Fabrication and Photoresponse of Novel Carboxymethylcellulose (CMC) Based Bacteriorhodopsin (bR) Sensor

A single-pixel dry-type reconstituted bacteriorhodopsin (bR) sensor (Au/CMC + bR/ITO) incorporating carboxyrnethylcellulose (CMC) as the artificial membrane is fabricated according to a protocol developed to investigate signal acquisition from the proposed biosensor. Droplets of reconstituted purple membrane (PM) containing bR applied onto a gel-like solution of CMC placed on gold electrodes (anode) are allowed to dry under an electric field, utilising the PM fragment's net negative charge and electric dipole moment. The resulting bR matrix thin film with high molecular orientation is finally sandwiched together with a semi-transparent indium titanium oxide (ITO) counter electrode and proper electrical connections made to form a single pixel bR-CMC photosensor. Efficient and reproducible photoresponse observed upon illumination clearly exhibits the potential of the proposed biosensor for future photosensing works. (C) 2006 Elsevier B.V. All rights reserved

Occurrence of the" Peaking Effect" Corresponding to the" Highest Range of Effective Intensities" exhibited by Bacteriorhodopsin (bR)-Carboxymethylcellulose (CMC) Biosensor upon Illumination

Photo-electrical characterization works were carried out to understand the basic functionality of the novel bacteriorhodopsin (bR) - Carboxymethylcellulose (CMC) photosensor proposed and fabricated earlier. A single-pixel sensor was fabricated and its photoresponse towards light intensities and thermal variations studied. The occurrence of the "peaking effect" corresponding to a certain "highest range of effective intensities" upon light illumination was also observed and discussed

Capillary force assisted fabrication of DNA templated silver wires

We demonstrate for the first time the formation of micron scale conductive silver (Ag) wires induced by capillary forces through scribed micro-cuts on a deoxyribonucleic acid-silver nanoparticle (DNA-AgNPs) film. The "writing" flexibility based on the physical re-arrangement of the particles may prove to be prominent towards the fabrication of conductive wires

Field emission from nanometer-scale tips of crystalline PbZr x

The authors report field emission from nanometer-sharp tips of polarized PbZrxTi1-xO3 (PZT), silicon, and platinum. The PZT nanoemitters are fabricated in a batch fabrication process from single-crystal silicon tips that are coated with a 30 nm thick film of crystalline PZT. The nanoemitters start to emit electrons at fields as low as 2 V/μm and reach threshold emission, or turn-on, at fields as low as 3.9 V/μm. The turn-on field is 3.9 V/μm for PbZr0.2Ti 0.8O3, 6.8 V/μm for PbZr0.52Ti 0.48O3, and 10.75 V/μm for PbZr0.8Ti 0.2O3. The silicon nanoemitters have an electron emission turn-on field of 7.2 V/μm, and the platinum nanoemitters have an electron emission turn-on field of 5.75 V/μm. Using a Fowler-Nordheim analysis, the calculated effective work function of the PbZr0.2Ti 0.8O3 film is 1.00 eV, and the field amplification factor is ∼1526. © 2013 American Vacuum Society

Ruthenium oxide/tungsten oxide composite nanofibers as anode catalysts for the green energy generation of Chlorella vulgaris mediated biophotovoltaic cells

The development of electrochemically active and stable anode catalysts for the photoelectrochemical splitting of water molecules via biophotovoltaic cells (BPVs) utilizing microalgae receives a prime importance in green energy sector. Herein, we report the ruthenium oxide (RuO2)/tungsten oxide (WO3) composite nanofibers based photoanode for the application of high performance and durable BPV. The sequential arrangement of 6 nm sized RuO2/WO3 spherical particles constitutes the nanofibrous morphology and a number of surface active sites and structural integrity of nanofibers demonstrate the excellent and stable photo-oxidation currents. Under the light regime, RuO2/WO3/carbon cloth photoanode exhibits the substantial BPV power and current densities with an excellent durability. Thus this systematic study evokes the fundamental understanding on the electron generation and transference mechanisms, which offers new dimensions in the development of high performance and durable BPVs. © 2019 American Institute of Chemical Engineer

A simple, portable, electrochemical biosensor to screen shellfish for vibrio parahaemolyticus

An earlier electrochemical mechanism of DNA detection was adapted and specified for the detection of Vibrio parahaemolyticus in real samples. The reader, based on a screen printed carbon electrode, was modified with polylactide-stabilized gold nanoparticles and methylene blue was employed as the redox indicator. Detection was assessed using a microprocessor to measure current response under controlled potential. The fabricated sensor was able to specifically distinguish complementary, non-complementary and mismatched oligonucleotides. DNA was measured in the range of 2.0 × 10−8–2.0 × 10−13 M with a detection limit of 2.16 pM. The relative standard deviation for 6 replications of differential pulse voltammetry (DPV) measurement of 0.2 µM complementary DNA was 4.33%. Additionally, cross-reactivity studies against various other food-borne pathogens showed a reliably sensitive detection of the target pathogen. Successful identification of Vibrio parahaemolyticus (spiked and unspiked) in fresh cockles, combined with its simplicity and portability demonstrate the potential of the device as a practical screening tool