A reusable and specific protein A-coated piezoelectric biosensor for flow injection immunoassay

Hsin Chun Lu, Hsiu Mei Chen*, Yu Sheng Lin, Jeng Wei Lin

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

52 Scopus citations

Abstract

A hydrophilic matrix of periodate-oxidized dextran was used as a double-sided linker to covalently immobilize Staphylococcus aureus protein A (SpA) molecules onto a poly-L-lysine-modified piezoelectric crystal surface to improve their stability, activity, and binding specificity with human immunoglobulin G (IgG) in flow injection assays. The prepared sensing crystals displayed best sensitivity and reusability at a flow rate of 140 μL/min. A human IgG concentration as low as 0.3 nM can be detected by this system. Up to 19 successive assay repetitions were achieved without significant loss of sensitivity using the same crystal. The analysis of adsorption kinetics indicates that such a preparation can greatly increase the amount of available active human IgG binding sites on immobilized SpA. Hardly any response arising from unspecific binding was detected. In addition, the sensing crystal prepared by this method was found to retain activity better than one prepared via direct deposition when stored in either wet or dry states. Finally, the prepared SpA-coated crystals were applied to the affinity immobilization of polyclonal goat anti-Schistosoma japonicum glutathione-S-transferase (GST) and were able to subsequently detect GST and its genetically engineered mutant either in a purified form or in the crude cell lysate.

Original languageEnglish
Pages (from-to)116-124
Number of pages9
JournalBiotechnology Progress
Volume16
Issue number1
DOIs
StatePublished - 01 2000

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