Platypus Technologies is developing protein-detection assays based upon liquid-crystal technology to rapidly detect and report the presence of target molecules bound to specially designed surfaces.
As Richard Schifreen, Ph.D., president and CEO, explained, liquid-crystal molecules are rod-shaped and tend to align parallel with each other. That alignment changes, however, when target molecules bind to receptors that are immobilized on the surface of liquid crystal-coated substrate. The standard analogy compares the alignment to upright bowling pins, and the binding to the scattered pins after the bowling ball—the target molecule—has struck.
The dramatic difference makes direct detection of viruses captured by surface-bound antibodies possible with low- or no-power readouts based upon interrogation with polarized light. For a simple “yes/no” readout, a light image indicates presence of the target molecule and a dark image indicates absence of the target.
“The work is at the precommercialization phase,” Dr. Schifreen said. “The sensor can be packaged into an instrument, a badge, a handheld device, or incorporated into an alarm system.”
Platypus is currently developing a protein-detection assay for influenza exposure and water-borne pathogens, and gas sensors to detect nitric oxide and pesticides and to monitor asthma. “The advantages,” he said, “are low- or no-energy requirements, the inherent flexibility of a single format for multiple analytes, and the simplicity of a solid-state system. It’s very inexpensive, costing a couple of dollars at research scale,” versus about $100 for an electrochemical sensor.
“Detection speed depends on the particular system,” Dr. Schifreen said, but ranges from a few seconds to one or two minutes. “The assay can be either qualitative or quantitative. We’re working to optimize the system so it’s more specific, more reproducible, and, in some applications, reversible.”