Damage-free remote SF6 plasma-treated CNTs for facile fabrication of electrochemical enzyme biosensors

Sujin Kim, Dongryul Lee, Kyungmin Ahn, Jihyun Kim, Jungbae Kim

Research output: Contribution to journalArticlepeer-review

Abstract

Remote SF6 plasma treatment of CNTs is performed to graft hydrophobic fluorine on the surface of CNTs. Fluorinated CNTs (F-CNTs) allow for the facile adsorption of enzyme molecules via hydrophobic interaction between F-CNTs and the hydrophobic patches of enzyme molecules. The loading of glucose oxidase (GOx) on F-CNTs correlates well with plasma treatment time. Interestingly, the Rct value of GOx/F-CNTs decreases when CNTs are treated with plasma for a short time such as 1 and 5 min, which is due to weakly-bound chemisorbed fluorine molecules on F-CNTs (semi-ionic C-F). As an example, the Rct value of GOx/F-CNT electrode with 1 min plasma treatment is 0.57 times lower than that of GOx/CNTs, while increasing its sensitivity by 2.5 times. Upon extending the treatment time such as 30, 45 and 60 min, the XPS results reveal the dominance of covalently-attached fluorine, leading to marginally-increased resistance and sensitivity. It is worthy of noting this work is the first report of simple enzyme adsorption on remote-plasma treated CNT surfaces together with its detailed mechanism studies, especially for the binding of enzyme molecules semi-ionic fluorine.

Original languageEnglish
Article number157386
JournalApplied Surface Science
Volume628
DOIs
Publication statusPublished - 2023 Aug 15

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2020R1A2C3009649). This research was also supported by the K-Sensor Development Program (RS-2022-00154729) funded by the Ministry of Trade, Industry and Energy (MOTIE, Korea). We thank Dr. Youngho Wee for his advices during the revision process.

Publisher Copyright:
© 2023

Keywords

  • Carbon nanotubes
  • Enzyme adsorption
  • Enzyme biosensors
  • Remote plasma treatment

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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