Community Research and Development Information Service - CORDIS

Microfluidics and sensor design

This module covered the design and development of the microfluidics system and the assembly of the multi-channel, automated TIRF-based immunosensor instrument. The unit was designed to be small enough to be carried to a test river site where it could be installed to provide continuous surveillance of pollution levels for up to 32 different chemical compounds.

The first stage in this process required agreement on the technical specification of the instrument and this involved extensive discussions between both ‘user’ and ‘supplier’ partners within the Consortium, concluding with the preparation of a technical specification manual, which defined the design parameters for the major components of the system.

The result of this collaboration was the fabrication, testing and development of a 32-channel analyser, consisting of integrated electronics, and optics and fluidic modules. The electronics modules consisted of pumps, valves, power and laser supplies housed in a metal casing. The metal casing provided Rf shielding for low noise linear amplification circuits that interfaced with a 32 photodiode array, which were housed in a separate light-tight metal compartment. The microfluidics component consisted of a PMMA embossed flow chamber, with a critical chamber dimension of approximately 35µm depth, covering an array of 32 sensor zones, each zone being 1.5mm long and 300µm wide, on a fibre pigtailed TIRF chip. Tests showed that the chamber structure maintained poiseuille fluid flow across the sensor region and it could therefore deliver binding assay results with good repeatability. The photodetection system consisted of an array of highly polished optical fibres in close contact with the sensor chip at one end and the photodiode array at the other. The amplified signals from the photodiodes were transmitted to the measurement control and data acquisition system through individually shielded outputs.

The analyser underwent a commissioning and bench testing regime by CRL, Southampton University, Siemens and Tuebingen University and the fully integrated instrument, including the computer interface and autosampler modules, will now be permanently attached to Tuebingen University, where it will continue to be tested and developed. A second instrument will undergo field testing by the other ‘user’ partners. Specification documentation and a summary operating instructions manual have been produced and supplied to the ‘users’. These documents are intended to support future opportunities to supply instruments to customers on a commercial basis.

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Eberhard-Karls-University of Tuebingen
Auf der Morgenstelle 8
72076 Tubingen
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