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Design And Application Of Microcantilever Array Biochemical Sensor

Posted on:2013-09-09Degree:DoctorType:Dissertation
Country:ChinaCandidate:L WuFull Text:PDF
GTID:1228330377951852Subject:Solid mechanics
Abstract/Summary:PDF Full Text Request
Microcantilever biochemical sensing technology are developed based on the Micro Electro Mechanical Systems and atomic force microscopy, and have the advantages of high sensitivity, lable-free, in-situ reproduction of biochemical reaction information, etc. In addition, its detection principle is as following:when the biochemical reactions occur on the microcantilever unilateral surface, the surface stress will change, which makes the microcantilever bend. Then we can obtain the information of the biochemical reactions by detecting the microcantilever deflection with optical lever methods.To eliminate the impact of environmental noise such as temperature drift and change of liquid refractive index in the microcantilever biochemical sensing system and achieve high-throughput detection, we improved the single microcantilever biochemical detection system and did an in-depth study on the microcantilever array biochemical sensing technology, and presented several feasible programs for detection of microcantilever array signals. After a preliminary experimental verification, we designed a stable and reliable microcantilever array biochemical sensing system, which can be used in the actual biochemical detection. Meanwhile, considering the sensitivity of bi-material microcantilever to the changes of ambient temperature, we manufactured a high sensitive microcantilever temperature sensor. The main work is as follows:The performance of the two different detection principles of position sensitive detectors used in experiments were analysed, and the impact of the shape and size of the laser spot and the stray light to the detection sensitivity of the system was discussed. In addition, the optical structure of the system was improved, and using the baffle to eliminate the stray light, the detection sensitivity of the system was effectively increased.The designed structure of the biochemical reaction cell was improve, which reduced the volume of the cell, and can effectively remove the bubbles in the cavity. Meanwhile,the new retractable structure design made the internal lug boss for placing microcantilever exposed in an open environment, which facilitated the adjusting and fixing of the microcantilever.Aiming at the characteristic of bi-material microcantilever being sensitive to the changes of ambient temperature, a high sensitive microcantilever temperature sensor was manufactured, which has a good linearity and repeatability. With a commercial microcantilever as the temperature sensing element, whose dimensions are length200μm, width40μm,0.6μm thickness of silicon nitride, and0.06μm thickness of gold, the temperature resolution of the sensor was tested to be0.02K. If the microcantilever parameters were further optimized, the temperature resolution of the sensor could be0.1mK.Six feasible ways for microcantilever array detection were presented, and preliminary experimental tests were done:(1)Use the expanded surface light source to illuminate the microcantilever array, and then receive the light spots reflected by microcantilever array with CCD for imaging detection;(2) Use multiple lasers to illuminate the microcantilever array in sequence for detection;(3) Use the high luminous efficiency, small volume and light weight, low-cost fiber array to replace multiple lasers to illuminate the microcantilever array in sequence for detection;(4) According to the principle of acousto-optic modulation, drive a single laser beam by controlling the acoustic frequency signals to scan microcantilever array for detection;(5) use the digital micromirror device as light switch to reflect the corresponding light onto the microcantilever array in sequence for detection;(6) Based on the piezoelectric scan principle, drive a single laser beam by controlling the input voltage of piezoelectric ceramic tube to scan microcantilever array for detection.A capillary array modification device for modifying different biochemical molecules onto each beam of the microcantilever array was designed. And by further improving and enhancing the performance of the microcantilever array sensing system based on piezoelectric scanning, an initial microcantilever array biochemical sensor which could be used in actual biochemical detection was constructed. On this basis, clenbuterol antibody was successfully immobilized on one beam (detecting beam) of the commercial microcantilever array, which has two beams, and the other one without modification was set to be reference beam. Finally,10μg/L clenbuterol antigen was accurately detected, which verified the practical feasibility of the microcantilever array sensor for biochemical detection.
Keywords/Search Tags:Microcantilever, Optical lever, Biochemical sensor, Temperature sensor, Micro Electro Mechanical Systems, Microcantilever array, Capillary array
PDF Full Text Request
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