The technology of microfluidics has the potential to revolutionize the way in which a wide range of analytical and diagnostic tests are implemented in... Microfluidics - Layout - Fixtures - Chip scale packaging - Communities - Software - Materials - microfluidics - prototypes - carrier platform - microfluidics - CMC microsystems - platform modules - prototyping environment
A Carrier Platform for Microfluidics Research and Prototyping R. E. Mallard CMC Microsystems Kingston, Ontario, K7L 3N6, Canada Abstract- The technology of microfluidics has the potential to revolutionize the way in which a wide range of analytical and diagnostic tests are implemented in applications ranging from genomics to healthcare to environmental monitoring. The translation of innovation in microfluidic devices developed through academic research into actual applications is greatly facilitated by the availability of a prototyping platform, through which a proof-of-concept microsystem can be rapidly and efficiently prototyped. We present a description of a platform developed by CMC Microsystems and its academic research partners for the development of microsystem prototypes employing microfluidic technology. Implementing such a platform in a modular configuration is one means of addressing the diversity of functional requirements driven by the wide range of microfluidic research interests. The challenge of the developing such a platform is strongly concerned with defining not only a physical layout, but also the interfacial standards between the platform modules. The prototyping environment we describe is termed a “Carrier Platform” as it provides a standard for carrying the various microfluidic devices and signals which comprise the system function.
I. INTRODUCTION CMC Microsystems, in collaboration with its partners in Canadian academia, has developed a “Carrier Platform” for microfluidics research and system-level prototyping. The aim of the platform development project is to provide a set of hardware, software drivers, chip layouts and fabrication services which provides a standard for microsystem prototyping. The platform has been described as a carrier, in that its primary functional goals are to provide a standard physical interface to a microfluidic device as well as a means of mediating the various fluidic, electrical and optical stimuli which are required for the implementation of the microfluidic technology in a system level application. This initiative is one of several undertaken by CMC, a not-for-profit corporation managing a major grant from the Natural Sciences and Engineering Research Council of Canada, in order to support the Canadian academic community engaged in microsystems research [1, 2]. Fundamentally, the platform aims to deliver a technology evaluation and development tool which allows this community to rapidly and efficiently implement their microfluidic technology in a proof of concept prototyping environment. The platform provides the standard modular functional blocks of such a system and defines standard interfaces between these
blocks. Researchers who adopt this interface standard have turn-key access to a generic microfluidic technology characterization tool environment. II. PROJECT DESCRIPTION Part of CMC Microsystems’ role, is to provide researchers with industry-calibre design resources, access to state-of-the-art prototyping technologies, tools for test and support services, to accelerate Canadian competitiveness through microsystems. The products and services that CMC delivers involve multiple technology domains, including microelectronics, photonics, MEMS, and microfluidics. Given its mandate, the needs of the academic research community have strongly influenced the direction which the CMC Carrier Platform development project has taken. In order to define the set of required core platform functionalities, as well as to collect advice on preferred platform architectures and microfluidic “best practices”, a team of 12 academic advisors and beta testers was assembled from 9 universities across the country. The research interests of this group included such diverse topics as electrophoretic transport, bio-materials detection and analysis, biomedical device development, micro-robotics and microelectronic system modeling. The Carrier Platform concept is to deliver an adaptable hardware and SW environment which addresses the research needs of this group, for the implementation of first functional system prototypes employing novel microfluidic technology. This differentiates the platform vision from that which is intended for exploratory materials research. Neither is the Carrier Platform implemented in a product-ready, commercializable footprint, which might narrow the application focus of the platform and constrain its applicability to a diverse research community. III.PLATFORM MODULARITY The system functions addressing the varying needs of the beta test group were the basis for defining the target core functionality of the platform. A modular architecture was proposed, offering considerable flexibility to the individual researcher for the adoption of functional elements appropriate to specific needs, whilst allowing them to adapt and refine select elements specific to their field of interest. The platform depicted in figure 1 contains six modules: 1. Microfluidic fixture, which holds a user-defined microfluidic chip, and defines the electrical and fluidic connections on and off that chip
2. 3. 4.
Microfluidic chip fabrication services Microfluidic interface, including fluidic pumping, containment, valving, flow and pressure sensing Data input/output and driver module, which electrically interfaces the fixture to the chip. It provides applicationsspecific functionality such as amplification and function generation, as driven by typical microfluidic technologies such as electrophoresis or analogue electrical sensing Optical analysis functionality, comprising drivers for video analysis of fluidic motion or state, as well as visible wavelength range laser induced fluorescence analysis Configurable microsystem core, based on an FPGA development environment. This module may function either as a system level backbone to manage all system functionality, or as a fast, real time data co-processor.
1/16” outside diameter. Components conforming to these specifications and addressing a wide range of microfluidic application requirements are readily available as off the shelf commercial products. In cases where a commercial offering was not available, or where a component cost reduction or functional optimization was desired, CMC has engineered custom components to meet the platform requirement. This includes the platform fixture itself, as well as a dedicated 4 channel arbitrary function generator/amplifier for electrophoretic applications.
Figure 2. Fixture and Microfluidic Interface Component Set Figure 1. Platform Modular Architecture First and foremost, the platform includes links to microfluidic chip fabrication services. While there is a range of materials systems and fluidic chip designs of research interest, the current default fabrication service supported by CMC supports channel microfluidics fabricated in glass. This includes provision for the layout of in-channel electrode structures, which can be configured towards electrophorectic or sensing applications or as simple interconnects for the integration of microelectronic passive or active components. Secondly, a fluidic interface to the chip is provided. The platform fixture’s function is to carry the electrical signals and fluidic media on and off of the chip. The platform imposes little constraint over the layout of the microfluidic channels or on-chip electrode structures, although the fixture design does define the layout of the fluidic ports and chip pin-outs so that fluidic and electrical continuity to the chip is assured. Users who wish to implement alternate microchip materials or fabrication services can still adopt the platform by ensuring that their chip design conforms to the layout of these input/output ports; engineering drawings describing these locations and tolerances are available through CMC. IV. IMPLEMENTATION In order to ensure “plumbing compatibility” between the range of components supported by the platform, CMC has standardized on fluidic tubing which has either a 360Pm or
The main microfluidic interface components are pictured in figure 2. Of note are the syringe pump, in-line flow meter, pressure gauge, adapter fittings, fixture, and electrical cables. A baseplate and screw mounts are provided to secure these components, as required. All of the interface components may be addressed through a host computer, and regulated using a software interface written in Labview. This basic software allows a user to regulate and monitor the fluidic flow rate. CMC encourages feedback and increased uptake of the Carrier Platform. Researchers interested in further information should consult CMC’s website, at www.cmc.ca.
ACKNOWLEDGEMENT CMC wishes to thank the team advisors for their guidance in the specification of the platform. In particular, this includes Drs Paul Charette, Colin Dalton, Bonnie Gray, Doug Thomson, John Yeow and Sylvan Martel, from the universities of Sherbrooke, Calgary, Simon Fraser, Manitoba and Waterloo and École Polytechnqiue de Montréal, respectively. The project was supported through the contributions of the Natural Sciences and Engineering Research Council and the Canada Foundation for Innovation. REFERENCES  Bernard Courtois, Benoît Charlot, Gregory Di Pendina, and Libor Rufer, “Infrastructures for Education, Research and Industry: CMOS and MEMS for BioMed”, Proc IMS3TW, Vancouver, June 2008, in press  H Pollitt-Smith and S Xu, "FPGAs in Microsystems Education", Proceedings of the European Workshop on Microelectronics Education (EWME), Kluwer Academic Publishers, 2004.