Investigation of Charged Small Molecule−Aptamer Interactions with Surface Plasmon Resonance

Clarice E. Froehlich, Jiayi He, Christy L. Haynes

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


Investigating the interactions between small, charged molecules and aptamers using surface plasmon resonance (SPR) is limited by the inherent low response of small molecules and difficulties with nonspecific electrostatic interactions between the aptamer, analyte, and sensor surface. However, aptamers are increasingly being used in sensors for small molecule detection in critical areas like healthcare and environmental safety. The ability to probe these interactions through simple, direct SPR assays would be greatly beneficial and allow for the development of improved sensors without the need for complicated signal enhancement. However, these assays are nearly nonexistent in the current literature and are instead surpassed by sandwich or competitive binding techniques, which require additional sample preparation and reagents. In this work, we develop a method to characterize the interaction between the charged small molecule serotonin (176 Da) and an aptamer with SPR using streptavidin−biotin capture and a high-ionic-strength buffer. Additionally, other methods, such as serotonin immobilization and thiol-coupling of the aptamer, were investigated for comparison. These techniques give insight into working with small molecules and allow for quickly adapting a binding affinity assay into a direct SPR sensor.

Original languageEnglish (US)
Pages (from-to)2639-2644
Number of pages6
JournalAnalytical Chemistry
Issue number5
StatePublished - Feb 7 2023

Bibliographical note

Funding Information:
The authors would like to thank Kaitlyn Gruber and Casey Wouters for helpful discussions and assistance with running assays, and Casey Wouters and Beza Tuga for review of the manuscript, as well as Dr. Kevin Dorfman, Dr. C. Daniel Frisbie, and Demetra Adrahtas for support of the project. The S200 SPR instrument is supported with S10 Shared Instrument Grant 1S10OD021539-01 funded by the Office of Research Infrastructure Programs (ORIP)/NIH. Financial support for this work was provided primarily by the National Science Foundation through the University of Minnesota MRSEC under Award Number DMR-2011401.

Publisher Copyright:
© 2023 American Chemical Society.

MRSEC Support

  • Primary

PubMed: MeSH publication types

  • Journal Article
  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.


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