Bioimmunoassay based on hydrophobin HGFI self-assembled whispering gallery mode optofluidic microresonator

A bioimmunoassay method based on hydrophobin HGFI self-assembled whispering gallery mode (WGM) optofluidic microresonator has been proposed and experimentally demonstrated. Exeprimental results indicate that with the unique feature of hydrophobin protein, a tightly stable protein membrane can effectively form on the inner surface of the WGM microresonator through self-assembly. Owing to high surface activity of the nanoscale hydrophobin protein film, it could change the polar nature of the modified microresonator surface, and helps to the adsorption of biomolecules. Spectral characteristics of the WGM resonance dips have been investigated to evaluate the dynamic process for the immunodetection. The WGM transmission spectrum shows a regular shift with the increment of observation time, which could be exploited for analysis of the immunodetection process. The proposed bioimmunoassay method has several advantages such as low cost, simple fabrication, label-free and miniature, which could find promising applications in biochemical and biomedical detection fields. (C) 2021 Elsevier B.V. All rights reserved.