14 TECHNOLOGY Nanyang Technological University The specialty fibre research team assessing optical fibres used to create the fibre labs A lab in a fibre detects the binding of two molecules in solution. The ability Researchers in Singapore have developed fibre-based to detect such biological interactions in small volumes of “optofluidic” sensors for measuring the properties of tiny fluid could be important for life science research and amounts of fluid. The innovation increases the sensitivity medical diagnosis. of measurements and makes it less expensive for Their latest work improves on the previous technology, researchers and clinicians to study the properties of in which fluid was added to channels that run along the fluids. fibre. In the new approach, the researchers add The technology uses a photonic crystal fibre fluid to a transverse microchannel that is (PCF) – an optical fibre in which air channels The new design drilled through the PCF and crosses its core. surround a central core along which light This maximises the interaction between the passes. These air channels allow the integration is highly sensitive to light and the fluid. of elements that provide the fibre with additional The new design is highly sensitive to properties. Such elements often include changes in the changes in the refraction of light. In addition, it microelectronics and semiconductors. Now, a is easier to clean fluid from the new transverse collaborative group of researchers from refraction of light. channel than from channels that run along the Nanyang Technology University (NTU) and the fibre, making it easier to reuse the device. A*STAR (Agency for Science, Technology, and Research) The researchers now aim to improve the technology Institute for Infocomm Research (I2R) has focused on further by incorporating optical antennae, which will developing microfluidic devices in which the air channels further increase its sensitivity to changes in light. are filled with fluid. Fluid properties can be measured by analysing the extent to which light changes direction – or refracts – when For further information contact: it passes through the fluid. By filling the channels in PCFs Professor Perry Shum with fluid, scientists can use the light in the fibre to School of Electrical and Electronic Engineering measure the properties of this fluid. PCF channels are so Nanyang Technology University, Singapore small that just trillionths of a millilitre are needed. E-mail: epshum@ntu.edu.sg The NTU and I2R team previously used this approach to develop a temperature sensor. The researchers filled one Dr Dora Hu channel with a rod-like liquid crystal, which changes its Institute for Infocomm Research Agency for Science, Technology and Research, properties when heated. The resulting changes in the Singapore refraction of light passing through it can be measured to E-mail: jjhu@i2r.a-star.edu.sg determine the temperature. They have also developed a biological sensor that “ ”
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