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Article

Scanning Electrochemical Microscopy of Model Neurons: Imaging and Real-Time Detection of Morphological Changes

Johanna M. Liebetrau,^† Heather M. Miller,^‡ and John E. Baur*

Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160

Sara A. Takacs, Vipavee Anupunpisit,^§ and Paul A. Garris

Department of Biological Sciences, Illinois State University, Normal, Illinois 61790-4120

David O. Wipf

Department of Chemistry, Mississippi State University, Mississippi State, Mississippi, 39762

Anal. Chem., 2003, 75 (3), pp 563–571

DOI: 10.1021/ac026166v

Publication Date (Web): December 28, 2002

†

Current address: Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285.

‡

Current address: Department of Chemistry and Biochemistry, Northern Illinois University, DeKalb, IL 60115-2862.

Corresponding author. Fax: (309) 438-5538. E-mail: jebaur@ilstu.edu.

Visiting researcher from Anatomy Department, Faculty of Medicine, Srinakharinwirot University, Bankgok, Thailand.

Abstract

Living PC12 cells, a model cell type for studying neuronal function, were imaged using the negative feedback mode of a scanning electrochemical microscope (SECM). Six biocompatible redox mediators were successfully identified from a large pool of candidates and were then used for imaging PC12 cells before and after exposure to nerve growth factor (NGF). When exposed to NGF, cells differentiate into a neuron phenotype by growing narrow neurites (1−2 μm wide) that can extend >100 μm from the cell proper. We demonstrate that carbon fiber electrodes with reduced tip diameters can be used for imaging both the cell proper and these neurites. Regions of decreased current, possibly resulting from raised features not identifiable by light microscopy, are clearly evident in the SECM images. Changes in the morphology of undifferentiated PC12 cells could be detected in real time with the SECM. After exposure to hypotonic and hypertonic solutions, reversible changes in cell height of <2 μm were measured.

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