ACT/SGER: Liquid Crystal Materials for Biosensor Development

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This project combines liquid crystal (LC) physics and a concept of highly selective antibody-antigen binding as an underlying principle for development of a broad class of sensors capable of rapid (minutes) and accurate identification, detection and source location of microbial pathogens. The detecting and amplifying medium is a special class of materials referred to as lyotropic chromonic liquid crystals (LCLCs). Small and isolated bacteria, viruses and their antibodies cause no macroscopic distortions of the LCLC uniformly aligned in a flat cassette. However, distortions of the liquid crystal bulk orientation occur immediately once the immune complex formed via specific antibody-antigen binding reaches a critical size of the order of few microns. Water-based LCLCs are less harmful to bacteria then their regular thermotropic counterparts. The distortions of orientation are easily detectable by optical means. The research will advance the field of liquid crystals by introducing this new area of applications and the field of biosensing by adding a new sensing medium. The research will be conducted at the Liquid Crystal Institute, the world leader in liquid crystal science and technology, in collaboration with the Departments of Biological Sciences and Chemical Physics and will support training of students from the two different disciplines in cutting-edge research techniques of great value to national security.%%%Currently available tests of the presence of harmful microbes such as anthrax require a lengthy evaluation period of up to two days. This project aims for the development of a new class of microbial sensors capable of fast (minutes) and accurate detection. The novelty is in an elegant fusion of the unique properties of liquid crystals (similar to the materials used in displays and flat-panel TVs) and high selectivity of biological interactions based on antibody-antigen binding. When an antibody binds to an antigen of the targeted microbe, the reaction produces an enlarged "immune complex." This immune complex distorts the surrounding liquid crystal. The distortion can be detected optically, as it acts similarly to the "pixels" in liquid crystal displays and TVs. The difference is that the sensing medium is composed of liquid crystals based on water solutions that do not harm the bacteria being examined. The research will be conducted at the Liquid Crystal Institute, which is a world leader in liquid crystal science and technology, in collaboration with the Departments of Biological Sciences and Chemical Physics, and will support training of students from the two different disciplines in cutting-edge research techniques of great value to national security.