New Coating Technology Extends Lifespan of Implantable Biosensors

Wearable and implantable biosensors that can accurately detect biological molecules in a non- or minimally invasive manner have vast potential for monitoring patients’ physiology and response to therapies. For example, wearable glucose monitors that measure blood glucose levels and convert these measurements into readily readable and continuously recorded electrical signals have become indispensable in the management of diabetes patients. Similar biosensors have been developed for the monitoring of electrolytes in sweat, biomarkers in interstitial fluid near the skin surface, and to report on the function of internal tissues.

However, these implantable biosensor devices are only useful for a limited time because of a phenomenon known as “biofouling,” in which either bacteria, human cells, or diverse molecules contained in the body’s biofluids build up on the sensor surface, blocking its interaction with the target molecule (analyte) it is supposed to bind, thereby interfering with its electrical signal-generating mechanism. In addition, implanted biosensors can provoke so-called “foreign body responses” through the unwanted stimulation of nearby pro-inflammatory immune cells that can cause fibrotic tissue reactions.