Ultrasensitive Biosensing on the Zepto-Molar Level

Detection of analytes on the zepto-molar (10^-^2^1M) level has been achieved using a field-effect bio-detector. By applying a gating voltage to enzymes immobilized on the working electrode of the detector, amplification of the biocatalytic current was observed. The amplification is attributed to the modification of the tunnel barrier between the enzyme and the electrode by the gating voltage-induced electric field which exists at the solution-electrode interface. The detection was demonstrated with the glucose oxidase (GOx)-glucose and alcohol dehydrogenase (ADH)-ethanol biocatalytic systems. Glucose at zepto-molar level was detected with zepto-molar detection resolution. Equivalently, 30 glucose molecules present in the sample were detected and the detection system responded distinctively to the incremental change in the number of glucose molecules in unit of 30 molecules. The enzyme\u27s biospecificity was also preserved in the presence of the applied field. We present possible processes that could give rise to the electrical charges required to produce the observed current level

Ultrasensitive Biosensing on the Zepto-Molar Level

Detection of analytes on the zepto-molar (10^-^2^1M) level has been achieved using a field-effect bio-detector. By applying a gating voltage to enzymes immobilized on the working electrode of the detector, amplification of the biocatalytic current was observed. The amplification is attributed to the modification of the tunnel barrier between the enzyme and the electrode by the gating voltage-induced electric field which exists at the solution-electrode interface. The detection was demonstrated with the glucose oxidase (GOx)-glucose and alcohol dehydrogenase (ADH)-ethanol biocatalytic systems. Glucose at zepto-molar level was detected with zepto-molar detection resolution. Equivalently, 30 glucose molecules present in the sample were detected and the detection system responded distinctively to the incremental change in the number of glucose molecules in unit of 30 molecules. The enzyme\u27s biospecificity was also preserved in the presence of the applied field. We present possible processes that could give rise to the electrical charges required to produce the observed current level

A Hybrid Biofuel Cell Based on Electrooxidation of Glucose Using Ultra-Small Silicon Nanoparticles

The ultra-small silicon nanoparticle was shown to be an electrocatalyst for the electrooxidation of glucose. The oxidation appeared to be a first order reaction which involves the transfer of 1 electron. The oxidation potential showed a low onset of −0.4V vs. Ag/AgCl (−0.62V vs. RHE). The particle was used as the anode catalyst of a prototype hybrid biofuel cell, which operated on glucose and hydrogen peroxide. The output power of the hybrid cell showed a dependence on the enzymes used as the cathode catalyst. The power density was optimized to 3.7μW/cm2 when horseradish peroxidase was replaced by microperoxidase-11 (MP-11). Comparing the output power of the hybrid cell to that of a biofuel cell indicates enhanced cell performance due to the fast reaction kinetics of the particle. The long-term stability of the hybrid cell was characterized by monitoring the cell voltage for 5 days. It appeared to that the robustness of the silicon particle resulted in more cell stability compared to the long-term performance of a biofuel cell

A Hybrid Biofuel Cell Based on Electrooxidation of Glucose Using Ultra-Small Silicon Nanoparticles

The ultra-small silicon nanoparticle was shown to be an electrocatalyst for the electrooxidation of glucose. The oxidation appeared to be a first order reaction which involves the transfer of 1 electron. The oxidation potential showed a low onset of −0.4V vs. Ag/AgCl (−0.62V vs. RHE). The particle was used as the anode catalyst of a prototype hybrid biofuel cell, which operated on glucose and hydrogen peroxide. The output power of the hybrid cell showed a dependence on the enzymes used as the cathode catalyst. The power density was optimized to 3.7μW/cm2 when horseradish peroxidase was replaced by microperoxidase-11 (MP-11). Comparing the output power of the hybrid cell to that of a biofuel cell indicates enhanced cell performance due to the fast reaction kinetics of the particle. The long-term stability of the hybrid cell was characterized by monitoring the cell voltage for 5 days. It appeared to that the robustness of the silicon particle resulted in more cell stability compared to the long-term performance of a biofuel cell

Semiconducting Metal Oxide Based Sensors for Selective Gas Pollutant Detection

A review of some papers published in the last fifty years that focus on the semiconducting metal oxide (SMO) based sensors for the selective and sensitive detection of various environmental pollutants is presented