title: A microfluidic method for dopamine uptake measurements in dopaminergic neurons.
abstract: Dopamine (DA) is a classical neurotransmitter and dysfunction in its synaptic handling underlies many neurological disorders, including addiction, depression, and neurodegeneration. A key to understanding DA dysfunction is the accurate measurement of dopamine uptake by dopaminergic neurons. Current methods that allow for the analysis of dopamine uptake rely on standard multiwell-plate based ELISA, or on carbon-fibre microelectrodes used in in vivo recording techniques. The former suffers from challenges associated with automation and analyte degradation, while the latter has low throughput and is not ideal for laboratory screening. In response to these challenges, we introduce a digital microfluidic platform to evaluate dopamine homeostasis in in vitro neuron culture. The method features voltammetric dopamine sensors with limit of detection of 30 nM integrated with cell culture sites for multi-day neuron culture and differentiation. We demonstrate the utility of the new technique for DA uptake assays featuring in-line culture and analysis, with a determination of uptake of approximately ∼32 fmol in 10 min per virtual microwell (each containing ∼200 differentiated SH-SY5Y cells). We propose that future generations of this technique will be useful for drug discovery for neurodegenerative disease as well as for a wide range of applications that would benefit from integrated cell culture and electroanalysis.
authors.affiliation: Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College St, Toronto, ON M5s 3G9, Canada. aaron.wheeler@utoronto.ca and Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1, Canada.
authors.forename: Yue
authors.initials: Y
authors.lastname: Yu
authors.affiliation: Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1, Canada and Department of Chemistry, University of Toronto, 80 St Georg St., Toronto, ON M5S 3H6, Canada.
authors.forename: Mohtashim H
authors.initials: MH
authors.lastname: Shamsi
authors.affiliation: Department of Human Biology, University of Toronto, 300 Huron Street, Toronto, ON M5S 3J6, Canada.
authors.forename: Dimitar L
authors.initials: DL
authors.lastname: Krastev
authors.affiliation: Department of Chemistry, University of Toronto, 80 St Georg St., Toronto, ON M5S 3H6, Canada.
authors.forename: Michael D M
authors.initials: MD
authors.lastname: Dryden
authors.affiliation: Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1, Canada.
authors.forename: Yen
authors.initials: Y
authors.lastname: Leung
authors.affiliation: Institute for Biomaterials and Biomedical Engineering, University of Toronto, 164 College St, Toronto, ON M5s 3G9, Canada. aaron.wheeler@utoronto.ca and Donnelly Centre for Cellular and Biomolecular Research, 160 College St., Toronto, ON M5S 3E1, Canada.
authors.forename: Aaron R
authors.initials: AR
authors.lastname: Wheeler
mesh_terms: D018929:Cell Culture Techniques / Q000295:instrumentation / Q000379:methods; D045744:Cell Line, Tumor; D004298:Dopamine / Q000378:metabolism*; D059290:Dopaminergic Neurons / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods*
chemical_list: D004298:Dopamine