Real-Time Monitoring of Urinary Encrustation Using a Quartz Crystal Microbalance

Encrustation on the surface of urological devices such as ureteral stents leads to their blockage. However, limited tools are available for fast and real-time monitoring and modeling of the encrustation process. In this work, we have developed a model for in vitro study of encrustation and coupled it to an online monitoring QCM technique. The QCM biosensor is precoated with a polymer that is representative of the surface of a ureteral stent and subsequently coated with urease to facilitate crystallization of calcium and magnesium phosphate. The changes in deposition of crystals on the polymer surface are monitored quantitatively using a quartz crystal microbalance (QCM) biosensor. The QCM sensor is capable of dynamic, label-free detection and has a very high sensitivity. Experimental data generated using this model shows that pretreatment of the sensor surface with urease significantly induces early stage encrustation as compared to the untreated sensor surface, which emulates the real encrustation process. This encrustation study model has a high utility in screening studies for materials used in urological devices.