Date: Dec 15, 2008 Author: Joan Zimmermann Source: MDA (
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by Joan Zimmermann/jzimmermann@nttc.edu
Imagine going to your neighborhood drugstore and choosing from Aisle 4 a diagnostic kit that can test for high cholesterol, for a faulty gene that predisposes you to diabetes, or for a staph infection.
Examples of products etched using Translume's laser process.
The automation and miniaturization of laboratory functions have undergone a steady evolution of tweaks and improvements. These changes have enabled researchers to dig more deeply into biology, shorten assay times for pharmaceutical testing, and even take some items from the inner sanctum of the doctor's office to the open shelves of the drugstore. Translume is the latest contributor to the field, bringing both improved materials and manufacturing to microfluidic chips for biological and chemical testing. Such chips contain tiny channels that route reagents and reactants in sequence, replacing the researcher mixing chemicals at the bench for needs as diverse as antibody testing and DNA hybridization.
The technology has some tangled technological roots in MDA history. Translume (Ann Arbor, MI), with the help of a 2004 Phase I STTR from MDA, investigated the use of femtosecond lasers for maskless etching of glass materials and micromachining of optical structures. Philippe Bado, chief technical officer for Translume, also worked for Clark-MXR, Inc. (Ann Arbor, MI), another company that received MDA SBIR support in the early 1990s for the development of femtosecond lasers, which also are being used by Translume to carve channels in its new chip offerings.
Once upon a time, labs on chips were simple wells in which nanoliters to microliters of sample were used to carry out various reactions of interest. Today's more sophisticated chips use microfluidic channels, which with their very small dimensions add some advantages to the dynamics of chemical reactions, by adding what is essentially a plumbing system to route and direct reactants. As labs on a chip become more accepted in the consumer market and physicians let go of the diagnostic monopoly, pharmacies and other stores could sell inexpensive test kits to consumers. Quicker time to diagnosis also would be welcomed by physicians and patients alike.
Most commercial microfluidic chips are wet-etched in silicon (chemically), a method that results in trapezoidal or rectangular cross-sections with large rounded corners. These shapes are not suited to the chemistry desired by its users. Translume addresses these shortcomings with its direct laser-etching methods that produce deep channels with nearly vertical walls. In addition, Translume's chips are made of fused silicate, making them ideal for tests like fluorescence in situ hybridization (FISH), in which fluorescent markers are used to mark genes on stretches of DNA. Many materials possess natural fluorescence, or fluoresce in response to ultraviolet (UV) light, creating false signals. Fused silica does not auto-fluoresce and is transparent to UV. Its additional advantages are longevity and ruggedness, and it lasts well beyond the lifetime of the experimenter (centuries). The material has a hardness of 6.5 on the Mohs scale, slightly below that of quartz, and is thus highly resistant to scratches, making it ideal for robotic applications, in which the chips are handled repeatedly by not-so-gentle mechanics, or for the dirtier conditions of field work.
Translume has developed four femtosecond-laser-based fabrication processes to fabricate and commercialize fused silica devices, including its microfluidic chips: femtoTrim™, femtoWeld™, femtoEtch™, and femtoWrite™. The company uses the femtoWrite process to produce deep three-dimensional microchannels with sharp-shaped features that are unavailable using traditional mask and etching techniques. The reactions as conducted in these chips are roughly 10 times faster than "conventional" lab-on-a-chip offerings, owing to factors such as small reaction volumes and the relative distances traveled by the reagents as they travel through the microfluidic channels. The combination of the laser technology, robust materials, and Translume's efficient manufacturing approach allow the company to offer the new chips at a cost advantage.
The company also plans an expansion of this line to include micro-reactors, flow cytometers, and capillary electropheresis modules, which are used in the pharmaceutical and biotech industries.
The process of developing three-dimensional glass microstructures is termed GMEMS™ (Glass Micro Electro Mechanical Systems). The technology is useful in many other areas, such as the creation of micron-scale optical waveguides that can move or flex. Thus, Translume has much to offer in the optical communications area, as well as general manufacturing of materials requiring precision etching or drilling.
Translume continues to work with the Michigan Economic Development Corporation to further develop its market. In addition, the company is using some of its original venture- capital funding to improve its production line.
