A liquid crystal biosensor for specific detection of antigens

Highlight
• This paper demonstrates specific detection of a serum antigen using nematic liquid crystal.
• The liquid crystal-water interface did not respond to negative control antigens, but clearly did so to positive control antigens.
• This same mechanism could be employed to make prefabricated sensors specifically sensitive to virtually any other antigen.
• The potential of such a sensor is significant: a response can be rapidly visualized with only a few required components.

Following the principle of the enzyme-linked immunosorbent assay (ELISA) pathogen detection method, we demonstrate specific sensing of goat Immunoglobulin G (IgG) by a nematic liquid crystal material. Sensing occurs via the visually-striking realignment of a pre-fabricated liquid crystal film, suspended in grids and coated with biotinylated lipids followed by biotinylated anti-goat IgG. Realignment occurs when the targeted goat IgG is added to the cell, but not when rat or rabbit serum IgG is added to the same surface. In principle, this method can be generalized to provide an inexpensive, fast and sensitive prefabricated sensor for any pathogen.