Liquid Crystal Bio-Sensor
Crystal Diagnostics has harnessed the power of liquid crystal technology to create the world’s first liquid crystal bio-sensor. This technology uses the unique optical characteristics of liquid crystals to permit rapid, selective, and easy to use detection of dangerous microbes.
The liquid crystals are elongated crystalline structures suspended in water and can be aligned in a BioCassette consisting of two parallel glass sheets with specially prepared interior surfaces. When liquid crystal flows into the BioCassette, the crystalline structures interact with the proprietarily treated glass surface to align in a constant direction. Within the CDx Reader, polarizing filters are above and below the BioCassette; one oriented parallel with the aligned matrix, the other oriented perpendicular to the aligned matrix.
When the BioCassette is trans-illuminated with light from below, only light waves oriented in the same direction as the polarizer and matrix can cross and reach the top of the CDx Reader chamber (where five 14MP cameras are located). However, because the second polarizer is oriented 90 degrees out of phase with the transmitted light waves, no light can cross the polarizor. Therefore, no detectable signal is created.
Creating a Target
Specific antibodies or other selective binding agents (such as aptamers) are used to identify the microbe of interest. The selected antibody binds only to a molecule expressed on the surface of a specific microbe species. When this interaction occurs, the antibody causes the formation of microbe aggregates. The aggregates distort the aligned liquid crystal matrix once they exceed a critical diameter (3-5 microns).
The distorted matrix causes bending of the light so that some waves are reoriented to align with the second polarizer. Because light aligned with the second polarizer can cross that polarizer, a detectable spot of light is imaged (each spot represents a target aggregate). The formation of aggregates and the resulting distortion of the liquid crystal matrix allow light transmission to occur rapidly. Each matrix distortion permits transmission of trans-illuminating polarized light to create a detectable signal that represents a positive microbe detection.