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Development And Detection Application Of Microcantilever Array Biochemical Sensor

Posted on:2018-11-10Degree:DoctorType:Dissertation
Country:ChinaCandidate:G P ZhangFull Text:PDF
GTID:1318330518498169Subject:Solid mechanics
Abstract/Summary:PDF Full Text Request
Microcantilever biochemical sensor technology is a new analysis method integrating micro-electromechanical system, biochemistry and mechanics. Based on atomic force microscope technology, this sensor technology detects the biochemical reactions occurring on the cantilever surface by detecting the deflection signal of the cantilever in real time. This technology has the advantages of high sensitivity, label free,real time and in situ, and has extensive research and application prospects in biochemical analysis.In this dissertation, a microcantilever array sensor system was built to detect an array containing eight microcantilevers in real time based on the microcantilever sensor technology. It used optical fibers to guide lasers and achieved real-time detection of eight cantilevers by sequential control of lasers.This sensor system was aimed to eliminate temperature drift, signal noise and achieve high throughput detection.Multiple performance evaluation and optimization design were carried out on this sensor system. The noise was reduced and the detection sensitivity was improved effectively and the sensor system was more convenient to use. Microcystin LR was detected quantitatively by this sensor platform. The mail work of this dissertation is as follows:A microcantilever array sensor system was built by using optical fibers as the light source of microcantilever array. It could detect the deflection of microcantilever array containing eight cantilvers in real time. The overall structure of the system was introduced. The light path was optimized to reduce the influence of stray light effectively and align the lasers with cantilevers more conveniently. A liquid cell with reasonable structure and volume was designed and made. Microcantilever array chips fitting the system were made.The signal noise of the sensor system was analyzed and the influence of laser scanning period was studied too. Each laser was set to work at least 400ms in each scanning period. The consistent response of the sensor system was evaluated by comparing the temperature-rise response of cantilevers with a commercial microcantilever array. The relative deviation of the temperature sensitivities was less than 7.8%, showing good consistency. The copper ion and clenbuterol was detected quantitatively and result showed good consistency and reflected the contrast between test and reference cantilvers. The quantitative detection of mercury ion was carried out and the result was in good agreement with the same concentration. The lowest concentration of mercury ion detected in the test was 0.1ng/mL.The fabricated microcantilever array chip was tested used for detection. The radius of curvature of the cantilever is about 15mm, which can guarantee the requirement of cantilever flatness. In the temperature response test, the deflections of cantilever have a good linear relationship with the temperature with a fit coefficient of greater than 0.99,and the temperature response sensitivity relative deviation was no more than 5.0%,showing good consistency. This microcantilever array was used to detect mercury ions quantitatively and the detection results were compared with the results of the commercial microcantilever array. The fabricated cantilevers generated a deflection of 21.0nm under 1ng/mL of mercury ions, while the commercial cantilevers generated a deflection of 39.0nm under 0.2ng/mL of mercury ions. The results showed that the fabricated cantilever had higher stiffness and lower sensitivity.Microcystin LR was detected quantitatively by using aptamer modified microcantilever array in the sensor system. The detection range was 1-500ng/mL and the theoretical limit was 0.6ng/mL. This cantilever sensor based on the aptamer was able to identify microcystin LR in tap water and distinguish microcystin LR from the microcystin isomers.
Keywords/Search Tags:microcantilver array sensor, microcantilever array, biochemical sensor, heavy metal ions, microcystin LR
PDF Full Text Request
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