A new fabrication process could make it easier and less expensive to incorporate optical sensing onto lab-on-a-chip devices. These devices integrate laboratory functions onto a plastic or glass "chip" typically no more than a few square centimeters in size, allowing automated testing in the doctor's office or various types of chemical or biological analysis with portable instruments.
The most common material used to make lab-on-a-chip devices today is the silicone poly-dimethylsiloxane (PDMS) because of its optical, mechanical and chemical properties, its low cost and the ease at which it can be structured at the microscale. As these devices become more common and increasingly complex, there is a need for less expensive ways to incorporate all-PDMS optical components such as waveguides to direct light onto and within the chip.
"Our new method is compatible with the development of lab-on-chip platforms where integrated optical waveguides can be a great tool for light-based diagnostics or monitoring applications," said Mathieu Hautefeuille of Universidad National Autonomous University of Mexico, co-author of the paper.
In the journal Optical Materials Express
, from The Optical Society (OSA), the researchers describe their simple and inexpensive method for making PDMS waveguides that can be easily integrated into a lab-on-a-chip device made of the same material. They use their new approach to fabricate a PDMS beam splitter, which splits laser output into two beams.
"To the best of our knowledge, this is the first time that low-power laser etching has been used to microstructure polymers for optical waveguide fabrication," said Hautefeuille. "This study shows that a very inexpensive laser platform, based on a CD/DVD unit in our case, can compete with high-power lasers for such applications."
The researchers say that their new fabrication technique could be useful for other applications, including those requiring precision microstructuring, and that it can be used to etch other polymer materials in addition to PDMS.