Abstract

Liquid Crystals in Microfluidic Devices for Biosensing Applications

Kun-Lin Yang, Associate Professor,Department of Chemical and Biomolecular Engineering, National University of Singapore

Microfluidic sensors possess several advantages such as smaller sample volume, shorter assay time and lower cost compared to conventional assays performed in 96-well plates. However, because of its miniaturized format, microfluidic sensors also faced serious challenges in signal detection because of inherent short light path length, small sample volume, and short residence time. To overcome these limitations in microfluidic sensors, ultrasensitive signal detection and amplification mechanism are required. In this presentation, integration of liquid crystal (LC) materials with microfluidic devices for various chemical and biological sensing applications will be discussed. Because molecules form a LC phase have polar functional groups which have long-range interactions, they respond collectively to surface molecular binding events and change their orientations accordingly. This working principle has been exploited to develop highly sensitive biosensors in microfluidic devices. Using LC for signal transduction and amplification is advantageous because it is highly sensitive, fast and simple. More importantly, optical outputs of LC can be observed with the naked eye directly without using any complex instrumentation. Interference colors of LC also offer a simple way for qualitative and spatial analysis of protein concentration in microfluidic devices. Using LC-based microfluidic sensors, different biomolecules such as antibodies and enzymes can be detected in microfluidic devices.