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 journalArticle

Abstract

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
JournalNanotechnology
Volume31
Issue number21
DOIs
Publication statusPublished - 2020 May 22

Keywords

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

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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