科研之友
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摘要
Signal amplification in a surface acoustic wave (SAW) immunosensor is demonstrated by increasing mass and/or viscoelasticity on a delay line sensing surface with gold nanoparticles (AuNPs) for monitoring of airborne house dust mite (HDM) allergens. Streptavidin conjugated AuNPs with size of 20 nm are affinity bound to biotinylated detection antibodies (dAb) that are already on the sensor surface together with capture antibody (cAb) and group 1 HDM allergens of Dermatophagoides farinae (Der f 1) as a result of a sandwich assay. This immunocomplex except for immobilized cAb on the sensor surface is then removed by pH change for regeneration of the surface. Surface modification of the SAW immunosensor with a self-assembled monolayer of pH resistant protein (ORLA85 protein) allows to repeat a process including immunoassay and surface regeneration for a repetitive measurement of Der f 1. It is revealed that capping a surface of AuNP with a monolayer of (11-mercaptoundecyl)tri(ethylene glycol) (3PEG-thiol) reduces non-specific binding to the sensor surface, and aggregation among AuNPs. The sensor output is amplified by a factor of 3 with respect to that obtained without AuNP when a molar concentration of AuNPs is about 3-fold higher than that of dAb. A limit of detection for Der f 1 is 2.5 ng/mL (equivalent to 100 pM), which is about 2.5-fold improvement from the sandwich assay without AuNPs. Also highly reproducible sensor outputs along with efficient regeneration through successive measurement demonstrates the capability of repetitive measurement of Der f 1. These results suggest that use of AuNPs under an optimum condition in the SAW immunosensor is expected to realize a sensitive and repetitive measurement of HDM allergens, which is useful for airborne HDM monitoring system.
- 出版日期2017-10
