{"id":59,"date":"2010-08-23T13:42:12","date_gmt":"2010-08-23T20:42:12","guid":{"rendered":"http:\/\/www.deepspace.ucsb.edu\/wordpress\/?page_id=59"},"modified":"2010-08-24T17:36:14","modified_gmt":"2010-08-25T00:36:14","slug":"edna","status":"publish","type":"page","link":"http:\/\/128.111.23.62\/wordpress\/projects\/small-projects\/edna","title":{"rendered":"eDNA"},"content":{"rendered":"
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eDNA (Click for larger image)<\/p><\/div>\n

The eDNA project was a collabrative effort between the Plaxco Chemistry Group and the Lubin expermental Astrophysics to make a low noise potentiastat. \u00a0The purpose of the project was to design a fast, low noise multi channel poteniastat, using an FPGA to read multiple channels simultaneously and\u00a0perform digital signal processing (DSP) on the board.\u00a0 Previous to this the Chemistry department used a multiplexing potentiastat to read multiple channels.\u00a0<\/p>\n

The application\u00a0for the board was both general electro-chemistry and the eventual compression into a hand held device for multi target aptamer bio sensing.\u00a0 The eventual goal was to have close to one hundred targets on a\u00a0single test chip, to allow for testing\u00a0of various biological substances.\u00a0 Aptamers were successful in testing for DNA fragments, large and some small molecules;\u00a0H1N1\u00a0bird flu DNA fragments, various proteins and Cocaine were all detected.\u00a0 The cocaine sensor was able to react\u00a0quickly to concentration\u00a0and could detect the change in concentration over the course of a few minutes.<\/p>\n

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eDNA Analog Front End<\/p><\/div>\n

To get a low noise, a large linear power supply was used, which made the device table bound.\u00a0 The eventual use of\u00a0a battery was planned\u00a0however this\u00a0was not implemented in the\u00a0latest version.\u00a0 The speed was about\u00a0four times faster than that of the multiplexing potentiastat and read the channels simultaneously.\u00a0 The data was processed in the FPGA, using logical phase sensitive demodulators,\u00a0called lock-ins.\u00a0 The processed data was structured and passed to a computer program where it could be visualized.\u00a0 The system unfortunately was wired with specific voltage and current specifications and was not easy to change for varying sized electrodes.\u00a0\u00a0 A further design that would implement an auto ranging system, was proposed but never implemented.\u00a0 After this, the project ended and the Chemistry department found an off the shelf device to meet their needs.<\/p>\n