Correlating molecule count and release kinetics with vesicular size using open carbon nanopipettes

Andrew G. Ewing, Keke Hu, Rui Jia, Amir Hatamie, Kim Long Le Vo, Michael V. Mirkin

Research output: Contribution to journalArticlepeer-review

14 Scopus citations


In this work, open carbon nanopipettes (CNPs) with radius between 50 and 600 nm were used to control translocation of different-sized vesicles through the pipette orifice followed by nanoelectrochemical analysis. Vesicle impact electrochemical cytometry (VIEC) was used to determine the number of catecholamine molecules expelled from single vesicles onto an inner-wall carbon surface, where the duration of transmitter release was quantified and correlated to the vesicle size all in the same nanotip. This in turn allowed us to both size and count molecules for vesicles in a living cell. Here, small and sharp open CNPs were employed to carry out intracellular VIEC with minimal invasion and high sensitivity. Our findings with VIEC reveal that the vesicular content increases with vesicle size. The release kinetics of vesicular transmitters and dense core size have the same relation with the vesicle size, implying that the vesicular dense core size determines the speed of each release event. This direct correlation unravels one of the complexities of exocytosis.

Original languageEnglish (US)
Pages (from-to)16910-16914
Number of pages5
JournalJournal of the American Chemical Society
Issue number40
StatePublished - Oct 7 2020

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry


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