Optical biosensor detects dry-eye disease using a patient's tears

The device allows rapid, affordable detection of very small concentrations of a patient's tears in vitro.

Recognizing the increasing demand of diagnosis for dry-eye disease, the Optics, Photonics and Biophotonics group at the Technical University of Madrid (Spain) has developed a point-of-care optical biosensor that allows rapid, affordable detection of very small concentrations of biological material—in this case, a patient's tears—in vitro.

Related: BioLight reports positive clinical study findings for point-of-care dry eye syndrome test

Dry-eye disease symptoms include eye irritation, redness, and fatigue, which can lead to retinal detachment and loss of vision in the most serious stages. These symptoms can be confused with other eye afflictions that are unrelated to the disease. However, dry-eye disease also affects tear composition by varying its concentration of proteins—the elements needed for proper diagnosis.

The point-of-care optical biosensor, licensed to BIOD S.L. (www.biod.es), detects lower concentrations (in the range of nanograms per milliliter) in a patient's tears in the same way professional labs do to detect these types of diseases. What's more, it is label-free, so it does not require labeling agents such as enzymes, fluorophores, or gold particles to amplify the response, making it low-cost as well.

The device's readout method is based on the change of optical properties of the sensors when biological material is added. Therefore, by monitoring the spectral response of the reflected light, users can determine the amount of biological molecules in the biosensor's surface, which can host tear samples as small as 1 µl without being evaporated.

Now, the research team is working on two other biomarkers for dry-eye disease, with the goal of developing a dry-eye disease diagnosis kit.

Full details of the work appear in the journal Sensors.

More in Biophotonics Techniques