipase, glycerol kinase and glycerol-3-phosphate oxidase was co-immobiliz... more A mixture of commercial lipase, glycerol kinase and glycerol-3-phosphate oxidase was co-immobilized onto egg shell membrane through covalent coupling. A method is described for fabrication of a triglyceride (TG) biosensor using egg shell membrane bound enzymes. The biosensor measured current, i.e. flow of electrons generated from H 2 O 2 , maximally when polarized at 0.4 V. The biosensor showed optimum response within 10 sec at pH 7.0 and 35 • C. The current was in proportion to concentration of TG in the range 0.56-2.25 mM. An amperometric method was developed for determination of TG employing this enzyme electrode. The minimum detection limit of the method was 0.28 mM. The analytic recovery of added TG was 95.00% and 96.50%. Within batch and between batch coefficients of variations (CV) were <2.14% and <3.48% respectively. A good correlation (r = 0.985) was obtained between serum TG level by standard enzymic colorimetric method and the present method. Serum substances such as urea, uric acid, glucose, cholesterol, ascorbic acid and pyruvic acid had no interference. The enzyme electrode was used 200 times over a period of 70 days without any considerable loss of activity, when stored at 4 • C.

Research paper thumbnail of Construction of an amperometric triglyceride biosensor using PVA membrane bound enzymes

Clinical Biochemistry, 2010

A method is described for construction of an amperometric triglyceride (TG) biosensor using PVA m... more A method is described for construction of an amperometric triglyceride (TG) biosensor using PVA membrane bound enzymes. A mixture of commercial lipase, glycerol kinase, glycerol-3-phosphate oxidase and horseradish peroxidase was co-immobilized onto polyvinyl alcohol (PVA) membrane through glutaraldehyde coupling. The biosensor measures current when polarized at 0.4 V. The sensor showed optimum response within 2 s at pH 7.0 and 25 degrees C. The current (mA) was in proportion to concentration of TG in the range 0.56-2.25 mM. The minimum detection limit of the method was 0.21 mM. The analytic recovery of added TG was 94.3%. Within batch and between batch coefficients of variations (CV) were &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;5.85% and &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;4.13%, respectively. A good correlation (r=0.99) was found. Among various serum substances tested, only cholesterol caused slight stimulation (20%). An amperometric method was developed for determination of TG employing this enzyme electrode.

Research paper thumbnail of A nylon membrane based amperometric biosensor for polyphenol determination

Journal of Molecular Catalysis B-enzymatic, 2011

A nylon membrane based amperometric biosensor employing banana fruit polyphenol oxidase (PPO) is ... more A nylon membrane based amperometric biosensor employing banana fruit polyphenol oxidase (PPO) is presented for polyphenol detection. Nylon membrane was first activated and then coupled with chitosan. PPO was covalently attached to this membrane through glutaraldehyde coupling. The membrane bioconjugate was characterized by scanning electron microscopy (SEM) and Fourier Transform Infrared (FTIR) study and then mounted onto Au electrode using

Research paper thumbnail of An amperometric polyphenol biosensor based on polyvinyl chloride membrane

Analytical Methods, 2010

An amperometric polyphenol biosensor based on polyvinyl chloride membrane Sheetal Chawla, Jagriti... more An amperometric polyphenol biosensor based on polyvinyl chloride membrane Sheetal Chawla, Jagriti Narang and CS Pundir* ... Health Perspect., 1989, 82, 253–258. 3 JW Yager, DA Eastmond, ML Robertson, WM Paradisina and MT Smith, Cancer Res., 1990, 15, 393–399. ...

Research paper thumbnail of Immobilization of rat brain acetylcholinesterase on ZnS and poly(indole-5-carboxylic acid) modified Au electrode for detection of organophosphorus insecticides

Biosensors & Bioelectronics, 2011

A novel, highly sensitive amperometric biosensor for detection of organophosphorus (OP) compounds... more A novel, highly sensitive amperometric biosensor for detection of organophosphorus (OP) compounds has been constructed, based on rat brain acetylcholinesterase (AChE) immobilized onto nanocomposite of ZnS-nanoparticles (ZnSNPs) and poly(indole-5-carboxylic acid) electrodeposited on Au electrode. In the presence of acetylthiocholine chloride (ATCl) as a substrate, ZnSNPs promoted electron transfer reactions at a lower potential and catalyzed electrochemical oxidation of enzymatically formed thiocholine, thus increasing detection sensitivity. Under optimum conditions (phosphate buffer, pH 7.5 and 30 • C), the inhibition of AChE by malathion and chlorpyrifos was proportional to their concentrations in the range, 0.1-50 nM and 1.5-40 nM, respectively. The biosensor determined malathion and chlorpyrifos in spiked tap water samples with a acceptable accuracy (95-100%). The enzyme electrode had long-storage stability (50% retention of initial activity within 2 months, when stored at 4 • C).

Research paper thumbnail of A non-enzymatic sensor for hydrogen peroxide based on polyaniline, multiwalled carbon nanotubes and gold nanoparticles modified Au electrode

Analyst, 2011

We describe the construction of a polyaniline (PANI), multiwalled carbon nanotubes (MWCNTs) and g... more We describe the construction of a polyaniline (PANI), multiwalled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) modified Au electrode for determination of hydrogen peroxide without using peroxidase (HRP). The AuNPs/MWCNT/PANI composite ...

Research paper thumbnail of Fabrication of an Amperometric Triglyceride Biosensor based on PVC Membrane

Analytical Letters, 2010

ABSTRACT An amperometric enzyme sensor for determination of triglycerides (TGs) was constructed b... more ABSTRACT An amperometric enzyme sensor for determination of triglycerides (TGs) was constructed by mounting polyvinyl chloride (PVC) membrane bound lipase, glycerol kinase (GK), glycerol-3-phosphate oxidase (GPO), and horseradish peroxidase (HRP) on a platinum electrode (working electrode), then connecting it to electrometer along with Ag/AgCl reference electrode and Cu auxiliary electrode. The biosensor measures the electrons generated from H2O2 at 0.4V, which is formed from triolein/triglycerides by co-immobilized lipase, GK, GPO, and HRP. The concentration of triolein/TG was directly proportional to the current measured. The enzyme electrode showed optimum response when operated at 25 degrees C in 0.1M sodium phosphate buffer, pH 7.5, for 30s. A linear relationship was obtained between triolein concentration ranging from 0.56 to 2.25mM and amount of current (mA). The minimum detection limit of the method was 0.11mM. The levels of TG in serum of apparently healthy persons and persons suffering from cardiovascular disease and pancreatitis, as measured by this sensor, were in the range 50-216mg/dl and 200-499mg/dl respectively. The analytical recovery of added triolein was 85.2%. Within-batch and between-batch coefficients of variation were2.53% and 3.21% respectively. A good correlation (r=0.91) was found between serum TG values obtained by commercial enzymic colorimetric and the present method. Among the various serum substances tested, only cholesterol and bilirubin caused inhibition, 15% and 8% respectively. The enzyme electrode was used 100 times over 40 days without any considerable loss of activity when stored at 4 degrees C.

Research paper thumbnail of A highly sensitive non-enzymatic ascorbate sensor based on copper nanoparticles bound to multi walled carbon nanotubes and polyaniline composite

Lancet, 2011

a b s t r a c t A novel, stable and highly sensitive non-enzymatic ascorbic acid sensor was devel... more a b s t r a c t A novel, stable and highly sensitive non-enzymatic ascorbic acid sensor was developed using copper nanoparticles (CuNPs), carboxylated multi-walled carbon nanotubes (MWCNTs) and polyaniline (PANI) composite electrodeposited on gold electrode. The modified Au electrode was characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry and impedance spectroscopy. The linear sweep voltammetry peak current showed a linear dependence on the ascorbic acid concentration and a linear calibration curve was obtained in the range, 5-600 M of ascorbic acid with a correlation coefficient (r) of 0.998. The sensors response time was less than 2 s and detection limit was 1.0 M (at signal/noise = 3). When tested with serum, fruits and vegetables, the sensor exhibited high electrocatalytic activity, fast response and good selectivity against common interfering species, suggesting its potential to be developed as a non-enzymatic ascorbic acid sensor.

Research paper thumbnail of Magnetic resonance estimation of longitudinal relaxation time (T1) in spoiled gradient echo using an adaptive neural network

... of Radiology, Henry Ford Hospital; Quan Jiang - Dept. of Neurology, Henry Ford Hospital; TomM... more ... of Radiology, Henry Ford Hospital; Quan Jiang - Dept. of Neurology, Henry Ford Hospital; TomMikkelsen - Dept. of Neurosurgery, Henry Ford Hospital; James Ewing - Dept. of Neurology, HenryFord Hospital, Dept. of Neurology, Wayne State University, and Dept. ...

Research paper thumbnail of Immobilization of rat brain acetylcholinesterase on porous gold-nanoparticle–CaCO 3 hybrid material modified Au electrode for detection of organophosphorous insecticides

International Journal of Biological Macromolecules, 2011

A novel, highly sensitive amperometric biosensor for detection of organophosphorus (OP) compounds... more A novel, highly sensitive amperometric biosensor for detection of organophosphorus (OP) compounds has been constructed, based on rat brain acetylcholinesterase (AChE) immobilized onto nanocomposite of ZnS-nanoparticles (ZnSNPs) and poly(indole-5-carboxylic acid) electrodeposited on Au electrode. In the presence of acetylthiocholine chloride (ATCl) as a substrate, ZnSNPs promoted electron transfer reactions at a lower potential and catalyzed electrochemical oxidation of enzymatically formed thiocholine, thus increasing detection sensitivity. Under optimum conditions (phosphate buffer, pH 7.5 and 30 • C), the inhibition of AChE by malathion and chlorpyrifos was proportional to their concentrations in the range, 0.1-50 nM and 1.5-40 nM, respectively. The biosensor determined malathion and chlorpyrifos in spiked tap water samples with a acceptable accuracy (95-100%). The enzyme electrode had long-storage stability (50% retention of initial activity within 2 months, when stored at 4 • C).

Research paper thumbnail of Fabrication of multiwalled carbon nanotubes/polyaniline modified Au electrode for ascorbic acid determination

Analyst, 2011

An ascorbate oxidase (AsOx) (E.C.1.10.3.3) purified from Lagenaria siceraria fruit was immobilize... more An ascorbate oxidase (AsOx) (E.C.1.10.3.3) purified from Lagenaria siceraria fruit was immobilized covalently onto a carboxylated multiwalled carbon nanotubes and polyaniline (c-MWCNT/PANI) layer electrochemically deposited on the surface of an Au electrode. The diffusion coefficient of ascorbic acid was determined as 3.05 × 10(-4) cm(2) s(-1). The behavior of different electrolytes on electro-deposition was also studied. An ascorbate biosensor was fabricated using a AsOx/c-MWCNT/PANI/Au electrode as a working electrode, Ag/AgCl (3 M/saturated KCl) as standard and Pt wire as an auxiliary electrode connected through a potentiostat. Linear range, response time and detection limit were 2-206 μM, 2 s and 0.9 μM respectively. The biosensor showed optimum response at pH 5.8 and in a broader temperature range (30-45 °C), when polarized at +0.6 V. The biosensor was employed for determination of ascorbic acid level in sera, fruit juices and vitamin C tablets. The sensor was evaluated with 91% recovery of added ascorbic acid in sera and 6.5% and 11.4% within and between batch coefficients of variation respectively for five serum samples. There was a good correlation (r = 0.98) between fruit juice ascorbic acid values by the standard 2,6-dichlorophenolindophenol (DCPIP) method and the present method. The enzyme electrode was used 200 times over a period of two months, when stored at 4 °C. The biosensor has advantages over earlier enzyme sensors in that it has no leakage of enzyme, due to the covalent coupling of enzyme with the support, lower response time, wider working range, higher storage stability and no interference by serum substances.

Research paper thumbnail of Construction of a triglyceride amperometric biosensor based on chitosan–ZnO nanocomposite film

International Journal of Biological Macromolecules, 2011

a b s t r a c t A method is described for construction of a novel amperometric triglyceride (TG) ... more a b s t r a c t A method is described for construction of a novel amperometric triglyceride (TG) biosensor based on covalent co-immobilization of lipase, glycerol kinase (GK) and glycerol-3-phosphate oxidase (GPO) onto chitosan (CHIT) and zinc oxide nanoparticles (ZnONPs) composite film deposited on the surface of Pt electrode. The enzymes-ZnONPs-CHIT composite was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The sensor showed optimum response within 6 s at pH 7.5 and temperature of 35 • C. The sensor measures current due to electrons generated at 0.4 V against Ag/AgCl from H 2 O 2 , which is produced from triolein by co-immobilized enzymes. A linear relationship was obtained between a wide triolein concentration range (50-650 mg/dl) and current (mA) under optimum conditions. The biosensor showed high sensitivity, low detection limit (20 mg/dl) and good storage stability (half-life of 7 months at 4 • C). The biosensor was unaffected modified by a number of serum substances at their physiological concentrations. The biosensor was evaluated and employed for determination of TG in sera in apparently healthy subjects and persons suffering from hypertriglyceridemia.

Research paper thumbnail of Determination of serum triglyceride by enzyme electrode using covalently immobilized enzyme on egg shell membrane

International Journal of Biological Macromolecules, 2010

A mixture of commercial lipase, glycerol kinase and glycerol-3-phosphate oxidase was co-immobiliz... more A mixture of commercial lipase, glycerol kinase and glycerol-3-phosphate oxidase was co-immobilized onto egg shell membrane through covalent coupling. A method is described for fabrication of a triglyceride (TG) biosensor using egg shell membrane bound enzymes. The biosensor measured current, i.e. flow of electrons generated from H 2 O 2 , maximally when polarized at 0.4 V. The biosensor showed optimum response within 10 sec at pH 7.0 and 35 • C. The current was in proportion to concentration of TG in the range 0.56-2.25 mM. An amperometric method was developed for determination of TG employing this enzyme electrode. The minimum detection limit of the method was 0.28 mM. The analytic recovery of added TG was 95.00% and 96.50%. Within batch and between batch coefficients of variations (CV) were <2.14% and <3.48% respectively. A good correlation (r = 0.985) was obtained between serum TG level by standard enzymic colorimetric method and the present method. Serum substances such as urea, uric acid, glucose, cholesterol, ascorbic acid and pyruvic acid had no interference. The enzyme electrode was used 200 times over a period of 70 days without any considerable loss of activity, when stored at 4 • C.

Research paper thumbnail of Construction of an amperometric triglyceride biosensor using PVA membrane bound enzymes

Clinical Biochemistry, 2010

A method is described for construction of an amperometric triglyceride (TG) biosensor using PVA m... more A method is described for construction of an amperometric triglyceride (TG) biosensor using PVA membrane bound enzymes. A mixture of commercial lipase, glycerol kinase, glycerol-3-phosphate oxidase and horseradish peroxidase was co-immobilized onto polyvinyl alcohol (PVA) membrane through glutaraldehyde coupling. The biosensor measures current when polarized at 0.4 V. The sensor showed optimum response within 2 s at pH 7.0 and 25 degrees C. The current (mA) was in proportion to concentration of TG in the range 0.56-2.25 mM. The minimum detection limit of the method was 0.21 mM. The analytic recovery of added TG was 94.3%. Within batch and between batch coefficients of variations (CV) were &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;5.85% and &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt;4.13%, respectively. A good correlation (r=0.99) was found. Among various serum substances tested, only cholesterol caused slight stimulation (20%). An amperometric method was developed for determination of TG employing this enzyme electrode.

Research paper thumbnail of A nylon membrane based amperometric biosensor for polyphenol determination

Journal of Molecular Catalysis B-enzymatic, 2011

A nylon membrane based amperometric biosensor employing banana fruit polyphenol oxidase (PPO) is ... more A nylon membrane based amperometric biosensor employing banana fruit polyphenol oxidase (PPO) is presented for polyphenol detection. Nylon membrane was first activated and then coupled with chitosan. PPO was covalently attached to this membrane through glutaraldehyde coupling. The membrane bioconjugate was characterized by scanning electron microscopy (SEM) and Fourier Transform Infrared (FTIR) study and then mounted onto Au electrode using

Research paper thumbnail of An amperometric polyphenol biosensor based on polyvinyl chloride membrane

Analytical Methods, 2010

An amperometric polyphenol biosensor based on polyvinyl chloride membrane Sheetal Chawla, Jagriti... more An amperometric polyphenol biosensor based on polyvinyl chloride membrane Sheetal Chawla, Jagriti Narang and CS Pundir* ... Health Perspect., 1989, 82, 253–258. 3 JW Yager, DA Eastmond, ML Robertson, WM Paradisina and MT Smith, Cancer Res., 1990, 15, 393–399. ...

Research paper thumbnail of Immobilization of rat brain acetylcholinesterase on ZnS and poly(indole-5-carboxylic acid) modified Au electrode for detection of organophosphorus insecticides

Biosensors & Bioelectronics, 2011

A novel, highly sensitive amperometric biosensor for detection of organophosphorus (OP) compounds... more A novel, highly sensitive amperometric biosensor for detection of organophosphorus (OP) compounds has been constructed, based on rat brain acetylcholinesterase (AChE) immobilized onto nanocomposite of ZnS-nanoparticles (ZnSNPs) and poly(indole-5-carboxylic acid) electrodeposited on Au electrode. In the presence of acetylthiocholine chloride (ATCl) as a substrate, ZnSNPs promoted electron transfer reactions at a lower potential and catalyzed electrochemical oxidation of enzymatically formed thiocholine, thus increasing detection sensitivity. Under optimum conditions (phosphate buffer, pH 7.5 and 30 • C), the inhibition of AChE by malathion and chlorpyrifos was proportional to their concentrations in the range, 0.1-50 nM and 1.5-40 nM, respectively. The biosensor determined malathion and chlorpyrifos in spiked tap water samples with a acceptable accuracy (95-100%). The enzyme electrode had long-storage stability (50% retention of initial activity within 2 months, when stored at 4 • C).

Research paper thumbnail of A non-enzymatic sensor for hydrogen peroxide based on polyaniline, multiwalled carbon nanotubes and gold nanoparticles modified Au electrode

Analyst, 2011

We describe the construction of a polyaniline (PANI), multiwalled carbon nanotubes (MWCNTs) and g... more We describe the construction of a polyaniline (PANI), multiwalled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) modified Au electrode for determination of hydrogen peroxide without using peroxidase (HRP). The AuNPs/MWCNT/PANI composite ...

Research paper thumbnail of Fabrication of an Amperometric Triglyceride Biosensor based on PVC Membrane

Analytical Letters, 2010

ABSTRACT An amperometric enzyme sensor for determination of triglycerides (TGs) was constructed b... more ABSTRACT An amperometric enzyme sensor for determination of triglycerides (TGs) was constructed by mounting polyvinyl chloride (PVC) membrane bound lipase, glycerol kinase (GK), glycerol-3-phosphate oxidase (GPO), and horseradish peroxidase (HRP) on a platinum electrode (working electrode), then connecting it to electrometer along with Ag/AgCl reference electrode and Cu auxiliary electrode. The biosensor measures the electrons generated from H2O2 at 0.4V, which is formed from triolein/triglycerides by co-immobilized lipase, GK, GPO, and HRP. The concentration of triolein/TG was directly proportional to the current measured. The enzyme electrode showed optimum response when operated at 25 degrees C in 0.1M sodium phosphate buffer, pH 7.5, for 30s. A linear relationship was obtained between triolein concentration ranging from 0.56 to 2.25mM and amount of current (mA). The minimum detection limit of the method was 0.11mM. The levels of TG in serum of apparently healthy persons and persons suffering from cardiovascular disease and pancreatitis, as measured by this sensor, were in the range 50-216mg/dl and 200-499mg/dl respectively. The analytical recovery of added triolein was 85.2%. Within-batch and between-batch coefficients of variation were2.53% and 3.21% respectively. A good correlation (r=0.91) was found between serum TG values obtained by commercial enzymic colorimetric and the present method. Among the various serum substances tested, only cholesterol and bilirubin caused inhibition, 15% and 8% respectively. The enzyme electrode was used 100 times over 40 days without any considerable loss of activity when stored at 4 degrees C.

Research paper thumbnail of A highly sensitive non-enzymatic ascorbate sensor based on copper nanoparticles bound to multi walled carbon nanotubes and polyaniline composite

Lancet, 2011

a b s t r a c t A novel, stable and highly sensitive non-enzymatic ascorbic acid sensor was devel... more a b s t r a c t A novel, stable and highly sensitive non-enzymatic ascorbic acid sensor was developed using copper nanoparticles (CuNPs), carboxylated multi-walled carbon nanotubes (MWCNTs) and polyaniline (PANI) composite electrodeposited on gold electrode. The modified Au electrode was characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry and impedance spectroscopy. The linear sweep voltammetry peak current showed a linear dependence on the ascorbic acid concentration and a linear calibration curve was obtained in the range, 5-600 M of ascorbic acid with a correlation coefficient (r) of 0.998. The sensors response time was less than 2 s and detection limit was 1.0 M (at signal/noise = 3). When tested with serum, fruits and vegetables, the sensor exhibited high electrocatalytic activity, fast response and good selectivity against common interfering species, suggesting its potential to be developed as a non-enzymatic ascorbic acid sensor.