Lee, Hyungbeen Hong, Yoochan Lee, Dongtak Hwang, Seungyeon Lee, Gyudo Yang, Jaemoon Yoon, Dae Sung 2024-01-19T17:33:06Z 2024-01-19T17:33:06Z 2022-01-25 2020-05 0957-4484 https://pubs.kist.re.kr/handle/201004/118650 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. English IOP PUBLISHING LTD Surface potential microscopy of surfactant-controlled single gold nanoparticle Article 10.1088/1361-6528/ab73b7 1 NANOTECHNOLOGY, v.31, no.21 NANOTECHNOLOGY 31 21 N scie scopus 000519067500001 2-s2.0-85081945919 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Physics, Applied Science & Technology - Other Topics Materials Science Physics Article PROBE FORCE MICROSCOPY AGGREGATION RESOLUTION NANORODS LEVEL gold nanorod gold nanosphere capping agent surface potential Kelvin probe force microscopy