{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T21:16:14Z","timestamp":1760217374270,"version":"build-2065373602"},"reference-count":36,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2015,1,6]],"date-time":"2015-01-06T00:00:00Z","timestamp":1420502400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Vesicular exocytosis is ubiquitous, but it is difficult to detect within the cells\u2019 communication mechanism. For this purpose, a 2 \u00b5m ultramicrodic carbon fiber electrode was fabricated in this work based on electrodeposition with over-oxidized polypyrrole nanoparticle (PPyox-CFE), which was applied successfully for real-time monitoring of quantal exocytosis from individual pheochromocytoma (PC12) cells. PPyox-CFE was evaluated by dopamine (DA) solutions through cyclic voltammetry and amperometry electrochemical methods, and results revealed that PPyox-CFE improved the detection limit of DA. In particular, the sensitivity of DA was improved to 24.55 \u00b5A\u00b7\u00b5M\u22121\u00b7\u00b5m\u22122 using the PPyox-CFE. The ultramicrodic electrode combined with the patch-clamp system was used to detect vesicular exocytosis of DA from individual PC12 cells with 60 mM K+ stimulation. A total of 287 spikes released from 7 PC12 cells were statistically analyzed. The current amplitude (Imax) and the released charge (Q) of the amperometric spikes from the DA release by a stimulated PC12 cell is 45.1 \u00b1 12.5 pA and 0.18 \u00b1 0.04 pC, respectively. Furthermore, on average ~562,000 molecules were released in each vesicular exocytosis. PPyox-CFE, with its capability of detecting vesicular exocytosis, has potential application in neuron communication research.<\/jats:p>","DOI":"10.3390\/s150100868","type":"journal-article","created":{"date-parts":[[2015,1,6]],"date-time":"2015-01-06T09:11:06Z","timestamp":1420535466000},"page":"868-879","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Carbon Fiber Ultramicrodic Electrode Electrodeposited with Over-Oxidized Polypyrrole for Amperometric Detection of Vesicular Exocytosis from Pheochromocytoma Cell"],"prefix":"10.3390","volume":"15","author":[{"given":"Li","family":"Wang","sequence":"first","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Electronics Chinese Academy of Sciences, Beijing 100190, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Huiren","family":"Xu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Electronics Chinese Academy of Sciences, Beijing 100190, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Yilin","family":"Song","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Electronics Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jinping","family":"Luo","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Electronics Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Shengwei","family":"Xu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Electronics Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Song","family":"Zhang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Electronics Chinese Academy of Sciences, Beijing 100190, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Juntao","family":"Liu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Electronics Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5997-7252","authenticated-orcid":false,"given":"Xinxia","family":"Cai","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Transducer Technology, Institute of Electronics Chinese Academy of Sciences, Beijing 100190, China"},{"name":"University of Chinese Academy of Sciences, Beijing 100190, China"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2015,1,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1038\/newbio234181a0","article-title":"Spontaneous and evoked quantal transmitter release at a vertebrate central synapse","volume":"234","author":"Albert","year":"1971","journal-title":"Nat. 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