Assessing the triad of biocompatibility, medical device functionality and biological safety

Implantable medical devices, including sensors and contrast agents, have crucial roles in diagnostic and therapeutic procedures that are intended to improve quality of life. They are usually very successful, but all too often they fail to deliver optimal satisfaction. Device performance, which is at the heart of patient safety, is dependent on the biocompatibility of the materials used, the functionality of the devices and overall biological safety of the system. The interdependence of this triad of critical properties is rarely considered within the testing and regulatory regimes that control access of the products to clinical applications. This paper analyses the details of a series of product types (intra-ocular lenses, metal-on-metal hips, coronary artery stents, nanoparticle contrast agents and closed-loop sensor-drug delivery systems) and identifies the difficulties when the connectivity between these characteristics is overlooked. The paper then addresses the generic weaknesses in preclinical testing programs and identifies a series of changes that could assist in resolving these problems, providing better assurance of patient safety.