Limits...
Development of an electrochemical-based aspartate aminotransferase nanoparticle ir-C biosensor for screening of liver diseases.

Hsueh CJ, Wang JH, Dai L, Liu CC - Biosensors (Basel) (2012)

Bottom Line: Aspartate aminotransaminase (AST) is a hepatocelluar enzyme released into the bloodstream when hepatic cells are damaged, resulting in elevated blood levels of AST.This biosensor is capable of measuring AST levels in a phosphate buffer and undiluted human serum over the concentration range of 0 to 0.89 μg/mL AST concentration (corresponding to 0-250 UL-1 specific activity).The biosensor operates at relatively low oxidation potential (+0.3 volt (V) versus the printed Ag/AgCl), minimizing any potential chemical interference in human serum.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering and Electronics Design Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA. cxh300@case.edu.

ABSTRACT
Aspartate aminotransaminase (AST) is a hepatocelluar enzyme released into the bloodstream when hepatic cells are damaged, resulting in elevated blood levels of AST. A single use, disposable biosensor prototype, composed of catalytic iridium nano-particles dispersed on carbon paste, was developed to detect enzymatically-produced H2O2 in AST-mediated reactions. This biosensor is capable of measuring AST levels in a phosphate buffer and undiluted human serum over the concentration range of 0 to 0.89 μg/mL AST concentration (corresponding to 0-250 UL-1 specific activity). The biosensor operates at relatively low oxidation potential (+0.3 volt (V) versus the printed Ag/AgCl), minimizing any potential chemical interference in human serum. The measurements of AST in human serum using the biosensor compared well with those measured by standard hospital spectrophotometric assays. This Ir-C biosensor may be useful for AST measurements in the clinical environment.

No MeSH data available.


Related in: MedlinePlus

Cyclic voltammograms of background (0 mM L-glutamate) and 0.4 mM NH4OH, and 0.4 mM L-glutamate in a basic testing solution in the absence or presence of 0.05U/µL GluOx as testing solution (each measurement repeated 3 times using a fresh sensor).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4263573&req=5

biosensors-02-00234-f002: Cyclic voltammograms of background (0 mM L-glutamate) and 0.4 mM NH4OH, and 0.4 mM L-glutamate in a basic testing solution in the absence or presence of 0.05U/µL GluOx as testing solution (each measurement repeated 3 times using a fresh sensor).

Mentions: L-aspartate and α-ketoglutarate in Scheme 2 in the presence of AST produced L-glutamate. L-glutamate reacted with glutamate oxidase producing H2O2. The L-glutamate concentration was then quantified by measuring the enzymatically-generated H2O2. In a typical run, 0.5 µL of enzyme solution (0.05 U/µL GluOx) was applied to the biosensor (Figure 1). 5 µL of L-glutamate testing solution with variable concentration 0–0.4 mM was then added to the biosensor. The reagents were prepared as 0.1 M pH 7.4 phosphate buffer solutions with 150 mM KCl supporting electrolyte. Cyclic voltammetry was performed with the scan ranges −0.1 to +0.4 V at a scan rate of 10 mV per second to identify the oxidation potential of H2O2 in the test medium. Figure 2 shows that the substrate (L-glutamate) and product (NH4OH) in Scheme 2 did not contribute to any oxidized currents based on the cyclic voltammograms. As shown in Figure 2 at +0.3 V versus the printed Ag/AgCl reference electrode, the oxidation current of H2O2 could be used to quantify the L-glutamate concentration. The low oxidation potential of H2O2 at +0.3 V minimized the interference from oxidation of other species.


Development of an electrochemical-based aspartate aminotransferase nanoparticle ir-C biosensor for screening of liver diseases.

Hsueh CJ, Wang JH, Dai L, Liu CC - Biosensors (Basel) (2012)

Cyclic voltammograms of background (0 mM L-glutamate) and 0.4 mM NH4OH, and 0.4 mM L-glutamate in a basic testing solution in the absence or presence of 0.05U/µL GluOx as testing solution (each measurement repeated 3 times using a fresh sensor).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4263573&req=5

biosensors-02-00234-f002: Cyclic voltammograms of background (0 mM L-glutamate) and 0.4 mM NH4OH, and 0.4 mM L-glutamate in a basic testing solution in the absence or presence of 0.05U/µL GluOx as testing solution (each measurement repeated 3 times using a fresh sensor).
Mentions: L-aspartate and α-ketoglutarate in Scheme 2 in the presence of AST produced L-glutamate. L-glutamate reacted with glutamate oxidase producing H2O2. The L-glutamate concentration was then quantified by measuring the enzymatically-generated H2O2. In a typical run, 0.5 µL of enzyme solution (0.05 U/µL GluOx) was applied to the biosensor (Figure 1). 5 µL of L-glutamate testing solution with variable concentration 0–0.4 mM was then added to the biosensor. The reagents were prepared as 0.1 M pH 7.4 phosphate buffer solutions with 150 mM KCl supporting electrolyte. Cyclic voltammetry was performed with the scan ranges −0.1 to +0.4 V at a scan rate of 10 mV per second to identify the oxidation potential of H2O2 in the test medium. Figure 2 shows that the substrate (L-glutamate) and product (NH4OH) in Scheme 2 did not contribute to any oxidized currents based on the cyclic voltammograms. As shown in Figure 2 at +0.3 V versus the printed Ag/AgCl reference electrode, the oxidation current of H2O2 could be used to quantify the L-glutamate concentration. The low oxidation potential of H2O2 at +0.3 V minimized the interference from oxidation of other species.

Bottom Line: Aspartate aminotransaminase (AST) is a hepatocelluar enzyme released into the bloodstream when hepatic cells are damaged, resulting in elevated blood levels of AST.This biosensor is capable of measuring AST levels in a phosphate buffer and undiluted human serum over the concentration range of 0 to 0.89 μg/mL AST concentration (corresponding to 0-250 UL-1 specific activity).The biosensor operates at relatively low oxidation potential (+0.3 volt (V) versus the printed Ag/AgCl), minimizing any potential chemical interference in human serum.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical Engineering and Electronics Design Center, Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106, USA. cxh300@case.edu.

ABSTRACT
Aspartate aminotransaminase (AST) is a hepatocelluar enzyme released into the bloodstream when hepatic cells are damaged, resulting in elevated blood levels of AST. A single use, disposable biosensor prototype, composed of catalytic iridium nano-particles dispersed on carbon paste, was developed to detect enzymatically-produced H2O2 in AST-mediated reactions. This biosensor is capable of measuring AST levels in a phosphate buffer and undiluted human serum over the concentration range of 0 to 0.89 μg/mL AST concentration (corresponding to 0-250 UL-1 specific activity). The biosensor operates at relatively low oxidation potential (+0.3 volt (V) versus the printed Ag/AgCl), minimizing any potential chemical interference in human serum. The measurements of AST in human serum using the biosensor compared well with those measured by standard hospital spectrophotometric assays. This Ir-C biosensor may be useful for AST measurements in the clinical environment.

No MeSH data available.


Related in: MedlinePlus