Phononic cystal sensor for medical applications

We report on first steps towards a phononic crystal sensor for biomedical applications. Phononic crystal sensors are a new concept following the route of photonic crystal sensors. Basically, the material of interest constitutes one component of the phononic crystal. Here a liquid analyte is confined in a disposable element which acts as defect in a phononic crystal. In an application as biomedical sensor the concentration of a compound in liquid must be related to speed of sound of the liquid in the cavity. A change in the concentration e.g. caused by the appearance of a toxic compound or as a result of a biochemical reaction, results in measurable changes in the transmission coefficient, specifically a shift of a resonance induced transmission peak. Three additional key design challenges for a medical sensor are the strong restriction coming from limitations to approved materials for the analyte container, geometric dimensions in the mm-or sub-mm-range common in hospital or point-of-care environment and acoustic coupling between sensor platform and the analyte container.