Layers of polymer foils with different properties and functions have been merged to integrate heating, microfluidics and DNA microarray technology into one device. DNA microarrays offer the possibility for massive parallel DNA analysis. Traditionally made on glass, they are however difficult to integrate in low-cost applications. Heat induced assays such as PCR and melting curve analysis are important diagnostic tools for the centralized lab, conventionally performed using benchtop laboratory equipment with precise temperature control. By using thin flexible polymer foil components, these powerful technologies can be integrated to make a standalone lab-on-a-chip device.
The heating system used here is based on a novel heating concept using a thin copper mesh film and has several advantages. The most important one is its homogenous heating characteristics, which is used for real time monitoring of denaturing DNA duplexes upon exposure to a thermal gradient, so called melting curve analysis. Polymer foils also has the advantage over materials such as glass and silicon, that foil-based systems can be manufactured using high-throughput roll-to-roll production, similar to technologies used in the paper industry, which can help in reducing manufacturing costs.
‘I think these diagnostic polymer foils are very interesting alternatives to standard DNA microarrays, especially when it comes to point of care diagnostics’, says Associate Professor Aman Russom, group leader of the Clinical Microfluidics group in the Nanobiotechnology laboratory at KTH. ‘Polymer foils can be produced at costs less than one US dollar and are not dependent on an external electricity source, other than a battery.’
Point of care diagnostics is defined as a simple and convenient medical test that can be brought to the patient. And this is exactly what you can do with this small plastic device that can be run on a 2V battery. There is however one more technical hurdle to overcome before this diagnostics can really be applied in the field.
‘We are working on how to integrate the sample preparation, the pre-amplification step, into the diagnostic device itself. In this proof of principle study we have been using a standard PCR machine, but this step could quite easily be integrated in the polymer foil’, says Aman Russom. Next step will also be to test this microarray chip in a clinically relevant question.’
Genotyping of Single Nucleotide Polymorphisms by melting curve analysis using thin film semi-transparent heaters integrated in a lab-on-foil system
Ohlander, A., Zilio, C., Hammerle, T., Zelenin, S., Klink, G., Chiari, M., Bock, K. and Russom, A.
Lab on a Chip, online 22 March 2013
The Science for Life Laboratory is a joint effort between four Swedish universities, Karolinska Institute, The Royal Institute of Technology (KTH), Stockholm University and Uppsala University. The centre combines advanced technology with a broad knowledge in translational medicine and molecular biosciences. SciLifeLab is a new national strategic investment in life science research that demands large-scale and specialized infrastructure. SciLifeLab has the goal to become one of the leading research centres in the world within the areas of Health and Environment.