While we’re still waiting for holographic TVs, scientists at University of Cambridge have developed holographic sensors that may replace many modalities that are currently being used to screen for disease and measure levels of various compounds in body fluids. The technology relies on using hydrogels seeded with silver particles that react to light. When a laser is directed at the hydrogel, the silver particles jump into predetermined shapes. The resulting hologram from light passing through the silver has a signature color. If a compound is present, the hydrogel inflates or deflates, changing the color of the hologram. Precisely measuring the color of the resulting hologram identifies the compound present around the hydrogel.
The individual hydrogel sensors cost pennies to produce and can be reused to perform the same test repeatedly. Right now researchers are expecting this technology to find its way into glucose testing, potentially replacing costly test strips, but there’s great potential for this technology to find use for other diagnostics.
From the study abstract in Advanced Optical Materials:
This tunable holographic sensor offers interrogation and a reporting transducer as well as an analyte-responsive hydrogel, rendering it label-free and reusable. A single 6 ns laser pulse is used to fabricate holographic sensors consisting of silver nanoparticles arranged periodically within a polymer film. The tunability of the sensor is demonstrated through pH sensing of artificial urine and validated through computational modeling.
Article in Advanced Optical Materials: Light-Directed Writing of Chemically Tunable Narrow-Band Holographic Sensors
University of Cambridge: Holographic diagnostics