PEG Functionalization of Whispering Gallery Mode Optical Microresonator Biosensors to Minimize Non-Specific Adsorption during Targeted, Label-Free Sensing

Sensors

Fanyongjing Wang¹  Mark Anderson²  Matthew T. Bernards³  Heather K. Hunt¹ 

[1] Department of Bioengineering, University of Missouri, Columbia, MO 65201, USA; E-Mail:;Department of Biochemistry, University of Missouri, Columbia, MO 65201, USA; E-Mail:;Department of Chemical Engineering, University of Missouri, Columbia, MO 65201, USA; E-Mail:

关键词: optical microresonator;    surface functionalization;    non-specific adsorption;    surface characterization;    PEG;    nonfouling surfaces;   

DOI  :  10.3390/s150818040

来源: mdpi

【 摘 要 】

Whispering Gallery Mode (WGM) optical microresonator biosensors are a powerful tool for targeted detection of analytes at extremely low concentrations. However, in complex environments, non-specific adsorption can significantly reduce their signal to noise ratio, limiting their accuracy. To overcome this, poly(ethylene glycol) (PEG) can be employed in conjunction with appropriate recognition elements to create a nonfouling surface capable of detecting targeted analytes. This paper investigates a general route for the addition of nonfouling elements to WGM optical biosensors to reduce non-specific adsorption, while also retaining high sensitivity. We use the avidin-biotin analyte-recognition element system, in conjunction with PEG nonfouling elements, as a proof-of-concept, and explore the extent of non-specific adsorption of lysozyme and fibrinogen at multiple concentrations, as well as the ability to detect avidin in a concentration-dependent fashion. Ellipsometry, contact angle measurement, fluorescence microscopy, and optical resonator characterization methods were used to study non-specific adsorption, the quality of the functionalized surface, and the biosensor’s performance. Using a recognition element ratio to nonfouling element ratio of 1:1, we showed that non-specific adsorption could be significantly reduced over the controls, and that high sensitivity could be maintained. Due to the frequent use of biotin-avidin-biotin sandwich complexes in functionalizing sensor surfaces with biotin-labeled recognition elements, this chemistry could provide a common basis for creating a non-fouling surface capable of targeted detection. This should improve the ability of WGM optical biosensors to operate in complex environments, extending their application towards real-world detection.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.