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Vimala Juliet, A.
- Synthesis and Characterization of Silver Nanoparticles from Escherichia coli MTCC 118
Authors
1 Department of Electronics and Control Engg., Sathyabama University, Chennai, IN
2 Department of Instrumentation and Control Engg., SRM University, Chennai, IN
Source
Biometrics and Bioinformatics, Vol 4, No 1 (2012), Pagination: 9-12Abstract
This paper aims to report the synthesis and characterization of silver nanoparticles using the extract of Escherichia coli MTCC 118. The cell extract from this new strain is used for the first time for the synthesis of silver nanoparticles. This method of synthesis is a biological synthesis method by adding silver nitrate into the cell extract. This method is nontoxic, low cost and energy efficient compared to physical and chemical procedures [1]. Using the biological method, silver ions are bioreduced into silver nanoparticles from the cell extract of Escherichia coli MTCC 118. The formation of silver nanoparticles was then confirmed by indication of change in colour from colourless to reddish brown. This colour change was observed using UV-Vis Spectroscopy. UV-Visible spectrum of the aqueous medium containing silver ions was observed at the peak at 440-445nm corresponding to the surface plasmon absorbance of silver nanoparticles. The silver nanoparticles thus formed were further analyzed and characterized by FTIR (Fourier Transform Infrared Spectroscopy), XRD (X-ray Diffraction Analysis) and AFM (Atomic force Microscopy). The average diameter of the silver nanoparticles was found to be in the range of 93-170nm using AFM. Samples given for further characterization of size and morphology of silver nanoparticles using TEM (Transmission Electron Microscopy) and SEM (Scanning Electron Microscopy). Further the synthesized silver nanoparticles were tested against common bacterial pathogens. These biosynthesized silver nanoparticles may be used to develop a biosensor model for the detection of bacteria [2].
Keywords
Silver Nanoparticles, UV-Vis Spectroscopy, FTIR (Fourier Transform Infrared Spectroscopy), XRD (X-Ray Diffraction Analysis) and AFM (Atomic Force Microscopy), TEM (Transmission Electron Microscopy) and SEM (Scanning Electron Microscopy).
- Design and Simulation of PolySi Diaphragm Capacitive Pressure Sensor
Authors
1 Department of Instrumentation & Control Engineering, SRM University, Tamilnadu, IN
2 Department of Instrumentation & Control Engineering, SRM University, Tamilnadu, IN
Source
Biometrics and Bioinformatics, Vol 2, No 3 (2010), Pagination: 53-55Abstract
This paper presents the design and simulation of a capacitive pressure sensor system for industrial and biomedical applications. Employing the Micro Electro Mechanical Systems (MEMS) technology, high sensor sensitivities and resolutions have been achieved. This report provides initial data on the design and simulation of such a sensor. The sensor is composed of a polysilicon diaphragm that deflects due to pressure applied over it. Applied pressure deflects the 2 µm diaphragm changing the capacitance between the Silicon substrate and the polysilicon diaphragm. The pressure sensor provides a linear change in capacitance versus pressure in the range of 0.1MPa to 1MPa. The simulation result shows a displacement of 0.25µm / 0.1MPa of the diaphragm and capacitance of 30fF to 44fF in the linear region.