Abstract
We have reported the in situ surface–enhanced Raman spectroscopy (SERS) monitoring of repetitive surface plasmon–mediated chemical transformation cycles in a conjugate nanobiological system. The nanobiological conjugate comprised a gold-coated plasmonic substrate biofunctionalized with thiolated single–stranded DNA carrying a reduction-oxidation indicator methylthioninium chloride, which is also known as methylene blue (MB), in buffer solution at a neutral pH. Exposure to a 523-nm laser excitation produced pronounced SERS bands of oxidized MB. Continued exposure to the laser resulted in disappearance of the SERS bands, which can be interpreted as a reduction of MB. This occurred in the absence of electrochemical stimulation, chemical agents, or catalysts, suggesting a surface plasmon–mediated mechanism of the transformation. The oxidized form of MB was recovered by an addition of fresh buffer solution on the surface of the sample. Continued laser exposure with periodical addition of the buffer resulted in repetitive cycles of changes in the SERS pattern, which were monitored in situ. The chemical transformations of MB were preceded by a buildup of an intermediate SERS pattern, which was attributed to a transient form of MB created by selective surface plasmon-driven excitation.
Department(s)
Physics, Astronomy, and Materials Science
Document Type
Article
DOI
https://doi.org/10.1007/s11468-019-01050-4
Rights Information
© 2020 by the authors. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http:// creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Keywords
Methylene blue, Nanobiological conjugates, Nanoplasmonics, Plasmon-driven photochemical reactions, SERS
Publication Date
4-1-2020
Recommended Citation
Shattique, Muhammad R., and Maria Stepanova. "Surface Plasmon-Driven Reversible Transformation of DNA-Bound Methylene Blue Detected In Situ by SERS." Plasmonics 15, no. 2 (2020): 427-434.
Journal Title
Plasmonics
