Using a flexible silicone material, engineers from University of California—Santa Cruz built an integrated optofluidic platform for biological sample processing and optical analysis. The optofluidic platform features tunable optics and novel "lightvalves."

The new device is made entirely of polydimethylsiloxane (PDMS), a soft material used in microfluidics and products such as contact lenses and medical devices.

The flexibility of PDMS allows for novel ways of controlling both light and fluids on the chip. By employing multilayer soft lithography techniques, senior graduate student Joshua Parks built chips containing both solid-core and hollow-core waveguides for directing light signals, as well as fluidic microvalves to control the movement of liquid samples. Additionally, a special microvalve functions as a "lightvalve," controlling the flow of both light and fluids.

"We can use this fabrication method now to build an all-in-one device that allows us to do biological sample processing and optical detection on one chip," said electrical engineer Holger Schmidt, the Kapany Professor of Optoelectronics and director of the W. M. Keck Center for Nanoscale Optofluidics at UC Santa Cruz.

The potential applications for the technology include a wide range of biological sensors and analytical devices. With viral diagnostic assays, for example, fluorescently labeled antibodies can tag specific viral strains for optical detection.