Surface potential microscopy of surfactant-controlled single gold nanoparticle

Hyungbeen Lee, Yoochan Hong, Dongtak Lee, Seungyeon Hwang, Gyudo Lee, Jaemoon Yang, Dae Sung Yoon

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


The surface potential of nanoparticles plays a key role in numerous applications, such as drug delivery and cellular uptake. The estimation of the surface potential of nanoparticles as drug carriers or contrast agents is important for the design of nanoparticle-based biomedical platforms. Herein, we report the direct measurement of the surface potential of individual gold nanorods (GNRs) via Kelvin probe force microscopy (KPFM) at the nanoscale. GNRs were capped by a surfactant, cetyltrimethylammonium bromide (CTAB), which was removed by centrifugation. CTAB removal is essential for GNR-based biomedical applications because of the cytotoxicity of CTAB. Applying KPFM analysis, we found that the mean surface potential of the GNRs became more negative as the CTAB was removed from the GNR. The results indicate that the negative charge of GNRs is covered by the electrostatic charge of the CTAB molecules. Similar trends were observed in experiments with gold nanospheres (GNS) capped by citrates. Overall, KPFM-based techniques characterize the surfactant of individual nanoparticles (i.e. GNR or GNS) with high resolution by mapping the surface potential of a single nanoparticle, which aids in designing engineered nanoparticles for biomedical applications.

Original languageEnglish
Article number215706
Issue number21
Publication statusPublished - 2020 May 22

Bibliographical note

Funding Information:
This work was supported by the National Research Foundation of Korea (NRF) Grant funded by the Korean Government (MSIP) (No., NRF-2017R1A6A3A11034311, NRF-2018M3 C1B7020722, and NRF-2019R1A2B5B01070617). Also, This work was supported by a grant of the Korea Health Technology RandD Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health and Welfare, Republic of Korea (HI16C0179 and HI17C2586)

Publisher Copyright:
© 2020 IOP Publishing Ltd.


  • Capping agent
  • Gold nanorod
  • Gold nanosphere
  • Kelvin probe force microscopy
  • Surface potential

ASJC Scopus subject areas

  • Bioengineering
  • General Chemistry
  • General Materials Science
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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