Plasma etched polymer microelectrochemical systems

Abstract

This paper presents a novel technique based on plasma etching for the mass production of polymer microchip devices. The method consists of the patterning of a photo-resist by a high resolution printer on a foil composed of three layers (5 microm copper/50 microm polyimide/5 microm copper). After this step, both copper layers are chemically etched in order to serve as a contact mask on the polyimide surface so as to produce the desired microstructure pattern. The foil is placed into a reactive plasma chamber in order to etch the exposed polyimide by means of an oxidizing plasma. The method enables holes, lines or larger areas to be etched, thereby generating either microholes, microchannels or electrodes in the plastic material. The copper can then be chemically removed or further patterned to produce conductive pads which are further electroplated with gold. The microchannel is then covered with a polyethylene terephthalate/polyethylene (PET/PE) lamination. The strength of this technology is that access holes for the fluid inlet and outlet, as well as gold coated electrodes can be fabricated without post-processing in a batch process. Demonstration of the application of such microelectrochemical systems is shown here by voltammetric detection inside a 60 nL microchannel, which presents the special feature of linear depletion of the analytes in the direction parallel to the microchannel.

The role of copper in cysteine oxidation: study of intra- and inter-molecular reactions in mass spectrometry

“…38,39 A reservoir of polycarbonate (ø = 6.5 mm, h = 5 mm) was glued at the inlet of the microchannel. The sample was loaded (V = 100 mL) in the reservoir in which a metallic electrode was immersed.…”

About the Electrospray Ionization Source in Mass Spectrometry: Electrochemistry and On-chip Reactions

“…[12] It consists of a single microchannel polyimide microchip developed by DiagnoSwiss SA (Monthey, Switzerland). [15,19] A reservoir of polycarbonate was glued at the inlet of the microchannel. Samples in 50/50 (v/v) MeOH/H 2 O were loaded in the reservoir in which an electrode was immersed to apply the high voltage with respect to the mass spectrometer.…”

“…[13,14] For instance, polyimide or polyethyleneterphthalate (PET) microchips can be used as emitters for ESI-MS. [15][16][17][18] The desired microchannels can be drilled by using a UV excimer laser ablating a PET substrate [16] or by plasma etching polyimide. [19] Dayon and coworkers used this microsprayer to selectively mark cysteines in peptides with different hydroquinones by on-line electrochemicaltagging. [20,21] The goal here is to add function to ESI (functional ESI -FESI) by taking advantage of the electrochemical aspects and of the source design in the particular case of bioinorganic studies (Fig.…”

Electrochemical generation of Cu(I) complexes in aqueous solutions studied by on-line mass spectrometry

“…It consists of a single microchannel (45 lm · 120 lm · 1 cm) polyimide microchip developed by DiagnoSwiss SA (Monthey, Switzerland) [17,18]. A reservoir of polycarbonate (/ = 6.5 mm, h = 5 mm) was fixed at the inlet of the microchannel.…”

“…In the present work, we used electrospray microchips [17,18] where the electrode was made of copper, etching away during the electrospray. 8-hydroxyquinoline (Hox) and bathocuproine (BCP), specific ligands for Cu 2+ and Cu + (Scheme 1), respectively, were electrosprayed with a sacrificial copper electrode.…”