Larsen, Simon Tylsgaard

Taboryski, Rafael J.

Tanzi, Simone

We present a novel method to fabricate an all in polymer injection molded chip for electrochemical cell recordings and lateral cell trapping. The complete device is molded in thermoplastic polymer and it results from assembling two halves. We tested spin-coated conductive polymer poly(3,4-ethylenedioxythiopene) and showed that it can be used as an electrode material for detecting neurotransmitters electrochemically in biosensors

Online Research Database In Technology

                       General rights Copyright and moral rights for the publications made accessible in the public portal are retained by the authors and/or other copyright owners and it is a condition of accessing publications that users recognise and abide by the legal requirements associated with these rights.  • Users may download and print one copy of any publication from the public portal for the purpose of private study or research. • You may not further distribute the material or use it for any profit-making activity or commercial gain • You may freely distribute the URL identifying the publication in the public portal   If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.     Downloaded from orbit.dtu.dk on: Dec 20, 2017Injection molded polymer chip for electrochemical and electrophysiological recordingsfrom single cellsTanzi, Simone; Larsen, Simon Tylsgaard; Taboryski, Rafael J.Publication date:2011Link back to DTU OrbitCitation (APA):Tanzi, S., Larsen, S. T., & Taboryski, R. J. (2011). Injection molded polymer chip for electrochemical andelectrophysiological recordings from single cells. Poster session presented at 37th International Conference onMicro and Nano Engineering, Berlin, Germany.Electrochemical recordingsOxidation of the neurotransmitter Dopamine was done with different concentrations using slow scan cyclic voltammetry. The scans show that dopamine is readily oxidized, although the oxidation potential seems to be slightly lower than on carbon and platinum electrodes. When PEDOT microelectrodes are used for low noise amperometric measurements, the noise depends on the area of the electrodes. By making the electrode surface sufficiently small, noise levels below 2 pA can be reached.Deep Reactive Ion Etch (DRIE) system. The process includes photolithography for master origination of fluidic channels, electroplating of Si-master for Ni shim fabrication, injection molding for replication of the master, plasma assisted thermal bonding of parts for assembling the chip [4]. Parts were injection molded from TOPAS Cyclic Olefin Copolymer (COC).Proof of conceptPolydimethylsiloxane (PDMS) replicas have been made from the Nickel shim in order to demonstrate the feasibility of the lateral cell trapping with the chosen geometry. Single polystyrene microbeads (10 µm diameter) have been trapped at the end of the channel by applying suction to the capillary.   We present a novel method to fabricate an all in polymer injection molded chip for electrochemical cell recordings and lateral cell trapping. The complete device is molded in thermoplastic polymer and it results from assembling two halves. We tested spin-coated conductive polymer poly(3,4-ethylenedioxythiopene) and showed that it can be used as an electrode material for detecting neurotransmitters electrochemically in biosensors.Device conceptThe chip design was inspired by the so-called mouse-hole configuration [1] where a hole through a fluidic compartment wall results from from assembling two halves; one half has an open channel structure and the other half has flat surface. This creates a microfluidic junction between a main chamber and a lateral recording capillary.MicrofabricationThe chips were fabricated using the UV-LIGA process [2,3],however here we used a Si master that was etched in aPolymer electrodesElectrodes to be used for electrochemical recordings were applied to the flat part of the TOPAS chip before bonding. Due to the relatively low melting temperature of the polymer substrate, electrode fabrication procedures that involve heating to high temperatures can not be used. Our electrodes are made of conducting polymer PEDOT which was spin-coated and patterned with standard photolithography. PEDOT microelectrodes with widths between 4 and 50 microns were fabricated and tested.Chip preparation, concept desing and test. (a) UV-LIGA process.  Photolithography and DRIE etching for Si master origination, Electroplating for Nichel shim fabrication and Injection molding for replication of the master.(b) Schematic of so-called mouse-hole configuration. (c) 10 µm diameter polystyrene bead patch on a test PDMS replica.SEM micrographs. (a) Si master, (b) Nickel insert for the injection molding machine, (c) injection molded polymer part.Injection molded polymer chip for electrochemical and electrophysiological recordings from single cellsSimone Tanzi*§, Simon T. Larsen*§, and Rafael Taboryski** DTU Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark ‡ The first two authors contributed equally to this studyReferences:[1] C. Ionescu-Zanettii et al. (2005) PNAS 102, 9112-9117[2] E. W. Becker et al. (1982) Naturwissenschaften 69, 520–3[3] V. Piotter et al. (1997) Microsyst. Technol. 3, 129–33 [4] R. Taboryski et al. (2010) J. Micromech. Microeng. 20, 055010Simone Tanzi simt@nanotech.dtu.dk Simon T. Larsen   sitl@nanotech.dtu.dk Rafael Taboryski   rata@nanotech.dtu.dkFigure 4: Cyclic voltammograms showing the oxidation of dopamine on a PEDOT electrode. Dopamine was diluted in PBS buffer. Scan rate: 10 mV/s, electrode dimensions: 50 µm X 1500 µm.. The large hysteresis is due to the high capacitance of PEDOTFigure 5: Noise versus electrode area. The noise was calculated as the root mean square noise of a current trace with the electrode being exposed to phosphate buffer. 3. Electroplating1. PhotolithographySi masterSi masterResistPolymer chipNi shimNi shim2. Etching (DRIE)4. Injection moldingCellThey show a high capacitance compared to other thin film electrodes of 1670+-130 µF/cm2, while the sheet resistance lies around 100 Ω.

Injection molded polymer chip for electrochemical and electrophysiological recordings from single cells

http://orbit.dtu.dk/ws/files/12141764/MNE%202011%20final.pdf

Injection molded polymer chip for electrochemical and electrophysiological recordings from single cells

Abstract

Similar works

Full text

Available Versions

Online Research Database In Technology