Spatially Addressed Deposition and Imaging of Biochemically Active Bead Microstructures by Scanning Electrochemical Microscopy

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• 作者：C. Ajith Wijayawardhana ; Gunther Wittstock ; H. Brian Halsall ; and William R. Heineman
• 刊名：Analytical Chemistry
• 出版年：2000
• 出版时间：January 15, 2000
• 年：2000
• 卷：72
• 期：2
• 页码：333 - 338
• 全文大小：322K
• 年卷期：v.72,no.2(January 15, 2000)
• ISSN：1520-6882

文摘

A new procedure is described to deposit paramagneticbeads on surfaces to form microscopic agglomerates. Byusing surface-modified beads, microscopic structureswith defined biochemical activity are formed. The shapeand size of agglomerates were characterized by scanningelectron microscopy (SEM), and the biochemical activitywas mapped with scanning electrochemical microscopy(SECM). This approach is demonstrated using beadsmodified with anti-mouse antibodies (Ab). After allowingthem to react with a conjugate of mouse IgG and alkalinephosphatase (ALP), the beads were deposited as agglomerates of well-defined size and shape. The biochemical activity was recorded in the generation-collectionSECM mode by oxidizing 4-aminophenol formed in theALP-catalyzed hydrolysis of 4-aminophenyl phosphate atthe surface of the beads. The signal height correlated withboth the amount of beads present in one agglomerate andthe proportion of Ab binding sites saturated with theALP-mouse IgG conjugate. The feedback mode of theSECM was used to image streptavidin-coated beads afterreaction with biotinylated glucose oxidase.