Fabrication and Prostate Specific Antigen Testing of a Piezoresistive Microcantilever Beam Biosensor
Date Issued
2007
Date
2007
Author(s)
Chiou, Yong-Shan
DOI
zh-TW
Abstract
Prostate cancer is becoming one of the top three major cancer killers for elderly men in the west, and it is also one of the ten major cancers reported of Taiwan in 2006. Prostate specific antigen (PSA) is found to be the most valuable tumor sign of prostate cancer. It has become the highest value of biomarkers in cancers. In this study, the piezoresistive microcantilever is required for operation in a phosphate buffered saline solution or human plasma which is to maintain a specific pH environment of a strong electrolyte. As a result, the device is required to be electrically insulated in solution environment. The selected silicon nitride is used to conform to the requirements for the insulting material. The cantilevers are designed in 150 or 200 μm long, 50 μm wide and about 1.4 μm thick. The integrated piezoresistive resistors are 100 μm long, 50 μm wide and 200 nm thick, and the expected resistance is approximately 4 kΩ. Meanwhile, the gold layer (30 nm thick) coated on the cantilever surface is necessary for chemical reaction of biolinker, and thus the sensing surface of specific protein adsorption and its associated recognition. In addition to the microcantilever device, several important issues need to be considered in height, length, width, and the total volume of the channel, as well as the flow field in the microchannel. In the micro-fluid system, the laminar flow is also required to reduce the noise from vibrations of the cantilever. The biosensor is wire bonded directly on the printed circuit board (PCB) with a height of 470μm, connected to the signal processing device on the PCB. Preliminary result of PSA detection was obtained by this piezoresistive microcantilever. The device is confirmed to be tested in solution environment and thus its preliminary feasibility. More testing is required for further verification in PSA detection.
Subjects
壓阻式微懸臂梁生物感測器
惠斯同電橋
前列腺特異抗原
離子濃度
Piezoresistive Microcantilever Beam Biosensor
Wheatstone bridge circuit
Prostate Specific Antigen
Ion concentration
SDGs
Type
thesis
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