Automated printing of electrochemical immunoassay microarrays: studies of conditions affecting alkaline phosphatase enzyme label activity

by Williams, Caitlin R.; Fritsch, Ingrid

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Microarray printing of components of an enzyme-linked immunosorbant assay (ELISA) is attractive for constructing miniaturized platforms to simultaneously and quant. analyze multiple chem. species in clin., environmental, and forensic applications. A truncated version of an electrochem. ELISA was used to address a major challenge of this approach, namely the effect of evapn. on assay activity. An antibody-alk. phosphatase conjugate (Ab-AP) was printed with a microarrayer onto an N-hydroxysuccinimide-ester-terminated self-assembled monolayer on gold. The activity of the enzyme label AP to convert the substrate p-aminophenyl phosphate to electroactive p-aminophenol was followed as a function of different conditions via detection by cyclic voltammetry at microband electrodes. It was found that enzyme activity decreased by 60% from 30 min to 4 h after evapn. However, printing in ambient humidity ("dry") as opposed to printing in a humidified chamber, resulted in the highest assay signals obsd. and low nonspecific adsorption.

Journal
ECS Transactions
Volume
28
Issue
21, Student Posters (General)--217th ECS Meeting, 2010
Year
2010
Start Page
19
ISBN/ISSN
1938-6737
DOI
10.1149/1.3496016