The goal of this project is the development of a scalable n x n electrochemical detector array platform with on- chip amplifiers for massively parallel recordings of quantal transmitter release events. The neurobiological process that this assay will analyze is the process of exocytosis and transmitter release, one of the key processes in brain function and beyond. The molecules to be released are stored at high concentration in membrane-bound organelles. Upon stimulation the contents of these vesicles are released in quantal events through a fusion pore that connects the vesicular lumen to the extracellular space. Understanding the mechanisms of vesicle fusion and transmitter release is of broad medical significance. In the treatment of Parkinson's disease the drug levodopa increases dopamine release from the reduced number of dopaminergic neurons. On the other hand, BoTox treatment exerts its effect through the reduction of transmitter release. In addition to these examples, many other drugs and many molecular manipulations modulate transmitter release in various ways. This regulation of transmitter release occurs not only via changing the number or frequency of quantal release events but also via modulation of quantal size and of the kinetics of release from individual vesicles. To understand the mechanism by which a specific manipulation affects transmitter release it is therefore necessary to perform precise measurements of individual quantal release events, analyze their amplitude and time course and derive characteristic parameters. Conventionally, such measurements are performed by positioning a carbon fiber microelectrode close to a cell (such as a chromaffin cell, a dopaminergic or serotonergic neuron or a PC12 cell) under microscopic observation, stimulate the cell and record a series of release events. The technology developed in this project is adapted from the semiconductor industry and involves the development of a CMOS microelectronic chip for on-chip recordings of single quantal release events of oxidizable transmitter molecules such as noradrenaline, dopamine, or serotonin. The technology will allow the simultaneous recording of single vesicle release events from hundreds of cells without the need for microscopic observation and manipulation, and will thereby provide a high-throughput platform to characterize molecular and pharmacological manipulations. The technology will accelerate the research aimed at understanding the molecular mechanisms of transmitter release and its modulation as well as the development and testing of treatments that act through the modulation of transmitter release. In this way this novel assay platform would provide opportunities to measure quantal release events as neurobiological endpoints and will provide a pipeline for target identification and drug discovery.
Release of neurotransmitters and hormones is regulated by many proteins, signaling molecules and various drugs. Two examples are the drug L-Dopa, used to treat Parkinson's disease, or the cosmetic BoTox treatment. The goal of this project is the development of a scalable n x n electrochemical detector array platform with on-chip amplifiers for massively parallel recordings of individual transmitter release events. This novel assay platform will provide opportunities to measure quantal release events as neurobiological endpoints and will provide a pipeline for target identification and drug discovery.
|Gillis, Kevin D; Liu, Xin A; Marcantoni, Andrea et al. (2018) Electrochemical measurement of quantal exocytosis using microchips. Pflugers Arch 470:97-112|
|Huang, Meng; Delacruz, Joannalyn B; Ruelas, John C et al. (2018) Surface-modified CMOS IC electrochemical sensor array targeting single chromaffin cells for highly parallel amperometry measurements. Pflugers Arch 470:113-123|
|Dorta-Quinones, Carlos I; Huang, Meng; Ruelas, John C et al. (2018) A Bidirectional-Current CMOS Potentiostat for Fast-Scan Cyclic Voltammetry Detector Arrays. IEEE Trans Biomed Circuits Syst 12:894-903|
|Balaji Ramachandran, Supriya; Gillis, Kevin D (2018) A matched-filter algorithm to detect amperometric spikes resulting from quantal secretion. J Neurosci Methods 293:338-346|
|Dorta-Quiñones, Carlos I; Wang, Xiao Y; Dokania, Rajeev K et al. (2016) A Wireless FSCV Monitoring IC With Analog Background Subtraction and UWB Telemetry. IEEE Trans Biomed Circuits Syst 10:289-99|
|Sharma, Satyan; Lindau, Manfred (2016) The mystery of the fusion pore. Nat Struct Mol Biol 23:5-6|
|Yao, J; Liu, X A; Gillis, K D (2015) Two approaches for addressing electrochemical electrode arrays with reduced external connections. Anal Methods 7:5760-5766|
|Sharma, Satyan; Kim, Brian N; Stansfeld, Phillip J et al. (2015) A Coarse Grained Model for a Lipid Membrane with Physiological Composition and Leaflet Asymmetry. PLoS One 10:e0144814|
|Jayant, Krishna; Singhai, Amit; Cao, Yingqiu et al. (2015) Non-Faradaic Electrochemical Detection of Exocytosis from Mast and Chromaffin Cells Using Floating-Gate MOS Transistors. Sci Rep 5:18477|
|Gao, Changlu; Sun, Xiuhua; Gillis, Kevin D (2013) Fabrication of two-layer poly(dimethyl siloxane) devices for hydrodynamic cell trapping and exocytosis measurement with integrated indium tin oxide microelectrodes arrays. Biomed Microdevices 15:445-51|
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