{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,23]],"date-time":"2026-10-23T01:58:12Z","timestamp":1792720692843,"version":"4.5.0"},"reference-count":42,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2015,7,24]],"date-time":"2015-07-24T00:00:00Z","timestamp":1437696000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>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\u2019s 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.<\/jats:p>","DOI":"10.3390\/s150818040","type":"journal-article","created":{"date-parts":[[2015,7,24]],"date-time":"2015-07-24T10:44:26Z","timestamp":1437734666000},"page":"18040-18060","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":38,"title":["PEG Functionalization of Whispering Gallery Mode Optical Microresonator Biosensors to Minimize Non-Specific Adsorption during Targeted, Label-Free Sensing"],"prefix":"10.3390","volume":"15","author":[{"given":"Fanyongjing","family":"Wang","sequence":"first","affiliation":[{"name":"Department of Bioengineering, University of Missouri, Columbia, MO 65201, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mark","family":"Anderson","sequence":"additional","affiliation":[{"name":"Department of Biochemistry, University of Missouri, Columbia, MO 65201, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthew","family":"Bernards","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, University of Missouri, Columbia, MO 65201, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Heather","family":"Hunt","sequence":"additional","affiliation":[{"name":"Department of Bioengineering, University of Missouri, Columbia, MO 65201, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2015,7,24]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"8","DOI":"10.1016\/j.aca.2008.05.022","article-title":"Sensitive optical biosensors for unlabeled targets: A review","volume":"620","author":"Fan","year":"2008","journal-title":"Anal. 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